Engine - Cooling

Topics covered:

• Diagnostics for running hot
• Coolant (incl. Water Wetter)
• Radiators
• Fans (incl. clutches, electric fans, & thermal controls)
• Thermostats
• Water pumps
• Belts and tensioners
• Head Gaskets

Diagnostics for running hot

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From: Doug Aitken[SMTP:jdaitken@earthlink.net]
Sent: Saturday, July 15, 2000 9:54 AM
Subject: [D90] Overheating

Sorry for so many posts, but I forgot to post this site, which gives a nice list of EVERYTHING which can cause overheating!

http://www.osbornauto.com/questions/overheat.htm

Doug (finally a short post!)

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From: Doug Aitken[SMTP:jdaitken@earthlink.net]
Sent: Saturday, April 08, 2000 11:55 AM
Subject: Re: [D90] running hot

>I've noticed that my engine has started running hot ... and was wondering
>what I should do about it (besides drive around w/ the heat on -- not going
>to be fun in the summer). I plan on hosing off the radiator w/ a high
>pressure hose, to ensure I've removed all the mud and goop from the hoses.
>I was thinking of testing the thermostat ... what temperature is it
>supposed to open at? Also, I've heard some people talk of Water Wetter ...
>how good is it, how expensive is it, and how readily available? What else
>should I do?

Been there! I went through this problem last year! However, it can be a number of things!

1) Are you losing coolant? If so, it could be mild (leaking hose or heater core) - but this would not cause overheating. But, more pertinant, the V-8 is prone to popping head gaskets (and associated warping of the head....
This causes loss of coolant and overheating......
So first up, do a pressure test on the system to look for leaks. If no visible loss, seal off the heater loop and test again, to see if loss is in heater core. Connection between the cylinders and water passages will cause pressurization/frothing of the coolant......
If you have to have the head gasket changed, make sure they check the head is not distorted. Best case, it can be machined. Normally you need a new head.....

2) The stock radiator is prone to clogging. A pressure flush may help. A recoring job (a few hundred $$) is the (semi) definitive job. The ultimate is a rebuild (as Q did: I think he has it documented on his web site) 3) Have the thermostat and water pump checked....... (sorry, don't have the specs in front of me: someone with a workshop manual please chime in!)

4) Are you running the stock fan with viscous coupling? If the coupling is shot, you will not have decent cooling. Testing the fan is a black art: There should be noticable resistance, but the techniques for testing this are varied and pretty subjective...... If you have to replace: shop around as prices for the couplings can get pretty wild! I know Motorcars in Houston have reasonable prices - (800) 338-5238 - ask for Ken Karr and try and squeeze an extra discount out of him!

5) When the system is 100%, add water wetter (made by Red Line, available in Pep Boys and some other major parts dealers (and any speed shop!): it works! But no point in adding it until you have a good system!

Good luck
Doug
Doug and Kim Aitken
'95 Red Defender 90 5-speed

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From: Craig Reece[SMTP:craigreece@earthlink.net]
Sent: Saturday, July 15, 2000 11:59 AM
Subject: Re: [D90]Radiator crud?(long)

Doug (and Cliff,)
The conclusions I draw from the discussion of Rover overheating so far are (and I've added some stuff: )starting from least expensive and moving up the ouch! scale:

1. Maintain a 50/50 mix of coolant/water (or slightly more water in the summer, since water is a better heat conductor) to guarantee that your cooling system has the proper amount of anti-corrosion additives.

2. Use distilled water instead of tap water.

3. Change (but don't backflush) the coolant frequently.

4. Check the thermostat and viscous fan coupling frequently, (and perhaps change at least the thermostat preventatively at some regular interval?) Carry spares for both as well as belts and hoses, obviously. Expeditions - carry water and coolant. Make sure timing isn't retarded and that your fan shroud is ok. Make sure you don't have head gasket leaks or head cracks that are adding exhaust gasses to the coolant.

5. Consider aftermarket anticorrosion additives such as Eastwood's No-Rosion. Consider using RedLine Water Wetter or similar products such as 40 Below.

6. Consider propylene glycol antifreeze both for it's non toxicity as well as it's reported better heat transfer.

7. Consider changing to straight Evans coolant.

8. If you suspect a plugged radiator - the internal tubes plugged with corrosion - have the radiator removed, hot tanked and rodded. (For mud in the cooling fins, a good bath at the car wash will do.)

9. Consider adding louvres to the hood, or holes on the side as some have done - to allow heat buildup in the engine compartment to escape.

10. Consider a custom made radiator with larger tubes as Q has done (and I think it's described under Custom Mods on the D-90 site.)

11. Consider a custom made radiator, including tanks, made of aluminum. Griffin is one company that will do this.

12. If you have an automatic trans, consider adding an aftermarket cooling radiator, perhaps with its own fan and shroud, and consider mounting it somewhere other than in front of or behind the (stock) radiator.

