my 1990, 6.2 runs 190 - 210 all the time at normal driving. when i hook onto a trailer it trys to run hot. maybe 235-240. any ideas on how to cool it better when under a load? I am going to flush the radiator this week and see if that helps but im not sure if that will solve the problem.

---AutoMerged DoublePost---

i have seen some post on here about a duramax fan clutch. would that help? If so do they interchange with the same waterpump? how would i go about getting the right fan clutch to fit my truck?

 

I run my 6.2 in the texas heat 105 f some days..... same problem, over heats on highway.

These engine need a squeaky clean cooling system to run at normal operating temps.

Remember its an old truck with many miles under the hood , prob never had the cooling system flushed.

I fixed mine by:

1, Back flushing engine with clean water until clear water came out.

2, Added engine flush, and ran engine for 20 mins. Then let cool down and back flush again you will be amazed at the rust scale and calcium that comes out...on the second flush.

3, filled up with fresh anti freeze mix, runs cool now at highway speeds 185-195....before 210-220.

Made a big difference. I replaced water pump and fan clutch, all it needed was a good old cleaning.

 

take the radiator out and fill with scrubbing bubbles leat soak for 30 minutes then rinse and easier on old radiator than them cooling system flushes

 

have you ever replace your t-stat? could be stuck, you can try and find a dual or triple core raditor for it, those always help