1998 Chevy S-10 Chevy S-10 running sluggish after water pump

KINGJC4ME

MEMBER
1998 CHEVROLET S-10
4 CYL
2WD
MANUAL
98,000 MILES

I recently discovered that the water pump in my S10 was leaking from the weephole. I originally discovered the problem while investigating why my heater wasn't working. I replaced the pump with a new one, and I changed out the thermostat (making sure to orient it correctly). I completely back-flushed the cooling system (per Prestone kit/directions). On starting the truck, it runs OK for awhile, but as it heats up it becomes sluggish, and eventually conks out. The heater still shoots out cold air. Also, even though I don't see any leakage, the amount of liquid in the radiator is going down. After running the engine for awhile, it doesn't seem to be overheating, but there is a lot of gurgling coming from the heater core. Have I blown a head gasket, or something?

2 Replies

PEAR69

MECHANIC
1,482 POSTS

As the engine heats up does the thermostat open? To see just feel the upper radiator hose when the engine is heating up--it should go from cold to hot as the engine gets hotter.
Check your engine oil and transmission fluid for engine coolant. (Just to be safe). The coolant is going somewhere or it just may be low.
To test for a blown head gasket do a pressure test either on each cylinder or pressureize the radiator. Check for air leakes or air bubbles in the radiator.
Does the engine smoke or anything like that as it heats up? Pull the spark plugs let me know what they look like.