6.2 runs hot at highway speeds
 

Looking for suggestions here...When I am running above 70 mph or so, especially with heavy throttle (e.g. against a strong headwind and a/c running), my 82 6.2 starts running hot. I dont let it get to the overheating point, but it has gotten close. I have changed the thermostat, and recently changed the water pump, but the issue remains. Is this an issue with the 6.2? What does everyone think that flushing the coolant system would buy me? As a side note, it has been hot in SE Texas lately (95 deg or so and 90% humidity), but that is not unusual. I hate to think that I cant run at highway speed with no a/c because of a 6.2 issue.

check clutch fan

check radiator for pin hole leak, and rad. cap.

clean rad

Thanks for all the suggestions. I dont think the clutch fan was bad, but changed it out anyway. The coolant was a little different story. When I took the cap off, the coolant looked good and green at the opening. But when I drained it, the stuff looked like crap coming out at the bottom. I have only driven it to work this morning after flushing and refilling so I dont know what the final result is going to be, but I cant help but think it will be better.

over heating
 

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.

I fixed mine by:

1, Back flushing engine 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.