on a 400 mile trip to fla last week, my 99 4wd 4dr blazer started running hot (over 210) with a/c on. shifted funny a couple times when hot. ended up replacing fan clutch and t/stat. fanclutch was definetly bad, still gets hot though on long runs at high speeds with a/c on. trans fluid is a little discolored,did i cook trans by running it hot? added a qt of trans fluid helped temporarily. should i have tranny flushed? or just try changing filter or both?

great site.

 

Just change the fluid and filter....

 

doestrans fluid condition affect temp that much?

 

Is the thermostat the factory 195* one? Was it REALLY HOT outside? Those temps wouldn't surprise me under the right conditions.

 

The transmission fluid condition shouldn't impact the engine temps much... If the fluid was old and broken down, then it may cause excessive heat in the tranmission which will be partially passed off to the engine cooling system.

And yes, if it was hot outside and you had the a/c cranked, that definitely will have an impact on the cooling capacity of the radiator.

Really, 210*F isn't all that bad. Both of my vehicles normally run around 200-205*F on the stock 195*F t-stat.

 

ran 195* on freeway, got off on exit, tempjumped up to 230*. let it idle with heat on came right back down to 195*.had firestone look at it, gave it a clean bill of health.$25. will change trans filter & fluid and post my results. im open to any suggestions.

 

I'd start by cleaning the exterior of the condenser and radiator out with a garden hose. May just be bugs and other debris built up in the condenser and radiator.