I recently bought a 2002 H1 with a 6.5L and it is idling at 500 RPM which is causing the oil pressure light to come on at idle. In the summer this rig ran super hot on the highway. (nearly in the red at 65 mph for 15 minutes)

I'm curious is this might be something to do with the #8 issue typical with the 6.5 or any upgrades that might increase power and eliminate some of these issues. Any help would be great!

Jay

 

All 2002 models had the GEP heavy block so you shouldn't have to worry about the number 8 cylinder issue.
The way the cooling stack is set up on the H1 check to make sure all the fins on the radiator to make sure there isn't mud, debris in there.
Also most H1s will ruin hot in the summer at 65 mph, especially if you are going up some grade.
Obviously check the normal thinks first, coolant level and whether it is still good.

 

3Hummers,

Thanks for the reply. Will double check the radiator, we have been playing at the sand dunes of Little Sahara and it's possible that we need to clean some sand out of the radiator fins.

Any suggestions on power upgrades?

 

The 6.5 TD motor just isn't upgrade friendly. You can't do anything to get big horsepower gains. Some people sell upgrades that they claim get big gains but even the guys racing SCORE in H1 race trucks can't get big horsepower out of the 6.5. Don't believe all those claims of 100+ HP gains. There is no testing data that has been made public to back them up.

 

2 inch lift and an intercooler will help HP
I agree, the Predator kit for my 97 didnt do much at all.
Time for a Cummins.