Air Bubbles In Coolant

[300owner02]

I have a 2002 IS300 bought new with around 130k on it and take excellent care of it other than the milage beating. This is the second time in 1-2 years that I have had the water gurgling noise that sounds like it flows right down under shifter. I always hear it as I accelerate from stopping point. Having it fixed prior, I now know what is wrong having looked back through my receipts from the dealer. It was recorded as air bubbles in coolant.

What I want to know is why does it seem like it's happening more often than it should? What causes this to happen? Driving habits? Defective? Is it something I can fix myself?

Please shed some light cause its rather annoying that I keep having to take it in to get fixed as if it was a yearly routine maintenance.

[smooth1]

The coolant system is a pressure sealed system. You may just have a bad radiator cap that is sticking open and allowing air or failing fully pressurize the cooling system, which is what keeps the coolant from boiling.

[bartkat]

ounds like air in the cooling system that has been trapped in the heating core. If it is this, I had this when I changed my coolant at 30K. The air needs to be bled and there is no bleeder screw on the IS. I bled it by taking radiator cap off, switching the heater on to full blast, then turning engine on until the thermostat kicked in and cycled coolant through the whole system. Unless the heater is on it will not cycle through the core. Left engine on for a few minutes until the fan kicked on and shut engine off. Topped off with some more coolant to replace the escaped air.....No more gurgling.

http://my.is/forums/f115/gurgling-noise-be...h-vents-249911/

[aycy]

how to know if there is air bubble in the coolant??

[smooth1]

You can hear it. It sounds like the engine is grumbling.