2004 Pontiac Grand Prix running hot with no heat?

BOILER

MEMBER
2004 PONTIAC GRAND PRIX

Engine Cooling problem
2004 Pontiac Grand Prix 6 cyl Front Wheel Drive Automatic

My heat quit working. The blower runs it just does not get hot. Now the car is starting to overheat. I changed out the thermostat. The top radiator hose gets hot but the bottom does not. Also only one heater hose gets hot. I thought I could have a blocked heater core, but would this cause the car to not cool properly? Could I have a bad water pump? Thanks

4 Replies

BLUELIGHTNIN6

MECHANIC
16,542 POSTS

First is the coolant level at proper Full mark? One radiator hose should be cool while other is warm, that means the radiator is working properly. Both heater core hoses should be warm though, if not it is most likely the culprit

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Sunday, October 11th, 2009 AT 8:54 PM

RASMATAZ

MECHANIC
75,992 POSTS

Testing the water pump:

One way to test for a bad water pump is to squeeze the upper radiator hose when the engine is hot and idling. Careful, because the hose will be HOT! If you do not feel much coolant circulating through the hose when you rev the engine, the pump may be bad.

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Sunday, October 11th, 2009 AT 8:57 PM

BOILER

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2 POSTS

I have run in to blocked heater cores before. But when I say the bottom radiator hose is cold, I mean ice cold. The coolant level is fine. Im just not understanding why the car is getting hott(in the red). Im stumped. Could the water pump be the culpret?

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Sunday, October 11th, 2009 AT 8:59 PM

BLUELIGHTNIN6