(And there may be other things we've forgotten - this list is just an attempt to start the discussion.)

Craig Reece

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From: Doug Marbourg[SMTP:marbourg@lanl.gov]
Sent: Wednesday, August 16, 2000 9:28 AM
Subject: RE: [D90] Overheating again

Hey Barnett,
This thread has been floating around now for some time. Seems all of us with significant miles on our rig's are/will experience this at one time or another.

For years I NEVER had any type of cooling issue (94 D90). That was until about 4 months ago. I was SURE it was a clogged radiator...Got it rodded...Fixed?...Nope. Then I thought that I didn't burp the air out of the system properly...Nope. Then I added some supper cool (aka Water Wetter)...Nope. Fan Clutch?...Nope. Gauge?...Nope. T-stat?...Nope.

Hmmmmm. Head gasket?...Yup. But before I decided to tear down the top end of the vehicle I wanted a definitive diagnosis...Pressure test?...Nope. Pull the number 1,2,7 & 8 plugs to see if they were clean (symptom of coolant egress)...Nope. Sniff for hydrocarbons?...Nope. Hmmmmmm. What to do?

I tore down the top-end anyway and low and behold it was the shim gasket. You could see were there was some carbon build-up between the water jacket and the #1 cylinder. Funny thing was I wasn't loosing coolant. Turns out that what can happen is the coolant can become aerated via the leaky gasket...Once it's aerated enough the system can't desapate the heat...Tricky eh? I'm still surprised I the sniffer test didn't pick it up though.

I'm glad I did the tear-down. I'm intimately and infinitely more knowledgeable about the workings of our engines now AND she runs smother and better than when I bought the truck. No more stalling problems either!

Good luck!
-D

Coolant (incl. Water Wetter)

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From: Robert Dassler[SMTP:roadsiderob@hotmail.com]
Sent: Sunday, July 16, 2000 10:29 PM
Subject: [D90] coolant crud

Hi everyone

Just a couple of thoughts on cooling systems. When replacing coolant in your Rover, it is important to use coolant that is made to be compatible with Aluminium. A lot of the coolants on the market (especially the stuff you buy at the auto parts store) use silicates which (I think) help to lubricate the waterpump, etc. This is fine for a cast iron engine but too abrasive for aluminum. Finding a coolant that is specifically designed for aluminum (non-silicate) will help. Many auto manufacturers sell their own coolant for this reason. When we do any repairs in the shop, we always use Rover coolant--it is required by Rover. In the past, I have also used coolant from Honda and I think Mercedes Benz has a very good aluminum compatible coolant as well. To date I have 100,000 miles on the D-90 with no cooling system problems at all--the radiator has never been out at all. My Range Rover recently began running hot on extended drives or when running the A/C around town. I sent the rad. out and was told that the core was rotten. When you pull the fill plug there was a lot of crud plugging the tubes. After installing a new factory radiator, the temp gauge always reads below half. If you have a partly plugged core, you will have hot and cold spots on the radiator. Also, as a rule of thumb, the upper hose will be about 25degrees hotter than the lower hose. If you have inlet and outlet temps that are the same, the radiator is not shedding the heat.

Rob Dassler

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From: Perrone T. Ford[SMTP:ford_p@nettally.com]
Sent: Thursday, October 12, 2000 12:17 PM
Subject: Re: Anti-freeze

Have a look at this:
http://popularmechanics.com/popmech/auto3/9903AUSMM.html

I think you may find it VERY informative!
The new stuff is really for cars with aluminum radiators. It will hurt vehicles with copper/brass radiators.

-P

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Date: Fri, 30 Oct 1998 08:50:08 -0600
From: "John C. Hinkle" defender110@email.msn.com
Subject: Re: [D90] Running Hot

>>I'm also running water wetter. You just can't get too much of a good
>>thing. (Cooling) Plus I can just flip the fans off in the winter to
>>help it stay warm.
>What is water wetter and that redline stuff people keep mentioning? I have
>not seen it before.

Brian-
The stuff is Red Line WaterWetter Supercoolant it's about $7.95 from Summit Racing. It is a cooling system heat transfer agent for water or water/antifreeze.

Chris Hinkle

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From: Daniel S. Hayes[SMTP:dsh12@ix.netcom.com]
Sent: Thursday, February 24, 2000 11:55 PM
Subject: [D90] RE: cooling

When filling the system after it has been drained, it is required to disconnect the hose from the engine to the heater [at the heater core] while the engine is running to remove the air lock/bubble.

I was having the same overheating problems after draining the system.

