4.6 Thermostat replacement

15 mins max. Unless bolt is hard to get off good luck

I had a 180 degree thermostat in my GT.



I think it might cure your over heating deal.


Good luck either way.

i had trouble getting mine to mount in right. The two straps that run from the mounting area to the bottom were too far out. Ford makes their straps come in a little closer. That was my only prob.

To me, using a cooler thermostat to cure an overheating problem is like using duct tape to patch a tire. It might work for a while, but isn't going to fix the problem.

You should figure out what the real problem is. When does it get too hot? At idle? At speed? How are you judging this, by the stock gauge?

195 isn't too hot to be running, and any adequate cooling system should easily be able to keep the coolant somewhat close to that (195-220ish)

He has a 4v the thermostat is not in the same spot as our 2v there is a thermostat housing mounted inline with the radiator hoses.the thermostat on the 4v cars can be done with the hoses in the car it's just not as easy as on the 2v

BTW this is very very very very very very very important. make sure when filling the system back up you remove the plug at the top of the metal tube that runs in front of the intake, then fill the system there. If you don't do this you will have a nice giant air pocket and the system will not bleed.

so fill the system at the degas bottle then pull the plug on water bypass tube then fill there, then reinstall the plug and start the engine, use the vent with the heat on max and feel for heat at idle, if you have no heat then rev the motor to 2000 rpm's or so to break up the air pockets then you need to CAREFULLY loosen the plug on the water bypass and add coolant there and then top off the degas bottle. keep doing this untill you have steady heat at idle

architecthec said:

Thanks to all that responded. I took the advise of Twistedoffpurp and replaced the thermostat. I ordered the 180 stat at AutoZone and then got home and saw how easy it looked to replace and confirmed by Four Six - 2 bolts and fifteen minutes. I went back and bought the in stock 195 stat, installed it and everything seems fine. I ran it at idle with the cap off for about 30 minutes. The fan came on after about 20 minutes at which time the gauge was between M and the A in NORMAL. I shut it down and topped it off. Went for a ride and it stayed around the R and the M. I topped it off again after the ride.
I wish I would have known about the removable plug on the bypass tube. I saw it but did not think it was removable -dugh. When I ran it without the cap at about 2krpm no water came out but it looked like some water movement. At 3krpm it did throw water out. Does that mean my water pump is weak or was 2krpm just not enough to push the water that fast?
Sorry for the long post.
Thanks again to everyone.

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Am I reading this correctly? You didn't add fluid through the crossover tube?

If that is the case you need to fix that ASAP!

Here's the method you should use to fill your coolant on a 4v:

position your climate control to full hot.

Pull the cap off the crossover tube and the cap off the res.

You fill via the crossover tube until the fluid in the resevoir is all the way topped off, then you cap the resevoir and continue filling via the crossover until the crossover is topped off.

Then you run the car until it is hot enough to have the thermostat open, you let it run for a bit longer(I waited until the temp gauge went into the middle).

then you shut it off and let it sit over night.

Check the res in the morning, if it is still topped off, pull the cap off the crossover, if its lower then when you left it, top it off and start over...if its still full then you are done.

Also, some tips on the crossover plug, they can be PITA so we had to use a manual hammer driver and a torch to get the plug out...don't heat the plug so much that it melts the paint though. Then when you reinstall the plug add some anti-seize to the threads.