[MykD]

My wife says, and I quote, "You need to sell that truck. It's like you're dating a whore. You're not getting anything in return from her. She's pretty on the outside but she has AIDS or something else incurable." I told her my girl is too hot for me to give up on.

ROFLMAO!

(Background) I have replaced my waterpump, thermostat, every single hose, reservoir cap and bypassed the heater core since I'm in SW Florida and it was leaking, and my baby is STILL running hot.

So, I'm wondering if it could be the fan clutch. She idles in the driveway and gets up to running temp and stays steady but as soon as I get on the road the needle goes up. The fan doesn't spin excessively and has a "fluid" resistance to it when the engine isn't running. It spins and seems to engage. Any clue how to diagnose if it's bad? It's my last resort before admitting I've blown a head gasket.

Any idea how to diagnose if it could be the fan clutch?

 

[redtruck12]

Doesn't make sense that it would run hot at speed if the fan clutch was bad.
I would expect the opposite.
I would flush the crap out of it. Fill it with a proper mix of good quality coolant, maybe a water wetter additive and follow the bleed procedure to a T.
180 thermostat?

 

[jhmover]

My 96 ran hot at speed. New fan clutch solved it.

That being said have you pressure checked it? They have plastic radiator tanks, could be a small crack letting out pressure.

Also could be a head-gasket or slipped liner.

 

[number9]

From WM:

Remove drain plugs from LH and RH sides of
cylinder block and allow cooling system to
drain.

Have you removed the block drain plugs and flushed out engine cooling passages? Sometimes gunk collects in there and can cause cooling issues. Plugs can be a PIA to reinstall.

......

 

[nrkmann]

Fan Clutch diagnostic:

Correct: Spins free when cold, engine off. Easy to stop the fan (well gloved hand) with engine running at idle.

Correct: Will not spin when hot, engine off. Fan can't be stopped or is very very difficult to stop with the engine running at idle.

Incorrect: Fan has any free spin when hot, engine off.