Dan

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From: Doug Marbourg[SMTP:marbourg@lanl.gov]
Sent: Wednesday, August 16, 2000 9:44 AM
Subject: RE: [D90] Overheating again

>How does one "burp the air out of the system properly"?
It's a bit of trick, but not really hard. What I do is I pull the plug at the radiator. I then fill the system while gently squeezing the upper radiator hose. You will see (sometimes) the bubbles burping when doing this...Even when you think it's full full. I use a small funnel an wedge it in the filler hole such that it doesn't leak much. Each time I would think the rad. was full only to see it suck down more coolant in the funnel. I then replace the plug and fill (to the top) the expansion tank. Then drive around for a few miles till hot, and check the level of the expansion tank again. I've had the system completely drain the full expansion tank, and other times it didn't drop an inch (in which case I would remove some of the coolant to 1/2 full). I really don't think cavitation is a big issue, unless you have a HUGE air pocket in the system.

Hope this helps.
-D

Doug Aitken[SMTP:jdaitken@earthlink.net] added:
Just a little addition to this: Put your vehicle on a slope: front up. This helps the darn bubbles caught at the back of the block to migrate out. Evidently (according to our local LR Master Mechanic) there is poor water flow to the back end of the engine and this is generally where bubbles get caught, causing a local hot spot, which can develop into a gasket failure......

Don't forget the heater loop also!
Good luck!

and Alan E. Foster[SMTP:alan.foster@vt.edu] added:
Although this seems intuitive, it is contrary to the steps outlined in the manual, which say you should open the system, fill from the heater loop, and run the engine until all air is removed (oversimplified, since you can just read it for yourself); I originally tried the method outlined below when I changed my water pump, and it does work, but was taking forever -- after consulting the owner's manual, the instructions there had all the air out in no time.

-Alan

Radiators

------------------------------

From: Kelly Minnick [mailto:kminnick@gte.net]
Sent: Tuesday, March 20, 2001 11:47 PM
Subject: RE: 3.9L rad plug

Looking at the parts manual now... NTC4609 is indeed the plug (I grabbed the wrong part #ERC319, which is the whole heater tube...). The O-ring is NTC5171 (for reference). My '89 RR also has 2 of these. The metal one on the radiator and the plastic one on the heater pipe fill location. Funny, but the part manual uses the same # for both locations... Thanks to both of you!

Kelly Minnick

Kevin Kelly [mailto:kkelly6788@earthlink.net] added:
I just pulled my spares out of my parts bag and the plugs I have (purchased at LR Marin last year) have an O-ring that fits in to a groove in the plug (no gasket required). The part number on the bag (with a LR sticker) reads "ERR 4686 Plug, Radiator"

The metal plugs are NLA and I was looking for one a couple years ago after some people were having problems with the plastic plugs stripping out. Famous Four in GB had some used ones but asked me "If I would want a metal plug and risk stripping the threads on a $500+ radiator or use the plastic plug and risk stripping the threads on a $2 plug". They said Land Rover made the switch to plastic plugs to avoid stripping the radiator threads.

Kevin Kelly

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Date: (unknown)
From: "Chuque Henry" [SMTP: q@d-90.com]
Subject: Custom radiator with Electric Fans

I made mine (radiator) the thickness of the radiator brace and tanks. You can't fit a radiator this thick with the stock fan. With elec's it actually works better for mounting because everything is flush. The new radiator is bigger, but I had them space the fans out so that it wouldn't get clogged as easily. It has a slightly better efficiency rating than stock. Almost all radiators are a serpentine fin design (like the stock one) but I used flat fins so that I could have the fins solder dipped for strength. This allows the radiator to be cleaned out with a high-pressure hose.

I use two cheap fans that are ignition switched with a power cut off for deep water. It would be nice if they had a thermal switch, but I haven't gotten around to it. I just leave them on all the time in the summer, off all the time in the winter. Oh well. I run a 14" and a 10". I think the set cost me less than $100 at the local parts store. I can replace them individually and cheaply anywhere buy taking out 2 screws and they have never failed. They have been subjected to deep water and mud as often as possible.

I'm not sure how much it cost I'm sorry to say. As I remember, they accidentally quoted me the price for the 'moderate' upgrade radiator and then ordered the big dog. I think mine was near $300 but should have been near $500. They had quoted me like $200, but I agreed to at least pay the cost of building, so they wouldn't get screwed, but they didn't make any profit. Good people.

I talked with Jack at Lincoln Radiator a little more and found out the following information. Our (and most) radiators are serpentine fin design, and I have a flat fin design. Only flat fins can be solder dipped. The company who built the core makes only cores. There used to be several companies that made cores, but three companies (GNO, Daniel and Magun) consolidated and became Gordan Industries or GDI. They have plants all over the country, but most specialize in a special type of core. I was going to get mine from Kansas City, but they don't do solder dipped cores. They plant that did is in Dallas, TX.

