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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 29428
Experience:  GM Grand Master Technician 2007. 14 years experience.
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2001 chevy truck: has no heat, Flushed heater core..hose..water pump

Resolved Question:

2001 chevy truck 5.3L has no heat, Flushed heater core and replaced thermostat then heat worked for one day. lower hose cold to touch so replaced thermostat again and still not warming up. Could it be bad water pump
Submitted: 5 years ago.
Category: Chevy
Expert:  GM Tech (Cam) replied 5 years ago.

GM Tech (Cam) :

Hello, I'm Cam. Please include all the details about your issue so I can accurately advise you. I cannot see your vehicle so please be detailed.

GM Tech (Cam) :

No, if the pump was bad it would overheat. Can you try flushing the heater core.

GM Tech (Cam) :

Take the lines off the heater core and flush with a pressure washer. Push into the cold line first. Something is blocking the coolant flow through the heater core.

Customer:

Already have

Customer:

The lower hose on the engine is cold will not get bwarm

GM Tech (Cam) :

Lower rad hose then not heater core hose is what you meant?

Customer:

yes

GM Tech (Cam) :

OK, sorry,

GM Tech (Cam) :

YEs if the heat worked after for a day then I would look to see if something got caught in the thermostat and made it stick open.

Customer:

Temp gauge read about 190 deg but remove lower rad hose and coolant is cold

Customer:

I replaced the thermostat twice

GM Tech (Cam) :

Ok, no air lock in the heater core then?

Customer:

No

GM Tech (Cam) :

how cold is it outside?

Customer:

50 deg

GM Tech (Cam) :

IF you put a sheet over the front and rev the engine to 1500 in the shop, does the tempo rise?

Customer:

I had card board in frt and reved in gear and temp went up to about 210 but lower hose still cold seems that the thermostat not opening for what ever reason. when the heat did work the lower hose was hot.

GM Tech (Cam) :

What does not make sense is the heater so does it get full pressure when this happens?

GM Tech (Cam) :

IF no then I would agree the water pump is the next liekly place.

GM Tech (Cam) :

If it does then possibly head gaskets.

Customer:

when i removed the thermostat and see no restiction

GM Tech (Cam) :

ok

Customer:

when the themostat is not open then the heater core wont get hot

GM Tech (Cam) :

but that does not make sense since the flow should push hot water into the heater core.

GM Tech (Cam) :

So head gasket is looking likely.

Customer:

Would i smell coolant or see in the oil

Customer:

no sign of head gasket leak

Customer:

Ill pressure test system and thank you for your advice.

GM Tech (Cam) :

Not every time no. There are different types of head gasket failures.

GM Tech (Cam) :

Sometimes all it does it push combustion into the coolant and the pressure stops the flow.

Customer:

ok il look into that

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