too hot at idle, too cool on highway

[towser42]

Hello, folks. I have a '93 with a 1.9L engine, 91,000 miles. If I leave the car in idle for 15 minutes or so the engine get pretty hot -- no overheating, but the needle on the guage shows the high-side of normal. When I'm on the highway the needle is only slightly above C and very little heat comes into the car, even with the heater set for full up.

I did a flush and fill recently, but it didn't help. I also changed the timing belt recently and the water pump seemed to be working fine. Any ideas would be helpful.

Thanks

[pmaloney]

so your fan is working, right?

Did you change your thermostat? I'll bet that's what it is.

If it's not that, it might be a coolant temperature sensor acting up or something....but I think it sounds more like a thermostat.

[towser42]

OK. Back to the Haines book to find the Thermostat! At least the thermostat is pretty inexpensive.

Thanks,

[pmaloney]

Good luck. Thermostats are generally pretty easy to replace, so I don't think you'll have any trouble.

[towser42]

I just finished replacing my timing belt so the difficulty factor isn't much of any issue for me, but I'm just tired of spending so much time under the hood of the @#$@#$@#$ Escort! :-)

Thanks,

Peter

[bkw]

i have the same problem with 92 escort. i have replaced the thermostat and the coolant temp sender and radiator.the fan works when i turn on ac so i know thats good. cooling fan relay seems ok. if i turn on the key and push the relay arm the fan works.
where do i go from here.
thanks in advance.
bob

[Snow93]

watch that thermostat when you go to remove it.. aint nothin like strippen treads... when i went to take mine out the bolts were so bloody corroded had to get a shop to do it..

[escortracingsc]

The Ford Escort has what is called a Vapor Bypass Valve inside the Thermostat housing. If that valve fails it will cause the car to run hot or run cold, depending on conditions. The reason is that the coolant is allowed to bypass the thermostat when that valve fails, this can cause it to over cool in the winter time and over heat in the summer time.

The way to tell if your thermostat housing is bad is to take it off and shake it, it you hear something rattling inside of it the valve has failed, a junk yard seems to be the only place to find a replacement housing, no aftermarket onse are available, and delership prices may be prohibitive.

My car ran cold when I got it, Turns out the valve failed, AND the thermostat gasket slipped off allowing constant coolant flow, engine didn't warm up, I got no heat. Didn't bother to much in winter, but then summer came around and even with the fan running on highspeed it could not cool the engine enough, additionally because it was running hot the computer would not allow the A/C compressor to come on, and I was hot too!!!

Maybe this will help someone with their pwoblem...

[willye]

Tell me, what if you plug the Vapor Bypass Valve inside the Thermostat housing to eliminate the bypass of coolant? I did this recently and it seems to make little difference.