GURGLING AND BUBBLING IN COOLANT OVERFLOW TANK

Mar 31, 2006 4 Replies

I have a '91 Maxima. The temperature gauge indicates a normal operating temperature while the car is running.



The car was idling for 3-5 minutes after being driven 15-20 miles. When I shut off the engine, the coolant overflow tank filled up completely, and coolant began gurgling and bubbling, coming out of the pressure valve on the side of the overflow tank.



Another time, the coolant began gurgling and bubbling, but the overflow tank did not fill up, and did not overflow.



Has anyone experienced this situation? Can you offer advice as to what is causing this, and what needs to be repaired? Any links on the Internet that you can point me to, so I can better understand the problem?



Thanks in advance for your help.


You have air in the system, coolant boils, air has to be bled out. FSM suggests rising car and opening the bleed valve. Read the links for details:

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The bleed valve is on top of intake, near [7.], open when engine cold. If its still boilin after bleeding, open heaterhose slightly ajar at [14.] so that it drips (bleeds), but cannot slip off, then drive one hour adding coolant if/as necessary.

after the car has completely cooled off, remove the radiator cap and check the cooling system. Chances are it is low on coolant, the next thing to do is look for a leak.

This is a warning sign that you've got potentially big problems. Address them right now. With that age, you could be leaking coolant elsewhere. It could be a faulty radiator cap. Every time it overflows, you need to replace what you've lost. Check for air in the system. Or just take it to a reliable shop if you're not mechanically inclined. There may be more than involved with it, but NOW is the time to fix it. Wait any longer and you're looking for a new engine!

...This is a warning sign that you've got potentially big problems. Address them right now. ... True.

Typically Boiling, Air doesnt appear w/o Leak, hot spots from air pockets =bad cooling, may destroy engine. However, IF coolant change (periodic maintenance) was not done properly with air bleed, no Leak is 'needed.'

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