Jack said any radiator shop worth it's salt will know what to do if you ask for a flat fin, solder dipped, custom core radiator. He also said you could call him with any questions you have on his 800 number. (800) 204-6221

He would be happy to build a set of radiators, and would even get a discount, but he said you would be better to have it done locally. you can find your local radiator shop at:
http://www.radiatorinfo.com/

Here are the specifics on my radiator. I'm sure you could get the work done locally.

I called around and found a place that does custom core radiators. They don't actually build the core, they just take the measurements and make the calculations and then order a new core from Texas. The stock radiator is a great car design, very efficient and they commented that the tanks and core were first class. But it is also a 'mud catcher design for off-road use. The fins are so close that crud just wants to get packed into the radiator all the time. It's also hard to the clean because the super thin fins will bend if even the slightest pressure is applied making it near impossible to work the debris loose.

I was aiming for close (but slightly better) to the same efficiency as the stock radiator in prime condition while opening the radiator up as much as possible to avoid mud gathering. Because I am running electric fans instead of the stock clutch fan, it freed up some space. If you look at the stock radiator, you'll notice the core is not as wide as the frame. I had the new core built to the full width of the frame making the radiator much thicker. They calculated the fewest number of fins they could use to have close to the same efficiency as stock. This was the design we went with.

To make the fins stand up to pressure washing, we went ahead and had both the front and the back of the core solder dipped. This makes the fins MUCH stronger. I probably could have gotten by with just the front, but I was going for 'the full Monty' as it were.

Another option I chose was to go with a straight fin design. Most radiators I've ever seen use the zigzag design where the fins to back and forth between each row like this...

____________________
VVVVVVVVVVVVVVV
____________________
VVVVVVVVVVVVVVV

The advantage of straight fins are that the fins run the whole length of the radiator making it one solid piece.

_______________
|_|_|_|_|_|_|_|_|_|_|
|_|_|_|_|_|_|_|_|_|_|

I've been watching, and I haven't seen this design in many places. I've noticed that home A/C units tend to use this design for strength. This is also is probably not necessary, but I didn't want to by another radiator again for a long time, and I was just feeling like getting every possible option at the time.

The use your old tanks and frame. The only thing they replace is the core. So it looks stack and of course fits great. I took mine out and dropped it off. Picked it up, put it back in, used distilled water and antifreeze and a bottle of Redline Water Wetter. The only time it's gotten hot since is when I forget to turn the fans back on.

The end result is that I have a bulletproof radiator. It cools great, it cleans up nice and you could stand throwing rocks at it all day and never hurt it. They said that they had only built one other like it and that was for a sprint car. The guy would typically go through several radiators a season. He brought it back after using it entire season to have it flow checked. It was still like new, and they haven't seen him since. I like it.

Call around and ask the radiator shops. It wasn't that expensive and the first place I called did it. You can probably keep the cost down and get the efficiency way up if you just have them build a radiator that was like stock only thicker. I just wanted it to work like new and stay that way.
Chuque Henry - 1995 Defender 90

_______________

The radiator is 16.5" x 29.5" x 3". It has 40 rows of 3 cores which gives a core size of 15.25" x 25" x 1.75". The radiator frame is actually built for 4 cores with the rear (near fan) cores not in place. The radiator is held in place by two 1" pegs top and bottom that are 19" apart. The opening at the rear of the shell that a fan shroud must cover is 15" x 24.5". So the shroud should be a bit larger in each dimension. The Flex-O-Light 210 many have used is the perfect width but a bit short in height. I simply added a 1.5" wide x 1/8 thick aluminum piece at the top of the radiator shell to make the opening smaller and allow the fan shroud to seal all around.
Rob

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From: Shannon Holland [mailto:holland@loser.net]
Sent: Tuesday, July 30, 2002 10:43 PM
Subject: Re: Mysterious 110 radiator disease

OK, I think I found the pdf I was looking for (plus one other). These both talk about different methods of relay suppression and the possible adverse effects on the relay (suppression basically causes the relay coil to take longer to de-energize leaving a possibility of the relay contact being partially disconnected which can cause arcing and possibly
weld the contacts together - ouch!).

At any rate, the method they recommend is regular diode in series with a zener diode - this limits the negative voltage spike without increasing the relay disconnect time too much (an example they list is 1.9ms versus 1.5ms).

http://relays.tycoelectronics.com/app_pdfs/13c3264.pdf
http://relays.tycoelectronics.com/app_pdfs/13c3311.pdf

Oh, and no pdf (but some plugin that I don't have):
http://www.leachintl2.com/english/english2/vol6/properties/how7.htm

For all sorts of listings:
http://www.google.com/search?hl=en&ie=ISO-8859-1&q=relay+diode+suppression

Shannon

On Tuesday, July 30, 2002, at 10:16 AM, Shannon Holland wrote:

> I'll ask Philippe for the part. I also found a really another good
> description of how to deal with the spikes (I think the link I posted
> before was a more a description of why they happen). It was pdf which I
> printed, I'll try to dig up the original link. Turns out you can use
> either a diode or a resistor.

