My 97 Tahoe (5.7) started to overheat. Upon inspection the 3/4" heater core hose at the firewall had a loose clamp and was the source of the leak. I tightened it up, it stopped the leak and off I went (mistake #1).
Truck was running hot but I thought it was due to being low on coolant from the leak. Topped it off and it's still no good. Truck is going through wild temp swings from 190 all the way up to 280 (max on the gauge) in a matter of seconds. Bringing up the RPMs seems to bring the temp back down but only for maybe a minute then it starts to climb again...rinse and repeat.
The radiator, thermostat, upper hose, lower hose, and both heater core hoses are only a few months old so I do not think they are the problem although anything is possible.
I *think* I have a blocked heater core, which brings me to my question. In this truck with the temperature selected to cold on the dash does water flow through the heater core or does it only pass through it with the dial turned to warm? If it only goes through when you have the dial on warm then I don't think the heater can be my problem because it overeats either way.
The water pump is dry and quiet...don't think that's it either.
I love my truck but this is PITA!!!
Truck was running hot but I thought it was due to being low on coolant from the leak. Topped it off and it's still no good. Truck is going through wild temp swings from 190 all the way up to 280 (max on the gauge) in a matter of seconds. Bringing up the RPMs seems to bring the temp back down but only for maybe a minute then it starts to climb again...rinse and repeat.
The radiator, thermostat, upper hose, lower hose, and both heater core hoses are only a few months old so I do not think they are the problem although anything is possible.
I *think* I have a blocked heater core, which brings me to my question. In this truck with the temperature selected to cold on the dash does water flow through the heater core or does it only pass through it with the dial turned to warm? If it only goes through when you have the dial on warm then I don't think the heater can be my problem because it overeats either way.
The water pump is dry and quiet...don't think that's it either.
I love my truck but this is PITA!!!
