boiling noise

[poncho 1]

hey, when i turn off my car it will make a boiling sound for a couple of sec's (35) ish whay is my coolent boiling ? .. the last time i heard that sound was on may '94 sunbird (3.4) right before the heater core went . is the heater cor about to go on my GA ?? OR IS THERE air in my system ? please help i'm trying to do all i can to help the poor cooling system on my 3.4 THANKS !

[gt00]

Check the coolant level and then bleed any trapped air from the cooling system using the bleeder screw . The rad cap is good ? and you're using the correct 50/50 coolant mix right .. :???:

[poncho 1]

the dex cool is new as is the rad cap the guythat did the lim bled the system
i'll try again on the weekend i heard from a guy that i should put the front of the car up on jack stand s to put the bleeder valve at the highest point of the system .. any truth ??

[Blackhawk]

It's already at the highest point. You can bleed it in a minute, just open the bleeder valve while running, making sure you don't get sprayed, and leave it open til only liquid comes through. Then check your coolant level and you're good.

[rixGAphx]

Despite the new rad cap, I think your system isn't holding pressure.
The plastic sidetanks on the heater core (of both the Sunbird and GA) develop hairline cracks, which eventually leak under pressure and can afil completely.

When you shut the engine off, the coolant stops flowing.
Latent heat at the cylinder walls, and especially at the exhaust valves of the heads, must go somewhere, and it heats the stagnant coolant in the adjacent water passages.
*Some* of this water gets very hot, much hotter than t-stat setting; more like it reaches 230+ *F!!
Water boils at 212, water+AF boils at about 220; pressure in the system increases the boiling point by about 2*F per 1 psi of pressure.
So a system with 14 psi gets 28* of 'boil-over protection from the pressure factor, on top of the protection of the AF.
Therefore, a GA *shouldn't* boilover until 248*F

Your engine is getting localized 'boiling' as it sets and cools-off, and the pressure forces gurgling liquid through both the rad hoses and the heater hoses.

Go back to the mechanic who just took all your money but didn't yet completely fix your cooling system.
Inform him of the condition, and ask for a coolant system pressure test, WHILE HOT (since the plastic heater tank hairline cracks might not leak when the liquid is cold).

Another possibility is the neck of the reservoir itself: If it is nicked, or mis-shapened, then even a new cap might not seal tightly.
And if a new cap is overtightened, it can distort or damage the delicate rubber sealing gasket enough to prevent sealing.
Only tighten as much as an average woman can easily do one-handed; that is enough to maintain the 14 psi seal.

Hope this helps,
-Rick