Fans (incl. electric fans & thermal controls)

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From: "Gomes, David" david.gomes@gambrobct.com
Sent: Thursday, May 30, 2002 7:05 AM
Subject: Fan Clutch Diagnosis

> "...What's a real reliable way to check the fan clutch?..."

That's a great question, Bob. Unfortunately, I've never seen a really good answer. About the best I could do is, with the truck cold and engine off move the fan counterclockwise (as viewed from the radiator) by hand and get a feel for the resistance that's there. Then get the truck up to operating temperature, shut off the engine, and go move the fan by hand again. You should feel more resistance than you felt with the engine cold.

I'm not sure about a specification for the resistance force under either condition, but if it's still loose when it's hot, you can bet it's not doing it's job. This is probably one of those things we should all do when the truck is running properly, to get a feel for the "baseline condition", so to speak. So that when there's a problem, you can repeat the test and know if it's the same or different from when it was working properly.

One other "gotcha" I've seen is a lot of gunk built up between the radiator and the AC condenser. Everything looks good from front and rear, but crud in between is blocking air flow.

-Dave G.

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From: Q[SMTP:q@d-90.com]
Sent: Wednesday, August 16, 2000 8:07 AM
Subject: Re: [D90] Re: Electric Fans

Robert D. Leggiero just sent me an EXTENSIVE report on how he installed his electric fans. It is very well thought out and makes me feel guilty for the way I did mine. Check it out at:


Even so, doesn't this nut just hold the pulley assembly to the water pump shaft? What holds the fan clutch to the end of the shaft? Nope: Its all one big chunk and leaves you lots of room!

Doug

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Date: Wed, 06 Sep 2000 19:20:20 -0700
From: Jeremy Bartlett bartlett@slip.net
Subject: Re: Which Automotive Tools?

> If I am correct a 36mm wrench fits the fan clutch.

On '97s you take the fan off with a narrow 36mm. On '94 '95 it's 1 1/4

Jeremy

------------------

Date: Mon, 18 Jan 1999 18:53:21 -0600
From: daitken@sugar-land.anadrill.slb.com (Douglas Aitken)
Subject: Re(2): [D90] Electric fan source

Check out the full specs of the Flex-a-lite at:
http://www.flex-a-lite.com/auto/lowprof.htm

There is a link to a nice How-To from Four Wheeler mag also. Should help a few of you make up your minds. Now you just gotta shop around for the best price!

Doug

------------------------------
Date: Wed, 21 Apr 1999 18:10:35 -0500
From: Bill Ritchie billnsandi@kingwoodcable.com
Subject: Re: [D90] Electric fans

I did the electric fan install about 2 months before the twistoff. Used a FlexiLite 210 Puller with adjust. thermostat. ($180 from Summit Racing - free shipping and came in one day)
The install is pretty easy and looks slick as heck - took about 2 hours. You can remove your existing fan cowl and fan (need a real thin wrench to get the fan off) in no time. Use the existing mounts for the cowl by bending the 90 degree angles to 180 degrees on the top and the bottom. The fan will fit between them perfectly - drill holes in all four mounts through the metal into the fan frame, then use some sheet metal screws or the like to fasten them. There will be a small area of the top portion of the radiator that is not covered by the fans which can be filled in with your choice of materials. The soleniod and thermostat pack can be installed on the horn mounting plate very easily. I taped into an unused circuit on the underhood fusebox (must be at least 30 amp fused). I also installed a manual cutoff switch for the fans in the cab (for fording). Power for the manual switch is keyed so the fans turn off when the ignition is off. I soldered all the connections and siliconed the connections on the thermo-relay box.
Performance before the TO was great. I never noticed a difference in temp guage compared to the old mechanical fan (which was replaced by electrics because I broke off two blades will in deeeeep mud). And is was nice to be able to shut off the fan. When the fans engage there is a slight decrease in idle speed (I guess the added drain on the alternator). You can hear the fans when engaged and traveling less than about 10 mph (they are fairly loud). I didn't notice any power gain when the fan is off.
Now for the downside:
During the trail ride from GJ to Moab I noticed a sharp increase in the temp guage and stopped to check things out. The inline fuse holder supplying power to both fans had melted (the fuse was not blown). After a quick replacement with parts from none other than the God of Spare D90 Parts and Trail Fixes - Alan Dobbs, we were on our way. Only to fail again a short time later - this time a blown 30 amp fuse. At this point we did more diagnostics and figured out that one of the electric motors was "dead" and would blow fuses and barely turn (sounded like grinding metal). So we isolated the one working fan, supplied it with power (very easy to do with the supplied wiring harness) and were on our way. There was a noticible increase in the baseline engine temp, but it stayed in the safe range.

