Heat goes UP then down then up

[chevyy1212]

Ok 07 GT it's my mommys... The heat takes forever to get up to temp then fluctuates from operating temp down to 140-150ish so the heat never stays at a good temp. I've changed the Tstat and the only thing I can think of is air left in the system? Any special way to bleed these I thought there was been years since I had my GS.

 

[Fivefingerdeathpunch]

I'd backflush the heater core while your at it too.

Then remove the thermostat, refill the LIM with coolant to get the level all the way up, re-install and top off the radiator. Run the car with the rad cap off and allow it to warm up, add coolant as needed. You shouldnt have to bleed through the T-stat housing doing it this way.

 

[chevyy1212]

I'd backflush the heater core while your at it too.

Then remove the thermostat, refill the LIM with coolant to get the level all the way up, re-install and top off the radiator. Run the car with the rad cap off and allow it to warm up, add coolant as needed. You shouldnt have to bleed through the T-stat housing doing it this way.

I like this plan. Is it just me but I remember these cars being a pain to get the air out of the system?

 

[Fivefingerdeathpunch]

I just think some people have bad luck???

I've never ran into a issue with one yet, worked on dozens of 3800's and never had a issue yet. Sure some take longer but knowing a few tricks of the trade help. Squeezing hoses, revving the motor, quick shuts offs to burp it and so on.

 

[Scottydoggs]

ive yet to have air bound core but it sure does seem to happen to a lot of cars here.

 

[chevyy1212]

ive yet to have air bound core but it sure does seem to happen to a lot of cars here.

Yea she got screwed out of 3 flushes at a shop a few years back after I took it flushed the heater core and bleed it off a few times been good for years now it's doing it again after the resivour hose got ate up buy the belt. Very few things can cause this tho. I jacked up the front end for kicks while bleeding too.

 

[Scottydoggs]

bleeding the t stat wont fix air in the heater core. the core needs to be filled up. take both hoses off the alt bracket, and flush one with a garden hose, then flush the other one, then put the hoses back on with them as full of water as possible.

 

[chevyy1212]

ive yet to have air bound core but it sure does seem to happen to a lot of cars here.

Yea she got screwed out of 3 flushes at a shop a few years back after I took it flushed the heater core and bleed it off a few times been good for years now it's doing it again after the resivour hose got ate up buy the belt. Very few things can cause this tho. I jacked up the front end for kicks while bleeding too.