Just popped up when I was towing...it's done it twice now.

Around the city, in traffic, whatever, I have never seen the temp go over 200 or so....the gauge is always one tick below 210. When I towed our boat this weekend the temp got up to 235-240 pulling uphill, but it's weird how it did it. I thought it was a problem with the fans not turning on like they are supposed to at first, but I have messed around with them a little bit and they seem to be working fine.

When I start up hill, the temp stays where it's supposed to be for about a minute or so....then starts to quickly creep up to 235-240. When the ground levels out and I cruise without much of a load, the temp will drop back down to where it is supposed to be within 20 seconds or so. Ambient temp was 100 degrees the first time and 80 degrees today.

My radiator was brand new when I put it in, still running Dex-cool, fans are fine....the only thing I can think is that maybe the thermostat is going bad? Truck has 93,000 miles and original t-stat. If that's not the case, is it possible that the 34" radiator can't keep up? I can't imagine that's the problem, I never had a problem with cooling when the clutch fan and 28" radiator were in. I suppose it could possibly be a problem with the fans because I can't tell if they are on or not when I'm driving, but every time I have gotten out to check if they are on everything is fine.

 

how long ago was the install. sounds like air in the system. when you start uphill it isnt letting enough coolasnt get to the engine maybe and causing it to overheat.

 

I would change the t-state just for piece of mind. My gauge always shows slightly hotter than it really is. about 10-15 degrees hotter than what the scanner shows.

 

Air pocket would be my guess too but I would also change the t-stat out for a 160* just for the heck of it anyway.

 

How do I get rid of an air pocket if there is one?

 

Can you tell if the fans are going into high when the temps get hotter, or are they staying on low.

 

you have to bleed it out sorta like a brake system. when i've bleed a coolant system there were little brass fittings in the system that you can open and close you would run the vechicle to build pressure then crack the bleeder open and it would alow air out.

 

I'd be thinking possible air pocket...or like desTRUCKtive mentioned, maybe the fans need to be running at a higher speed.

 

You can go through a few heat cycles with the overflow cap off.

 

I've had pretty good luck at keeping away from air pockets by squeezing my upper hose during the fill process...you can actually hear it gurgle in the overflow.