2000 Yukon XL Running Hot While Towing

[Rivieraracing]

So are you only running straight water or did I miss something? If straight water, just drain it and fill with 50/50 coolant and be done with it? If you already have 50/50 coolant in there, as long as you flushed if all out good with a hose ai don't see a reason to drain it and refill with new coolant unless it looks pretty dirty!
My denali usually always runs at a click short of the needle being straight up in center, and you did pretty much everything I would have done with replacing all the parts you changed out! Keep us all in the loop with your results!

 

[FlyboyTR]

So are you only running straight water or did I miss something? If straight water, just drain it and fill with 50/50 coolant and be done with it? If you already have 50/50 coolant in there, as long as you flushed if all out good with a hose ai don't see a reason to drain it and refill with new coolant unless it looks pretty dirty!

No, I also have a cleaner in the water. There was slimy build up visible in the overflow tank. Even the coolant that was in the drain bucket had a nasty film floating on the surface.

This morning I will warm it up, do a double flush...or as much as is needed and refill with 50/50.

During last nights outing, the temp gauge stayed 1.5 clicks below the center, 210 degree mark. I will be towing the boat in a couple of days and am looking forward to seeing how it does.