I haven't pulled the bad fan yet, but Summit sent me a new 210 (charged my credit card for it until I send them the old one) which I am installing this weekend. Alan Dobbs and I will check out the bad electric motor and report the diagnosis. (I have a sneaking suspicion that several deeeeep fords across salt water down in Galveston may have corroded something).

More later,
Let me know if anyone is interested in some install picts and such.

Ooops, forgot to add some stuff,
If I had it to do over again, which I do ;). I would wire the fans with individually fused power leads so that if one failed the other would keep working. I would also have a warning light near the manual switch wired such that when the fan is actually turning it is lighted (at times I didn't know if the fans were working or not).

Bill Ritchie
'97 AA Yellow D90 #2078 (DRS, 35's, Detroit, TT, 4.1's)

_______________

_______________
FINALY! I found the thermostat switch I've been looking for my FL-210 fans. It's the exact same dimensions as the AC cut-off switch that screws into the thermostat housing. I had taken the AC switch to an auto parts store before and found a fan switch off a Porsche that looked right only to find when I got home that the threads were slightly off. This time, I took the thermostat housing with me as well as the AC switch and hit a different store. The guy there was really into what I was doing and helped try a bunch of fan switches until we found one from a Volkswagen that was perfect. $15 complete with gasket. I like it a lot better than the bourdon tube deal that comes with the fans. It's marked in Celsius as 92/87C which is 198/189F. The thermostat is 88C or 190.4F so it should work perfectly and is a much cleaner installation. If it works out. This is a mod anyone can make to their 90 even if they have AC since you really don't need the AC switch. It's just a switch that is normally closed and will open to prevent the AC compressor from running if your engine is overheating. I cleaned off the AC switch so I could see the numbers on the side. It looks like it's set to open at 109C or 228F. So, your rig would have to really be cooking before it kept your AC form running. Oh yeah, the fan switch is Beck/Arnley Worldparts Corp. part no 201-0809

Chuque Henry added: FYI Pep Boys helped me look up the part (Beck/Arnley 201-0809) and found it's the fan switch for the following Volkswagen's:
75-84 Rabbit
80-83 Jetta
74-80 Dasher

and now, back to garage,
Rob :-)

Thermostats

----------------------

Date: Tue, 13 Apr 1999 07:54:57 EDT
From: SPYDERS@aol.com
Subject: Re: Re: [D90] 3.9 V8 Thermostat

n a message dated 4/13/99 12:48:38 AM, you wrote:
>There is nothing special about the thermostat in the 3.9. NAPA will
>probably list one for the RR.
>
>Larry (BTDT)>

That's what I thought too.
The thermostat in my engine has a little hole at the 12 O'Clock position, and the one in my friend's engine (sourced from a non-genuine source) doesn't... it may seem trivial, but then I saw this in my book:
>From my shop manual, Section 26 / Cooling System / Page 3:

To Refit:
6. The thermostat has a small vent hole in which is fitted a 'jiggle pin' to keep the hole clear. Fit the thermostat to the housing ensuring that this vent is uppermost at 12 o'clock position. If fitted in any other way, an airlock could result in the watter passages causing overheating and coolant loss from the system.

So anyway, I sent him a copy of that page and he drilled a hole to see if it would help. At the same time, he used Prestone Radiator Flush and ran it through his engine for a few minutes. He then drained it from the radiator and then re-flushed with water prior to re-filling with coolant. Now the cooling problem is worse! The needle goes to 3/4 just by driving around the neighborhood, at night, slowly with no appreciable load.

(I'm 3 towns away and running out of suggestions, and he's fretting that his truck will miss our Rally this weekend. I know that several people on the list from the North East were hurriedly preparing for the Twist Off and I can sympathize with the frustration that a deadline like that adds to what should be a simple troubleshooting.)

- --pat.

Water pumps

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From: Cliff[SMTP:gfai@mindspring.com]
Sent: Tuesday, August 01, 2000 8:56 PM
Subject: [D90] Update on Rimmer

....[extra stuff removed - ed.].....
"However", the electric waterpump seems to be a bust. If I recall him correctly the electric pump flows 85 litres (?) and the stock pump flows 125 litres (?). It was insufficient to cool the truck properly. It never overheated, but affected the performance of the engine and timing accordingly. The stock pump is back in place now.
....[extra stuff removed - ed.].....

