So I've had this problem for a while and I've exhaused my options. The car is acting like it's got a stuck open Tstat, but I've replaced it twice. The car has a brand new tstat, rad, both rad hoses, rad cap, and a new tstat housing. I've bleed the system properly with the little bleeder on the heater core lines so there's no air in my system. When I'm going down the highway the needle on my guage stays pegged cold, rarely does it move, only when driving in town with a lot of stop and go, then it will move up into the lower portion, but it still says it's cold. If I let it warm up before I go anywhere the heat is mildly warm, but it won't cook you like any other vehicle I've ever owned. Latly the temps have been around 10-15* F for the highs and the lows around or below 0. Don't know if that's playing a role or not.

This only happened once, but while letting it warm up the system created so much pressure it started pushing coolant past the lower rad hose and leaking onto my tranny. I hooked up a pressure guage and let it run for 10-15min in the shop and it built 25psi. I bleed the cooling system again and did the same test for the same amount of time and it only rose to 13psi and it hasn't created enough pressure to cause the lower rad hose to leak again, but I'm still not getting much heat and the car is still not warming up properly.

I was thinking that the only way it could create that much pressue is if the head gasket was blown letting psi into the cooling system, but I ran a co2 test on the coolant and there was none present, and I'm not burning any coolant, or loosing any for that matter.

I'm stuck here, I don't know what else to do except for trying to replace the tstat for a 3rd time. Any other suggestions?

faulty temp sensor.... do the hoses feel physically hot/warm?

im with sam temp sensor if not the check the ground that goes on the thermostat housing if there is one but go for the temp sensor

Its the thermostat. I bet you were using auto parts store replacements. I went through 3 before I got a good one a few years ago.

A bad temp sensor won't cause it to overpressurize. I'd bet that there's still air in the system. Re-bleeding the system is easy, cheap and doesn't take long. You may be pleasantly suprised.

im with sam temp sensor if not the check the ground that goes on the thermostat housing if there is one but go for the temp sensor
There's no ground on the tstat housing, I thought about the temp sensor as well, but I havn't done that yet.

And I don't know if there's a difference in the temp of the hoses, it's to cold out right now for me to check after a drive -20* windchills and no garage don't mix well.

Its the thermostat. I bet you were using auto parts store replacements. I went through 3 before I got a good one a few years ago.

The first one I got was from Oreilly's and the second was from Carquest. Only reason I didn't go with factory is no dealer in my area stocks one and I didn't feel like waiting on the day I was doing it. I may try throwing a factory one in there and see if that makes a difference.

A bad temp sensor won't cause it to overpressurize. I'd bet that there's still air in the system. Re-bleeding the system is easy, cheap and doesn't take long. You may be pleasantly suprised.

That's what I thought too, that's why I've bleed it 3 times already and I'm still having the issue. It seems that the last time I bleed it it atcually helped out some, the first two times it didn't do anything. I may try and bleed it again when I get to work, but I really don't thing there's any air left in the system.

There's no ground on the tstat housing, I thought about the temp sensor as well, but I havn't done that yet.

And I don't know if there's a difference in the temp of the hoses, it's to cold out right now for me to check after a drive -20* windchills and no garage don't mix well.



The first one I got was from Oreilly's and the second was from Carquest. Only reason I didn't go with factory is no dealer in my area stocks one and I didn't feel like waiting on the day I was doing it. I may try throwing a factory one in there and see if that makes a difference.



That's what I thought too, that's why I've bleed it 3 times already and I'm still having the issue. It seems that the last time I bleed it it atcually helped out some, the first two times it didn't do anything. I may try and bleed it again when I get to work, but I really don't thing there's any air left in the system.


I might have an OE t-stat that I replaced (and didn't fix issue)... I'm pretty close, in Tulsa, I grew up in Shawnee... where are you in KC?

I might have an OE t-stat that I replaced (and didn't fix issue)... I'm pretty close, in Tulsa, I grew up in Shawnee... where are you in KC?

Sorry, havn't had a chance to get on lately. I'm in Parkville right off I-29 and 635 on the MO river.

man I can't find it.. let me look some more.