Is my thermastat going bad?

[svteet93]

Lately when I get in "stop n' go" traffic my temp starts going up pretty fast. I can hear my electric fan kickin in but that doesn't seem to slow it down much. I also have a 3 core aluminum radiator and this is on a gt40 fms crate motor(new water pump) Im also running underdrive pullies but I bought this car 2 years ago with all these mods and had no probloms...any suggestions?

 

[modusmortis]

once your car is warmed up you should *carefully* feel your upper radiator hose. If its relatively cool then the t-stat is stuck closed. Otherwise I would suggest radiator blockage.

 

[SVT32VDOHC]

Sounds like you have a great set for your cooling system. I would replace the T-stat and see what happens. They could cause you car to overheat or not get enough heat. I just replaced my girls the other day on her Escort, she had a no heat. After 20 mintutes of installing the new one, I drove the car around and it had a good engine temp and great heat!! Give it a shot.

 

[HISSIN50]

I'd agree about the T-stat, given the info provided. I like the Mr Gasket line of t-stats (they make parts store stats look like crap).

I'm wondering if you are using a real temp gauge (I thought perhaps not) - this would be a time to install one if you have the desire.

If this is only in slow traffic, check the fan

Good luck.

 

[5.0 Nostalgia]

Remove the t-stat and toss it in a pot of boiling water. If it doesn't open, it is bad. Either way, I would replace it with a new one while you have it apart. But at least you will know if that was your problem.

 

[HISSIN50]

One caveat about the boiling water test - not a disagreement but point of clarfication/emphasis.

I'd note that the boiling water trick won't often show a damaged pellet. Air pockets under pressure will destroy a pellet quickly - the stat is out of calibration and unreliable thereafter.
The pot of water test is nice and if the stat fails, you know you found an issue. But if your stat works fine in those rather calm conditions (on the stove), that doesn't mean it is performing properly in the more aggressive environment inside the t-stat housing.

 

[5.0 Nostalgia]

That's a good point. Are you saying that the boiling water test will cause a good thermostat to fail or that it may not necessarily show that a thermostat is bad because the conditions are different? I just used that trick one time to see if a new thermostat that I dropped worked. Does that mean I ruined the new thermostat by putting it in water or that it may not have shown if it broke when I dropped it? I am just wondering for the future.

 

[04sleeper]

I also would recommend changing the thermostat. I would try the Mr. Gasket 180 degree high flow.

You may find out that it may not solve your issue but it is cheap insurance and if you are having trouble with your cooling system, now would be a good time to replace it anyway.

 

[HISSIN50]

That's a good point. Are you saying that the boiling water test will cause a good thermostat to fail or that it may not necessarily show that a thermostat is bad because the conditions are different? I just used that trick one time to see if a new thermostat that I dropped worked. Does that mean I ruined the new thermostat by putting it in water or that it may not have shown if it broke when I dropped it? I am just wondering for the future.

I'm sorry if I made a very simple point convoluted (I do it often). You have the right idea - the boiling water test won't necessarily show that a t-stat is bad because it's can't simulate all the conditions the t-stat sees. It's like testing an ignition coil - you can have a spark plug set on top of the intake manifold (that's how test spark) and it will spark decently. But once you put the plug back in the chamber and toss fuel and compression on it, that seemingly good spark might go bye-bye (even though my bench test was good). I don't know if that made sense or not (if not, forget I said it ).

You definintely didn't break your stat with the boiling water test - if it can't even pass that test, then you don't want it in your car. It's surprising how many new t-stats don't even open near when they should. You're smart to test yours before installing them.

Kevin and I run (in his case, ran since he drives a zillion HP machine now) the same exact stat. It's neat because it's balanced (there's a shroud around the pellet, which really helps protect it if air pockets or coolant start beating up the stat. Being balanced also meaning that it opens within a couple of degrees of when it should. Some inferior stats take ~15* under high RPM and pressure to fully open). It also flows better and has a jiggle valve. Great bang for the buck for a couple bucks more than a parts store version (Kevin and I live in the desert and do what we can to achieve great efficiency).

I'd note that when I went through the fox's cooling system, I had a new parts store 180. I ran it for one week (in 115*F temps) before going to a Mr Gasket 180. Apples to applies, right? The avg 'hot' operating temp of the car dropped 8*F just from swapping stats (per a mechanical gauge). That was pretty key to me.

Sorry for the long-winded ramble session.

 

[5.0 Nostalgia]

Thanks for the info Hissin50. I actually did get that Mr. Gasket 180. It was like $8 so I figured why not get the best unit?

Yes, your response made sense and was helpful.

 

[svteet93]

thanks for the info. Mr.Gasket 180 is what Ill try ...

 

[Jzava50]

i got a steeda stat ....is that a good one??

 

[tbovee]

Radiator caps are cheap too. I usually replace the cap with a new stat.

 

[white99gt]

ok so does it only over heat at idle?
If so its NOT the tstat.Its your fan.
What brand of efan do you have?