Cliff

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From: Juan Goodyear[SMTP:jgoodyear@firsttech.com]
Sent: Thursday, July 27, 2000 4:02 PM Subject: [D90] Water Pump

I found it easiest when i removed a bolt from the old water pump to place it in the corresponding hole in the new water pump. There are about 12 bolts it seems if my memory serves me right that there are 3 different lengths of bolts. hope this helps. Oh yeah and the fan bolt comes off backwards ( a left handed thread I think is what its called?), anyway it I used the belt that drives the water pump to hold the pump from spinning when you are taking the bolt off. I seem to remember unbolting the fan from the clutch assembly before I loosened the big bolt. I can't remember why or if you need to but there are 4 bolts that hold the plastic fan on, they are really a pain to get at. you will have to remove the black pulley wheel for the power steering, it does not look like you would need to but one of the bolts is too long to come out if you don't pull the wheel off. I think there are just 3 bolts around it or something like that not a big deal but frustrating when you see the end in sight and you have t stop to take one more thing off. Feel free to call me if you need any help I did mine about 6 months ago or something like that.

Juan
red d90 94 #1039

Larry Michelon[SMTP:lmichelon@i-c.net] later added:

> 1. Will I need to remove the fan, or can I work around it? If I have to
> remove it, how in the heck do I remove the sucker (that's a big honking
> nut(!) ... is it reverse threaded?)

I have not replaced the water pump, but have had the fan out more times than I can remember. I believe the D90 is set up like my RR. The nut takes a 1-1/4" wrench (but it may be metric) and is reverse thread. If the belts start turning, stuff a rag in between the belt and the pulley, this should wedge in there and give you enough force to work against.

> 2. It seems if I can just get the belts outta the way, I should be able to
> swap the pumps (once I've drained the system) ... so ... what's the best
> way for getting the belts out of there?
There are tensioners on two of the belts (if you have A/C). The belt for the steering pump and alternator are pivot mounts, but you have to take the alt one off first.

Larry M.

At 05:31 PM 7/27/00 -0400, you wrote:
>Does anyone have any advice for replacing the water pump? This is the
>first sort of work I've done to that area, so I've got some questions ...
>
>1. Will I need to remove the fan, or can I work around it? If I have to
>remove it, how in the heck do I remove the sucker (that's a big honking
>nut(!) ... is it reverse threaded?)

Remove it! along with the shroud, of course! 1 1/4" reverse thread: you gotta knock the wrench clockwise.....

>2. It seems if I can just get the belts outta the way, I should be able to
>swap the pumps (once I've drained the system) ... so ... what's the best
>way for getting the belts out of there?
Do you have serpentine (97) or separate belts (94-95)? Whatever: they all have a means of tensioning: just release the tension and pop 'em off!

>3. What obvious things am I missing? Can I change this in under 4 hrs?

I would think so! Just be super careful when you assemble everything to fill with coolant correctly, including the heater loop..... be prepared to top off the level a couple of times to get all the trapped air out of the block.........

Doug A

Doug later added:

At 05:02 PM 7/27/00 -0500, you wrote:
>.........I seem to remember unbolting the fan from the clutch
>assembly before I loosened the big bolt. I can't remember why or if you
>need to but there are 4 bolts that hold the plastic fan on, they are really
>a pain to get at.

Nope: not necessary: you can get the whole thing off in one piece. but you will need to pop the four spring-loaded screws holding the shroud to the front bodywork and when you unscrew the fan, wiggle/pull both fan and shroud out at the same time.
Doug A

Well, the water pump is installed, and it went relatively uneventfully; lost one nut to the gods, gotta get a replacement from the HW store, but all else went well. The old pump had some nasty scoring due to bearing slop, but the new one seems to be working well.

FAQ info: I went down to Advance Auto Parts with the pump in hand, and spoke with one the guys I know down there pretty well. He found the pump in a catalog, and said they'd match any advertised price I could find, their list is for $179.63 P/N is 1312113. I figured someone out there might be able to use this info someday. Sure would beat getting your pump held up by customs (which I guess might have happened because the description on the box had, in many languages, the words "Water Pump" ... which in Spanish was written "Bomba Agua" ... guess they didn't take too kindly to the word "Bomb" ;-) )

-Alan

Without being able to hear the noise it will be difficilt to tell exactly but I can give you some information. The 1995 range Rover used a single serpentine belt which runs pretty quietly. Alternators are frequently noisey on these cars--usually bearing noise. We have seen water pump seals make noise--no leaks or pump problems but a moaning noise at low speeds--can sometimes be duplicated by turning the pump by hand. If the noise is a ticking or popping noise--check for loose or cracked pulleys. I could not find a specific test for the viscous unit but basically if it freewheels or is locked up it is bad. If it is leaking it is bad. If the noise is that of a locked up viscous (fan noise) when cold--this is not abnormal. The viscous is designed to freewheel until the temp causes the silicone fluid to thicken at which time the fan locks up and starts working. When this happens you can hear it kick in at speed. When the viscous is cold, the fan will be engaged until it warms up a little. When the viscous is turned by hand there should be some resistance. You could try comparing it to another car (same temp). How long does the fan stay engaged at first start? Usually when a viscous fails it locks up completely and the fan will stay engaged all the time. Write back with more info if possible

Rob Dassler

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From: Gomes, David [mailto:david.gomes@gambrobct.com]
Sent: Thursday, July 11, 2002 9:19 AM
Subject: RE: replacing 3.9 V8 water pump - any suggestions?

