Good Morning All,
I am out of idea's.
I have a 2000 Silverado with a 5.3L. I have owned it since new and it has 195 K on it. I have towed multiple types of enclosed trailers and boats with this truck over the years from 1500 lbs to 7000 lbs and have never had an issue.
Three weeks ago I had my boat on the back and noticed it was getting hot( 245 ), while towing on flat highway doing 55 mph.
After spending $2,000.00 with mechanics the following items have been replaced:
1) new rad
2) two new therms
3) new water pump
4) System flushed twice.
5) New fan(went to heavy duty fan clutch)
6) Block Test(passed)
7) Pressure Test( passed)
8) No coolant in oil.
9) No sweet smell in exhaust.
10) Only overheats while towing.(Has never done this before)

Anyone know something that I and multiple mechanics may not know or have checked? Please help. I love this truck.

 

I've NEVER had any luck with ANY aftermarket fan clutch. If it's not the bone-fide Chevrolet replacement part, you're gonna have trouble. Promise.

Allan

 

Understood. However, If it was the fan clutch, would it not over heat when at a stop of city driving. I believe after 40 mph that the air flow overrides the fan anyways, correct?

 

If your air flow is not restricted and you have replaced all said parts the only thing left is the TOC or transmisssion oil cooler which is inside of the end tubes on the passenger side. That said you may be overheating the transmission while towing and the radiator can't cool engine and the transmission. Check your trans fluid for a burnt smell and color. If their bad I'd change fluid and filter and add a trans cooler. Have 2 Silverado's with same engine and transmisson and have had to add a cooler for my towing