Coolant Problems

[sjonz3]

Hi, I recently purchased a 93 suburban 4x4 with tow package that has 90k miles on it. This past weekend I took it up to the mountains to go skiing. Every time I went up a mountain pass the temp. gauge went through the roof. A couple of times I could here the coolant boiling in the over flow resevoir. As soon as I backed off the gas and nursed it along the temp dropped right back down. At times it would even drop down to 120 degrees.?.? I am not really sure where to begin with this problem, if anybody has any suggestions I would greatly appreciate your input.

thanks in advance
sean

[brooster]

Is the radiator full of coolant? Is the fan belt tight and in good shape? Does the fan turn fast enough?
Is there trash, leaves, etc between the radiator and A/C condensor? How does the engine run? Any misfire, water (other than normal condensation) coming out of the tailpipe? Is there a thermostat in the engine and is it working properly?

Answer these for starters.

[Regency Burb]

Sounds like a head gasket.

[trannyman52]

another thing to look at //// rad core possibly plugged

[sjonz3]

thanks for the replies. i have checked all the fluid levels and replaced the thermostat. i was driving around town today and the temp. shot through the roof. no hills or anything just pancake flat driving. do you think flushing the system might work?

[CHOPTOP]

i am having the same problem with my 88. i have tried every thing with the best results coming from replacing the fan cluch, though i am now suspecting a blow head gasket

[sjonz3]

i actually had blown a head gasket, and then later found out that i had cracked the head. that one hurt the wallet.

[wagoh]

I am having the same problem with my 93 suburban. It overheats quickly when ac runs but overheats also when ac is off, just takes a little longer. I have taken out the termostat and replaced water pump with no luck. How do I check to see of the radiator core is plugged? I dont see any debris on the front of the radiator. I have had a problem with my front heater core breaking (4 times since Jan) so could a new radiator solve my problem? Thanks!