Some background I now live in Pheonix, AZ where it is hot. I anticipated the coolant system temperature to increase some but I have been pretty suprised as of late at how warm the temps are. First off, I have installed the 180* t-stat. It has never ran around 180* always more around 190*. Now that summer is upon us my wife and I took a trip into a cooler area and here that means climbing the I-17 towards Flagstaff which is quite the uphill battle. Before we reached the top my aeroforce guage said 257* then it was followed by a surge down to about 235*. Followed by another surge to around 245* and that was it wanted to stay. I then rolled the windows down turned on the heater and the temps went down to about 220*. This was all okay, I chalked it up to climbing that much elevation in 110* heat. Today coming from work which is 35 miles away on the very flat I-10, cruising at around 77 temps pegged at 228* but leveled off at about 223*.

My question being is my t-stat sticking or do I have a bigger problem on my hands? Anyone here from AZ.

The car is 2k bonnie with 141k miles and stage 1 upgrades.

Thank you very much.

Sounds like a bad ECT sensor.

Check in front of the condensor and radiator for leaves and garbage. try blowing the stuff BACKWARDS as to not blow it towards the radiator because that would cause the crud to go in deeper. and what is the coolant mixture? is it right at 50/50 or does it have more water than coolant? if so, the boilingf point is lower as it should hence having it heat up and making it harder to desipate heat. is your coolant cap good?

Just ideas to try to help you. if all the basic stuff is good, then we can move on to diagnosing the cooling system further.

Eric.

It is about 50/50, I have a small leak somewhere and about every 20k miles i have to add about 1/2 a gallon or so and I always fill with 50/50 DexCool stuff

ok. i would find that leak first. that will cause a system to run hot because it is not allowing the system to run under the pressure it should causing the boiling point to decrease / the temp to rise above normal.

If anyone else wants to put their 2 cents in, please do so.

Eric.

So if I can't see a leak, where would you suggest looking? Wouldn't that be like my water pump or the heater core?

Your leak could be running through the engine because of a bad LIM gasket. Does you exhaust smell sweet?

Once you determine the leak (could be UIM if you are not charged) there is another item available. A larger radiator.

If its that hot there u may even wanna look into some intercooler systems for the rest of your engine as well.

Is there a way to pressure test the system? Could it be in this heat that I am evaporating water?