To anyone who helps, thanks in advance....Here's the story....Sorry it's long, just trying to be thorough.

I just performed a major service on my '92 4x4 truck with the 3.0 and 159,000 miles. Engine was fully rebuilt by a reputable shop at 138,000.

Here's what I recently did:

-New fluids throughout (engine, tranny, diffs, coolant)
-New coolant hoses (belts were good)
-New fan clutch and fan blade (fan shroud and radiator were good)
-New spark plugs, air filter, and other small misc. tune up related stuff

I was driving it for the second time since doing all this stuff to it and it began to overheat when sitting at idle at a light. This was after I drove it for 6 miles to the store and I was on my way back home the next 6 miles. I got it home just as the temp needle hit the red. I popped the hood and saw the fan turning, plenty of fluid in the coolant reservoir and everything seemed normal.

I let it sit for about 5 minutes and then it was driving me nuts that it overheated. I started her back up and took her around the block again. tHIs time I turned the heater on high (thought there might be a air bubble in the system after the coolant flush) and the temp returned to normal. Then it rose again when I turned the heater off. I parked it and that's where I'm at now.

What do you guys think it could be? Thermostat and radiator cap are fairly new (within 2 years). Is there a good way to bleed the cooling system of air?

Thanks guys, I'm stuck and don't know what it could be.

-shawn

 

By the way,

The fan clutch turned very easily after I shut the engine off. Is this normal?

-shawn

 

Some times u can get a bad Thermostat i did a radiator flush and cloged my radiator if u take ur radiator cap off when its cool look at the fin's inside it u shouldint see any thing thats blocking it o my fan blade turns easy to

 

thanks elton,

I'll check the radiator and probably change the thermo since they're easy to do.

Anyone else out there with advice?

 

if u do change the Thermostat make sure u get the stock one i thought a 180 temp one would work made it worse

 

its either a bad thermostat, clogged radiator, or AIR in the system from the flush... did you burp it after changing the coolant?

my guess is more along hte lines if it wasnt overheating before, that the system wasnt properly bled after it was filled

 

jimabena,

how do I burp the cooling system besides turning the heater on to full blast? I have an old BMW that this happened to once, but it actually had a bleeder screw that released the air and fixed the problem.

so how can I get rid of the air?

-shawn

 

anybody out there? I need some help, fast.

thanks,

-shawn

 

either park on a steep incline or jack up the front of the vehicle so the radiator cap is the highest point in the cooling system. then open the cap, while its cold. this should get rid of the bubbles in the system.

 

Test the fan clutch:

http://www.barneymc.com/toy_root/techneek/fan_clch.htm

 

Check your rad and hoses for cold spots after it's reached operating temp. You can do this placing your hands in between the fan blades (ENGINE OFF!!!). There should be a gradual temp difference between the rad hoses, but there should not be any cold spots in between.