So, I hopped in the disco and ran out to the store tonight. About 3 minutes in I stopped at a light, and smelled a really hot smell. It stuck with me as a left the light, but stopped about a minute later.

Then I noticed temps climbing 10* higher than they have in the same weather and driving.

Coolant level is right where it should be, and I get coolant under pressure immediately when opening the bleed screw on the T fitting.

I'm thinking water pump, but everything seems to be spinning as I would expect. The way home was relatively uneventful, other than temps hovering around 204(as opposed to 194).

I have a genuine cooler thermostat, so I doubt that stuck closed, but the ride in to work tomorrow could be eventful.

Thoughts?

 

My first thought was water pump, starting to freeze up.
I would check the idler bearings, water pump and the fan clutch.
FYI, I had genuine cooler thermostat, that stuck closed and replaced with 180* genuine thermostat and temps went to 189-194*.

 

I'm with Joe, sounds like the bearings in the pump. Go electric on the pump and rad fan, make a block off plate to go over where the factory pump is, and get a shorter serpentine belt to bypass that pulley

 

On second thought, looks like you have to have that pulley there unless you also delete the AC and go for electric power steering. Unless you're willing to do that, I say just replace the pump and belt.

 

In my experience, the belt lets you know when it's becoming faulty. Inspect the ribs and that's that, unless it's cracked or distorted in any way. Pull the belt and see if the motion or stability is suspect on the fan and water pump

 

After a day of driving, it works fine at freeway speeds. Go figure, forcing 70MPH air in the front. I end up around 200-204 in traffic.

I'm thinking this indicates it's not the water pump, so I looked up front at the electric fan. Little bastard isn't spinning, even at idle with 204 temps.

Looking in the Rave copy I have, it looks like the electric cooling fan doesn't come on until... 212*F? That doesn't seem like the fan could have been running previously. Can those settings be changed? Might something have been reset? No changes in power or operation on my part.

I haven't smelled the same smell I noticed that first time...

But something is different.

 

Anything slowing the belt is slowing the flow. Tensioner/idlers okay?

 

Viscous coupling on the fan DOA? It hooks up at idle, smells bad if it leaks or cooks itself.

 

not your water pump the truck would over heat instantly,
probably not your condenser fan either, at 70 mph the truck doesn't require any fan.
The condenser fan does not come on until 210 degrees.
i would look at your clutch fan and t-stat.

 

The t-stat is brand new, so I'm thinking the fan clutch is likely the culprit.