I recently was pulling my camper up up a 7% grade, 7 miles long and the temp gauge went up to the last mark before hitting 260F red mark.
I estimate the temp gauge was at 245F-250F. No engine overheating warning messages came on dash. I was doing around 40-45 MpH.
I got very concerned about possible engine or tranny damage
AFTER THE FACT
Once I topped the hill the temp gauge went back to normal.
It was in the high range for about 15-20 minutes.
The Yukon runs fine ever since that happened, and I learned I should have used manual mode and kept the RpM around 4000 to help cooling.
Do you think I should be concerned?
Short answer: YES!
Longer answer: I am a pessimist, certainly, when compared to the above.
The amount of money someone would have to pay me to let coolant AND/OR ATF temp REACH 230F -
nevermind exceed 239F -
would cover the purchase of 2 or 3 used GMT800s in serviceable condition ... JUST IN CASE.
At the bare minimum - say, you're an optimist, and you also rolled a natural '20' -
since you did not mention changing your motor oil / ATF / antifreeze
you should not only change them NOW, you may also want to analyze the used fluids to
determine any damages.
The balanced way of looking at this:
Ever see pics of prez obama before vs after presidency? He looks like he aged more than 8 years,
because he DID. admin, lean back, I'm not tryna get political ... HERE. Point is:
You DEFINITELY prematurely aged your engine transmission AND cooling system up that 7% grade;
you ought to change your motor oil / ATF / antifreeze IMMEDIATELY.
Next time, use Tow / Haul mode, AND avoid towing in 5th / 6th / 7th / 8th, especially uphill.
