Thermostat installation

cyoder

Registered User
So im trying to install a new 180 degree thermostat and so far its not as easy as you would think it would be. What is the easiest way to put it in since it does not lock in place? Also, i tried going back to the original thermostat so i can drive it, but it leaks out of the bottom. What is the easiest way to get these gaskets to seal up?
 
Put a a little rtv on the cbore in the tstat housing, put tsat in housing, and let dry for a little bit. I like to put copper RTV on both sides of the gasket then bolt in place and let dry over night.
 
Ok i did all that and it finally sealed, but my question is how long should it take to warm up the car. I ran it for five min with no leaks, but it didnt get very warm. The little valve is at the top of the thermostat as your looking at engine. With brand new head gaskets i dont want to take any chances. If its stuck open is it still driveable for the night?
 
Actually strike that i went inside for 2 minutes come back out and the car was really hot, but only reading to the line above the c whats that mean?
 
Actually strike that i went inside for 2 minutes come back out and the car was really hot, but only reading to the line above the c whats that mean?

It probably means your sending unit is FUBAR (as are most one-wire sending units from Ford until about 1995 ... )

The gauge uses the one-wire sending unit, the EEC uses the two-wire sending unit.

There's actually a TSB on the sending units (been posted here several times, search if you want to read it), but I'd just swap it out, with some teflon tape to seal it.

RwP
 
Actually strike that i went inside for 2 minutes come back out and the car was really hot, but only reading to the line above the c whats that mean?

On my car that position on the gauge is right around 185 mark or so. Those gauges have a narrow operating range, as on mine 200 degrees puts the gauge just above the N and 210 is in the middle.

You have to be aware though, that your low speed fan won't come on until that gauge is along way up, because the stock "tune" is setup to bring it on at 220F. The only "correct" way to fix that is to get a chip. Normally when setting up a tune we set the low speed to come on at 190 or so with a 180 tstat. Sorry to say this, but running a 180 tstat without a tune to compensate for it with the fans is not an optimal setup and could possibly end up with a hotter running engine than before.

But as mentioned above, the stock gauge setup sucks and is not that reliable. I know by reference what the temps are, but I've seen other cars that have the gauge a lot higher at the same temps.

Fraser
 
Ok so i put a thermostat gun on everything to see what it is reading. The thermostat itself was reading 205 which was about when the fan kicked on and that was at the n on the gauge which is the highest it has been. The water pump read 198 degrees and the radiator read 203 degrees. Does that seem right or is that way high? I literally just got new head gaskets put in (thanks to cmac89) and i really dont want to overheat the car. At what temp is when its starting to overheat?
 
Those seem like pretty reasonable operating temperatures. Everyone obsesses about cooling down the intake charge but higher temperatures encourage engine efficiency. It will also impact emissions.

I can't imagine it being unsafe for your head gaskets, at any rate. FWIW, on my other car with custom fans, I have them kick on at around 195 degrees.
 
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Those seem like pretty reasonable operating temperatures. Everyone obsesses about cooling down the intake charge but higher temperatures encourage engine efficiency. It will also impact emissions.

I can't imagine it being unsafe for your head gaskets, at any rate. FWIW, on my other car with custom fans, I have them kick on at around 195 degrees.

Our motors detonate all the time. Higher temperatures lead to more detonation which lead to blown head gaskets. The sweet spot is around 190-200 for them.

You mentioned intake charge which is a different topic that what is being discussed which is coolant temperatures. High intake temps will cause detonation even more... why do you think Ford starting yanking timing out at 120F ACT's and by 180F it was at a full 8 degrees timing being pulled. I can also assure you that on a stock setup at around 145F on most of these motors the knock sensor was also kicking in and pulling even more timing for a total of 16 degrees being pulled out. It would only take a few seconds at WOT to have this happen.

In an ideal perfect world, which we know the SC's do not fit in, higher temperatures means more efficiency, but we don't have that luxury.

Fraser
 
Ok so i put a thermostat gun on everything to see what it is reading. The thermostat itself was reading 205 which was about when the fan kicked on and that was at the n on the gauge which is the highest it has been. The water pump read 198 degrees and the radiator read 203 degrees. Does that seem right or is that way high? I literally just got new head gaskets put in (thanks to cmac89) and i really dont want to overheat the car. At what temp is when its starting to overheat?

Do you have a chip in the car changing the fan on temps? If not, then the fan came on at 220F unless your ECT sensor is pooched and reading too high and telling the EEC the wrong temperature.

Fraser
 
Could be. I'm no expert in these engines. I can say that in my experience combustion chamber configuration has more to do with preventing detonation than just about everything else.

205, if correct, seems pretty close to the sweet spot that you mentioned.
 
Could be. I'm no expert in these engines. I can say that in my experience combustion chamber configuration has more to do with preventing detonation than just about everything else.

205, if correct, seems pretty close to the sweet spot that you mentioned.

Thats the problem with these heads..... they suck, period, but we're stuck with them so we work around them.

As I mentioned earlier, the stock tune has the fan coming on at 220F, so if everything is working as it should, then when the fan came on his motor was at 220. The high speed mode of the fan comes on at 228F. That is way too hot for my liking for any motor because that sure does not leave much room for error there. Especially since we do have "dead" zones within the heads with no coolant flow.... so the coolant is boiling there.

Besides, using a thermal gun and reading surface temperature is not a very accurate way of doing things... too many variables. The ECT sensor is about the most accurate your going to get on the motor, besides a good aftermarket gauge.

Fraser
 
No i dont have a chip in my car as of right now. Something else that happened yesterday on my lunch at work was that the fan kicked on as soon as i started the car and ran the whole time i was on lunch.
 
Did the fan sound really loud.... if so then for some reason it sounds like the EEC went into limp home mode because of a sensor failure. Can you read any codes from the EEC?

Fraser
 
Ahem.

My factory setup on my 1991 was to be at "N" when it was steaming due to a bad radiator.

Swapped to a new sending unit, and now it sits between the "O" and the "R" with a 195F thermostat in while boogying down the highway at 65MPH in 101F heat with the A/C on.

(Got to the right bar of the "M" sitting in traffic in 101F heat with the A/C on ... which is OK, IMO. Have yet to properly adjust the antifreeze level - just swapped the thermostat housing on the 5.0HO and am still mostly distilled water.)

RwP
 
In my 90 and my 92, the temp gauges read straight up between the O and R (even with the AC on)....

The low speed fan kicks in when the needle hits the left leg of the M and high speed kicks in when it hits the right leg of the M.....

However, I have noticed something I think is weird...

It seems to take a long time for the temp to come up to normal....:confused:

I can get on the interstate and drive for 30 miles or more at highway speed and the temp barely gets to the N.....

If I have to slow down for traffic :mad: then the needle will go to the straight up position and stay there, even after I get back up to highway speed.....
 
I just bought a new coolant tenperature sensor today so i will put it in in the morning and see what happens from there. Im kind of confused on how there is a temperature sending unit right by the thermostat and then there is the ect sensor by the dis which is the one im replacing.
 
However, I have noticed something I think is weird...

It seems to take a long time for the temp to come up to normal....:confused:

I can get on the interstate and drive for 30 miles or more at highway speed and the temp barely gets to the N.....

If I have to slow down for traffic :mad: then the needle will go to the straight up position and stay there, even after I get back up to highway speed.....

Wonder if your thermostat may not be hung open? That would cause it to be slow to warm up.

RwP
 
Coolant temperature is switched out, and car got all the way to the n on gauge while driving, but sitting in my driveway it only got to the line above c. Fan did not kick on at all so maybe that fixed it.
 
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