ok, thanks guys. I'll try those things tomorrow. I have a long trip ahead of me and need to get this figured out.

 

Now I'm thinking I should just have my local mechanic install a new water pump and thermostat. I wonder if I should have him install a new fan clutch as well while he is at it?....because my AC does not blow cold at idle. (only under load)

 

The A/C issue is more likely a refrigerant undercharge.

If you don't have the ability to test your fan clutch, your mechanic should be able to.

With the engine OFF - the fan should spin quite freely with a cold engine, but if the engine is hot, it should be quite difficult to move.

 

By hot do you mean normal operating temp or when my temp gauge pegs? I'll test it right now.

Ok I tried to spin the fan with engine cold, it does turn but only a few inches before stopping...seems a bit stiff. Is it supposed to spin a few revolutions?

Now I'll drive it to the hill with a steep incline and when the temp gauge pegs I'll shut off the engine and try to spin it.

 

I'm back from my test drive. When my temp gauge pegged I immediately stopped the truck and tried to spin the fan. It actually spun easier than when the engine was cold. Can I now safely assume that I need a new fan clutch?

 

Yep! With a pegged temp gauge it should be almost completely locked up.

Another option would be an electric fan conversion.

 

Sweet! Thanks! You guys are great.

 

There is alot of things that can cause a problem. Glad you got it figured out! I was thrown off by the gauge going back to normal after a key on/off.
Good call GLC

 

That's because the gauge is more of an idiot gauge than a true gauge. As the engine warms up, it slowly climbs to about midpoint. It STAYS there till a certain temperature (definite overheating) is reached and then immediately pegs. When the temperature drops below that exact point, it goes right back to 1/2.

 

Yeah but his lazer readings are so close to mine and I'm not remotely close to overheating. Crazy... learn something new everyday. Thanks.

 

I'm sure I wasn't pointed at the ideal spot with my temp gun. In my mind the actual temp was somewhat irrelevant. The change in temp during the event was what I wanted to capture. I realized I could trust the cylinder head temp gauge but it was slightly behind the the actual coolant temp. The no AC at idle was a big clue I missed.

 

Just thought I'd post back to say that replacing the fan clutch solved my overheating problem and I also have AC at idle now too.