2003 Monte Carlo 3400
I have searched & not found a solution yet. Sorry if my search fu is weak & I missed it.
Car started running hot about a month ago. It has red-lined 3 times. I have flushed & backflushed the system. I replaced the thermostat & water pump. No fix yet. the heat isn't working. With the coolant full I remove the hose to the heater & no fluid is flowing unless I rev the engine. Sometimes while driving if I rev the engine the heat will momentarily work.
Any help would be greatly appreciated.
Heath

 

any luck with this yet ?

 

If its not loseing or using up coolant.....

It probably has ended up with an air pocket in the system...
You need to get the car up to running temp, shut it off... On the top of the thermostat housing is a way to drain the air out of the system.(Bleeder screw)... you may have to do this several times before you get it all out....

The air pocket actually causes a problem with not letting the coolant flow freely... the air pocket is like a dam.. you need to remove it.

Be sure to open that bleeder slowly.. and cautiously... eventually you should just get a stream of just coolant once the air had been bled out.

This only works...provided you don't have any leaks in the cooling system.

 

I would first check your oil (look at it on the dipstick, is the level correct or too high, next, check the oil cap for a milky substance). This is to see if you have coolant getting into the oil. If so, it's probably the LIM gaskets.

Next, follow David's steps of bleeding air out of the system. Lots of air makes it tough for coolant flow.

It's also possible there is a "blockage" somewhere in the cooling system or a leak elsewhere. To leak check, do a loan-a-tool on a radiator pressure tester (allows you to pressurize the system and then look/listen for leaks).