2014 GMC YUCON DENALI 6.2L w/factory towing package

William Conner · September 15, 2021

I'm towing a 24ft camping trailer; a Passport 197RB made by Keystone. When pulling long grades, most recently on I77 heading toward Boone, NC; the engine overheats to the mark between 210 and 260. As soon as the road levels off, the engine temperature drops back to the normal 210 degrees. This only happens when towing our camper. I've had the vehicle back to the dealer service 2x, but have not totally resolved the problem. They changed the radiator this last visit, indicating that a leak was found during a pressure test. No problems were found on the first visit, saying it was OK for the engine to run a little hot. Looking for any help (suggestions) for resolving this issue. Thanks much !!!

CamGTP · September 16, 2021

Just a FYI, the cluster does not read the actual coolant temp. In those year trucks the 210 mark is really about 195ish and you can prove that with a scan tool that reads live data. You are probably running around 220-225 when it does get hot pulling that heavy load up a hill. The dealership is right, it's okay to run that warm.

There isn't much you can do at this point. Running a cooler thermostat than the stock 194 degree temp won't solve much because even though it's a cooler thermostat, it will still cause it to heat up just as much under a long load situation like you are in. The cooling fans will still come on at the same temps and so on.

You're biggest problem is coolant flow and radiator size. Going to a much larger (thicker) radiator would help with engine cooling because there would be more capacity and more cooling fins to help remove heat.