98 s10 2.2 coolant system

[electrasport]

After replaceing water pump and therm, coolant seems to flowing back into the reservoir tank? Whats wrong?

[OverBoardProject]

How's your rad cap. The stock Chevy are junk, and should be changed to a scant
There is also a small chance that they got you the wrong water pump.

A waterpump designed for a v-belt is designed to run 1 way, where a waterpump designed for a serpentine system is designed to run the other direction.

[electrasport]

After calling a radiator specialist, he said a blown head gasket could do the same, and he could do a chemical test for 20.00 to see if there was any gas,oil or coolant mix. To my eye there is no coolant or water in my oil. But will soon have a pressure test done on a lift to find the problem.

[OverBoardProject]

Sorry I never thought about that, and being a 2.2L there is a good posibility of a fried head gasket.
They don't always mix oil with water, it really depends upon where they blow out.

If it didn't give you any probelms before the recent work there's a good chance that it isn't the head gasket.

$20.00 to check that is kind of outragous. It's about a 1 minute test using a rad pressure tester.
Another way is if your reservoir puffs out like a ballon the moment that you start the truck.
If it does your head gasket is toast

[whitetrash982]

actually OBP , i think the test that his guy is refering to , is a carbon monoxide test of the coolant , theres a special fluid you put in a special pump , hold it over a hot rad\resivoir and pump it , and it sucks the fumes from the coolant into the pump , and the fluid will change color if it detects carbon monoxide , but will stay the same color if it doesnt , but if it does , you got a combustion leak on one of the cylinders somewhere , but still , not really worth 20$ , you would proaly pick one up at your local parts dealer , ask them for a combustion leak checker