Engine overheating

[brianmef]

Hi everyone, I have a question that I might know the answer to already, but just want to confirm it with your thoughts and answers... I have a 2002 Mustang GT that I bought brand new, and this summer when it was hot out, driving with my A/C on and in stop and go city traffic, the thermostat goes to about 3/4 the way over and the A/C turns warm. Normally the guage is exactly half way. Up until this summer I could use the A/C in city traffic and the guage would never go past the half way mark. Now the engine over heats, and it did today with the temperature at only 77. If I turn off the A/C, the guage goes down pretty quickly, especially when moving. My fan runs like it should, so it's not a fan issue. Is it possible, and I'm guessing that it is, that my thermostat isn't opening up all the way? I've heard of thermostats sticking totally open or closed, but is it possible that it just isn't opening all the way? It won't overheat going down the highway with the A/C on, but in stop and go traffic, it overheats.


Thanks...

 

[02nightmaregt]

When did you last chang the t-stat?

 

[brianmef]

I have about 86,000 miles on the car and never changed it yet. Would you say that it's time to change it?

 

[02nightmaregt]

yea try that first

 

[blackink00]

also check to see really quick if the fins in the radiator are clogged with debree

 

[GettinThere]

Since you are changing the t-stat, of course also flush and refill the coolant, and add a bottle of Water Wetter.

 

[evil281]

how much is a t stat?

 

[GettinThere]

how much is a t stat?

I dunno, maybe about $8, can't be much. I got a Stant 180 deg t-stat years ago, seems like it was about $8.

 

[brianmef]

I bought one today at O'Reilly Auto Parts and it cost about $10 with the seal. The brand is Murray Plus, and is all O'Reilly had, which is OEM at 195 degrees. I've changed thermostats before on older cars and they had a seal that you place between the housing and the engine block, and the bolts go though it. Not this one though... Apparently newer engines are different and they have a rubber O-ring seal. I thought that was strange, and didn't believe it, so I went to another parts store and they told me the same thing, that there is just the O-ring seal. I'll be installing it in about 2 weeks probably as I don't have the time right now. It's not so bad that I have to do it right now, but I sure hope that this solves my overheating problem when I do. I will reply to this if replacing the thermostat resolves the issue, and if not what I did, so that others with this same problem will have the answer they need. I sure appreciate all of your feedback!