vdo water gauge install and 210 fan info

[Davis]

First, let me say that when I use the "search the site" box it takes me to a "page not found" screen, so my apoligies in advance for if this was covered.

I had just finished the install of the 210 fans and a performance 4 core radiator. On my trip to Home Depot today, the fans never came on--things look better for the cooling of my 4.6 now. I did run each fan through it own fuse, then through a relay which is back up on a 30 amp circuit breaker. I have an override switch installed in the cab, too. Which brings me to the VDO install.

I am probably going to get the VDO vision 250 degree water temp gauge and need to figure out the sender. I am currently using the thermostat sender to switch on the fans. I know others have done this, so where do you put the water temp sender and what size do I need to order up.

Thanks,
Chris

[Mike Hippert]

Yeah the search this site box is no good, use the search button in the blue nav bar, it searches the forum. As far as the sender goes, I installed an auto meter 250 temp gauge in my 90, I used the stock sender. Not the 2 wire AC sender the other one that only has 1 wire. I pulled the old one out and put it and the new one in a pot of water, I hooked the gauge to a 12 volt battery, I then slowly brought the temp of the water up, I connected the stock sender and the new sender that came with the gauge, they read and tracked the same, I also had a cooking thermometer in the water at the same time and it also matched. I could not use the new sender because it did not have the correct thread to go in the stock location.

[Hans]

Mine actually has 3 stock senders in it already (94 3.9). On the top left of the intake manifold is the ECU sender, in the front right of the intake manifold is the gauge sender. The thermostat housing has the sender meant for A/C which can be used for the fans.

-Hans

[Davis]

Looks like I could use the gauge sender in the front of the intake, then. Does anyone know the thread? I know the thermostat thread is the M22 1.5. Thanks.

[Hans]

Definitely smaller than the thermostat sender. The gauge and ECU senders ALMOST look like they are standard GM parts, or at least compatible.

The prices are cheap on those, so it can't be Lucas

-Hans

[Davis]

The sender in the 94 3.9 is a 5/8" x 18 thread. I got the 1/4"-27 VDO sender from Napa for $13 and then the autometer kit that has a conversion which I got a checker for $8. Have not hooked everything up, but should work. I also boiled the stock sender and the vdo sender and measured resistances and they are very different--in other words, the VDO temp gauge won't work with the stock sender.