overheating- what should i check?

[MiniGuy]

My 1994 D-90 has developed an overheating problem. I pulled the thermostat and boiled it and found that it was opening and closing, although I am not sure if it was opening as far as it should. As an experiment, I re-installed the thermostat housing without the thermostat with the idea that would guarantee constant flow of coolant to the engine and would let me know that the problem is thermostat related.

Well, even without a thermostat to block coolant flow, the D-90 overheats just the same.

Where do I look next. My water pump was replaced about 20k miles ago. Perhaps it is going bad? Is there a way that I diagnose if the problem is the water pump? Or could it be something else I have not considered.

I have limited funds to repair this, so if I have to take it to a dealer/mechanic I want to be able to be as knowledgable as possible so that I do not pay more than necessary to get my D-90 running again.

Thanks for any help anyone can offer?

Also, anyone know of a good independent Land Rover mechanic in the Birmingham Alabama area?

Thanks!

[chrisvonc]

Another common problem is the radiators. You may want to have that checked as well as make sure there are no air pockets in the system.

[MiniGuy]

The radiator is certainly full, does that mean no air pockets in system?

How would I check to see that the radiator is flowing properly?

[scot]

Even if your radiator is full..you have a ten year old truck. Land Rover isn't famous for it's radiators. My truck overheats too. I (and probably you) just need a new one...they fill with sediment, and if you go mudding, the constant muck beats the fins silly or fills the gaps with mud. Take a flashlight and look real hard inside the engine compartment and examine the fins...that'll probably show you why you overheat. BTW..and Land Rover radiator is more than 500 bucks...but at www.radiator.com they claim they have one that fits for $350. Hope that helps.

[Gkase]

I just went through this...turns out that the fins around the center of the radiator were corroded to non existance, the fan clutch was shot AND it had head gasket leaks...indeed, 94 trucks had crummy head gaskets, the new ones work better longer (I hope)...I bought a recored radiator off of D-90 here for $150 and dumped the fan clutch and fan and installed the electric fan option detailed elswhere on this site...new head gaskets and overheating is over...good luck!
George

[MiniGuy]

Crummy head gaskets? You mean all that black oily stuff on either side of the engine? ;) ;) ;)

Yes, I have that too, but not my main concern at this point. Sounds like I am overdue for a new radiator and will pursue this next week.

I do know my water pump should be pretty good as it was the last major part replaced about 20k ago.

Thanks for everyone's help and suggestions. This is now a bigger job that I am willing to do myself so I will turn it over to the pros.

Last question: Does anyone know of a good independent LR mechanic in the Birmingham Alabama area?

Thanks everyone!

[ELCIDd90]

:mad

I have had overheating issues with my D90 since I bought it. I have had the dealer and independent rover shops address this problem. I have had the radiator replaced at least 3 times and the head gaskets replaced once. This last round of problems occurred this summer. The radiator was clogged, and was re-cored. overheating has always been an issue, what should i do? I want to run a full check of the cooling system and engine sometime soon. What should I look for? So far I'm planning a full check of the radiator, fins, hoses, and the head gaskets? What else should I take a look at?

thanks ahead of time for your advice

Z

[Mike Hippert]

When does it overheat? On the trail, highway, in traffic? The water Pump, T-stat and temp gauge would be good to check also. T-stat is cheap to replace. Put in an after market gauge the rover units are crappy. Check the water pump to see if there is anything coming out of the weep hole.

When it overheats turn on the heater, If it blows cold air then you have lost coolent folw. If you don't have flow then make sure you have plenty of fluid. While it is still hot (engine off)feel the top and bottom radiator hoses there should be a differance. Also the top hose should be so hot that you cannot touch it.

[Gkase]

depending on its status it will cause intermittent overheating...mine did...
I don't know how to check it, see elsewhere for that, I replaced with electric fans.
George

[Buckon37s]

It should spin freely when you push it back and forth with your hand when the engine is cold. Like pushing it through molassis. When it gets real hot. Turn off the engine and you should not be able to move the fan with your hands. The fan clutch is heat activated. When mine busted it was on all the time.

[Mike Hippert]

When mine died it started leaking, and no matter how hot it got i could always spin it by hand.

[mikeslandrover]

Rads seem to clog internally. I'm planning to change my rad out this week end hoping to cure hot running when on the motorway. running at allother times is fine, the temp just creeps up when cruising at 60 mph plus.

[MiniGuy]

Just wanted to update my overheating situation. The radiator was clogged and I replaced it along with fresh new hoses and a new thermostat while I was at it.

No more overheating, so I am happy . . .. . .. but. . . . .now there is still a problem that I had hoped would have been fixed when the overheating issue was fixed by replacing the radiator.

After the engine has been running for a while, if I turn it off, the starter motor will not work until it has cooled down. Has anyone else ever had this problem? It is not a big deal if I am going somewhere and plan to be there long enough for the engine to cool, but it is certainly annoying to have to park on a hill or carry a couple gallons of water to pour over the passenger side manifold to cool down the starter motor.

Do you guys think that my starter is just going bad or is there something else that would cause a starter motor to refuse to turn over when hot?

[Mike Hippert]

My Starter did the same thing before it finaly died.