2004 H2 overheats.

[rkhal]

I have a 2004 H2 and I am getting overheating indications on the driver corntrol center and the heat gauge. It was fine when I drove it home and the next morning at 2am when I started for work it overheated with 5 miles of home. I have changed the thermostat, the water pump, the fan clutch and the coolant cap and it still overheats. I am desparate. Any ideas?

[tomp]

Might check color of fluid to ensure it's not getting mixed with tranny fluid!

[porschett]

Blown head gasket?

[IRA51]

Is it useing coolant ? if it is you need to find the leak . if not it may be a cloged radiator and you may need to have it rodded out or replaced . as said B4 if you mix Dexcool with the green antifreez it will clog the system. if it's a bad head gasket it wiil show up at the tail pipe as a mist or worse. you can also pull the spark plugs and see if they look right ,if one is a differant color you can bet that you have a leak in that chamber and it is ether a cracked head or bad head gasket . head gaskets go bad on these engins because people never change the coolant and beleive GM that Dexcool is good for 100000 miles ,in fact you need to flush and change it with a thermostat every 50000 miles or 3 years which ever comes first .

[rkhal]

No coolant usage --- 60,000 miles. No none gm antifreeze -- confusing thing is it didn't gradually start getting hot --- just all of a sudden --

don't think head gasket as no water in oil or mist in tail pipe --- haven't pulled plugs yet

[IRA51]

try undoing the radiator hose's from the radiator and get a garden hose and a rag use the rag as a seal and stick the hose in the bottom of the radiator and turn the water on full blast with the upper hose off the radiator ,you will need to hold it in. see if you get the water to come out the upper inlet of the radiator with the same force as the water going in. if not you have a cloged radiator .

[pteam]

Do you have the fan shround on? You must have it on or it will periodically overheat, one of my h2s did from the previous owner taking the fan shroud off.

[rkhal]

Originally Posted by rkhal

I have a 2004 H2 and I am getting overheating indications on the driver corntrol center and the heat gauge. It was fine when I drove it home and the next morning at 2am when I started for work it overheated with 5 miles of home. I have changed the thermostat, the water pump, the fan clutch and the coolant cap and it still overheats. I am desparate. Any ideas?

Okay, you aren't going to believe this. I changed the thermostat, the radiator cap, the water pump, the fan clutch and the sensor and it still overheated. I refused to believe that it could be the radiator because it came on so suddenly. No gradually becoming less efficient at cooling, just wham. I didn't believe it could be the head gasket because I had no water in the oil or in the transmission and no steam coming out of the tail pipe. So before I got serious about the heads I pulled the radiator and had it rodded out. The main part of the radiator was fine but the nipple for the small hose going to the overflow tank was plugged. (it only has a small orfice deep within.) When that was unplugged the problem went away. I drove it for over 2 hours today in 100 degree plus temperatures with the ac on and a lot of idling. Temperature was rock solid.

[Intercooled]

Thanks for sharing..good find!! I'll Keep that info in the memory banks!