My 2 cents is, give it a good college try without pulling the radiator. I've never needed to. The more connections you open up, the better chance of something getting buggered or leaking. If the fan nut is stubborn, make sure you whack the wrench alternately in both the left and right directions to help shock it loose. And if you're going to do it this weekend, you should have already given things a spray of WD 40 (being careful to keep it off the belts and pulleys).

Not sure how many miles you have on the 110, but if you're removing the belts, it would be a good idea to remove the tensioner pulley, check the bearing condition, and soak it in oil while you do the rest of the water pump job. Clean the oil off the outside of it with brake cleaner and rags before reinstalling it. A catastrophic failure of that bearing is an ugly thing, and it's been known to happen.

You can do the water pump job with little or no fluid spilled on the ground if you pull the plug from the top of the radiator and use a small diameter tube (1/4-3/8) to reach down into the radiator, through the center of the tranny cooler coil, and siphon the coolant out into waiting jugs. When I've done it this way I never spill more than a cup or so of coolant when the pump comes off.

Use Permatex hylomar HPF [NAPA] on the gasket, and on the threads of the bolts when you install the new pump.

-Dave G.

If you have a '97 with serpentine belt you put a wrench (cant remember the size right now) on the bolt in the center of the tension pulley and lean down until enough tension is released to remove the belt. The shroud is a bitch to remove there is a double lip (picture a set of stairs) that feed through the slot. You kind of have to work the shroud up down and out (which is the point it hits the belts) It can be done without removing the belts if you bend it enough but before reinstalling I trimmed the edges off for easier access.

Chris "V"

I'm replacing my belt tensioner (the bearings are getting noisy - could blow soon) and was wondering if there were any tips for replacing it.

Just swap it out with the old one and adjust it so that the belt is just as tight as before?

You can replace just the bearing and save a lot of money. A new bearing is about 1/3 the price of an assembly. Your dealer can get them if they do not stock them. sorry, I do not have a part number handy. All you need is a bench vise and some sockets to do the job. If you cannot get one locally, write me back--we stock them where I work. I usually replace mine every 40,000 miles or so. It is a real mess if they fail.

Rob

Hey kids.

I made another call to my friends at Whistler Bearing (interesting choice of names, now that I reflect on it....) a minute ago to check on availability of the bearing Chuque needs for the ARB compressor. They had it in stock for $18 (no min order at Whistler).

By some miracle, I also remembered that I'd posted the number of the belt tensioner bearing on the 4.0 during my 60k service article, but had never gone looking for one. By the time the fellow came back on the line to tell me he had the bearing for the ARB, I had the number up for the tensioner bearing ( NTN 6203 LV ). When I mentioned this number, he recognized it right off as a very common bearing and came back right away saying he had them in stock. Price....$7.43 each.

I'll replace it every time I do the belt for a price like that!

If you don't have a local bearing supply (check your yellow pages), call Whistler in Denver at three-oh-three, three seven seven, fourteen sixty.

-Dave G.

Hi everyone,
Regarding head gasket replacement on a D-110. Originally this Rover came with three row heads and steel shim head gaskets. You can replace them with the same or update them with the composite gaskets. If you opt for the composite gaskets you will only use the upper two rows of bolts--the bottom row is no longer used. The composite gaskets also require replacing the original head bolts with the new type stretch bolts. These bolts are not torqued in the traditional manner. They are tightened to 20nm then turned 90 degrees, then turned another 90 degrees in sequence. I would recommend that you have the heads skimmed when you have them off if you are going with composite gaskets. It is not absolutely necessary but doing so will help maintain the proper compression ratio. If the engine overheated at some point you will want to check the heads and block for warpage. I have yet to see a block warped but the heads may be. skimming them will correct this. Specs are 0.002in max for steel shim gaskets, 0.006in max for composite gaskets. While you are at it, replace the exhaust manifold to head gaskets with the newest type stainless steel sandwich gaskets (4.0/4.6 style) which are far more reliable than the old style. Also, make sure that you get the latest rubber valve cover gaskets, valve cover bolts, intake gasket, updated end seals, and updated(wider) end clamps. I would say that $1500.00 is about right if you have a shop do the work. You are looking at 10-12 hours of labor, roughly $350.00 in parts for a composite gasket update, plus machining costs.

Hope this helps.
Rob Dassler