Chevy venture heat/overheat problem?

Question

hi, my 2003 chevy venture, in winter the heat began to stop working, and it would blow out air but cold air, then later on it would b hot then cold and keep changing, but the A/C works. and now it over heats real fast and bad. and yes the coolant and oil is good. maybe the heat thing is clogged how much does it cost to fix, and can i buy something to clean it??

Answer 1

check coolant level in the radiator itself not just the coolant tank. the intake gaskets are known failures on these cars. Change the thermostat after the repairs for coolant loss

Answer 2

it could be the vaccum lines that open and close the valves for the heat

Answer 3

It does sound like an Intake leak. This a very common problem with this motor. Take a flashlight and look under the throttle body. The throttle body is  what your gas peddle cable attaches to. The black air intake pipe is attach to your throttle body. You have to look real close but you will most likely see orange coolant there. You probably have a air lock in your engine. You have to bleed the air out to prevent this. Your repair manual will give you the steps to do this

Answer 4

Intake gasket failure is very common on these vans. It is possible you think the coolant is full, but actually has a big air block in it. Have a shop purge the air out of the system and fill it, if it is still overheating, you have a bad head gasket, which also occurs with the GM 3.4  

Answer 5

if its full of coolant then thermostat is bad in most cases

Answer 6

That sounds like a leaking head gasket or warped or cracked head. It's a very common occurrence on the 3.4 V6 engine in your van. Prepare to open up your wallet/purse...