Thread: Air bubbles in overflow tank

Hey guys. I recently installed my 90x86mm sleeved motor and noticed something strange. After I drive around for a while and I switch the motor off, a few air bubbles will pop up inside the radiator overflow tank. No bubbling as such, just a few single random bubbles that pop up about 3 seconds apart, and for about 3-5 mins after I switch off, after which it then stops.

Water temps while I drive are between 75deg C and 90deg C.


Funny thing is if I just idle the car to the point that the fans come on and I switch off, there are no bubbles. Only after I drive it around for a while. Also, I'm busy breaking in this motor so I'm only revving up to around 4500 rpm.

I'm re-using the Mazworx gasket. It was n my motor before but it only started up and never drove with it.

Were could the bubbles be coming from? I've bled the system best I could.

was the head n block resurfaced?.... im hoping its that u didnt resurface the head or the gasket not sealing properly.... dont even wanna say worse case senario.....

Block yes, head I'm not sure. Someone else built it for me.

do you have new Rad Cap?

Head gasket, most likely..... search VVL coolant boiling over or look for on it on the front page in this forum.. theres a video

If the system is bled and there are bubbles with just driving around, I am sure it will get worse when you start to bring her to 8k-9k. It could be head and block not sealing properly. Uneven head and/or block or bad hg. Or detonation.
'
Peace

http://www.sr20-forum.com/vvl/65159-vvl-coolant-boiling-over.html

Check the video of the coolant overflow bottle shaking like a junkie. Is yours doing it that bad as well?