Air lock Gen IV

[stumpeater]

Hi Guys, I've put over 1000k's on the car now, all going well, and lots of fun. Whilst out and about a few days ago I had the need to reverse up a very steep drive, and the donk gave the impression it was boiling, the temp was OK so I popped the bonnet to see the header tank, which is mounted high on the firewall, had spat coolant out of the overflow pipe, it seems the extreme angle of the engine had freed up an air bubble somewhere in the motor.
The donk is as it came out of the box and plumbed the same as my commodore,and the small vent pipe on the front of the heads is hooked up to the tank. I was just wondering if any one else has had the need to "bleed the donk" at all? It has not done it since and has never overheated.

[gjkrv8]

Hi Peter,

Giving you were going up in reverse I would have thought the opposite. Anyway, just a quick dumb question - Do you run an overflow tank such that you have a closed system so no air can get in? You mentioned your header tank spat out coolant - was that into your overflow tank?? I would have thought an air bubble would cause it to spit bubbles/air etc.

I found initially with my LS1 my initial overflow tank (a skinny shiny aluminuium one) was too small and it would overflow and then suck air and eventually after a few cycles there would be air in the radiator/engine block and my engine would run hot. My header tank was always going empty.

A cheap $20 plastic overflow bottle did the job and it pretty well doesnt use water now.
I have been stuck in Hoddle Street on a 36 degree day in peak hour and it all works fine now.

Hope you find the problem.

rgds

Gregg

[Towmaster]

Won't have that problem with a windsor.......

he he

[stumpeater]

Hi Gregg, it spat out air and coolant just once, it is a sealed pressurised system, no over flow. It has not used coolant at any other time, in fact the level dropped only slightly in the tank. I leave a air pocket in the top. The fact that no one else has had the problem suggests it's not a common problem. so maybe just a one off. Thanks.

[Tenrocca]

I crack the oval plugs either end of the engine when filing up - once coolant starts to come out close em up. No cooling issues except forget to tighten radiator cap.......