Overheating

[turbo boy]

I thought i had an airlock but im constantly re-filling it with water as it keeps overheating. I have flushed out the coolant system and although it works for about15 miles or so the coolant light comes on again. After a run when the engine is turned off it sounds like the kettle is boiling. Whats wrong with it?

[BlitzBoy]

when it overheats does spew water out from the overflow tank?
any signs of a water leak?
Have you done the champagne test, to see if your water seals are fubared?
To get rid of airlocks, I run the car from cold without the filler cap off, and when it gets up to temp and the thermo stat opens, water should start coming out of the filler neck quickly switch off car, top up water then put cap back , switch back on and it should be ok if its just an airlock.

[turbo boy]

Could an airlock cause overheating tho? When there is enough water yes it tries to escape from the overfill tank.

[turbo boy]

How do you do the champagne test?

[BlitzBoy]

yes an airlock can cause overheating, thread to champagne test
http://www.mazdarotaryclub.com/forums/showthread.php?t=65227&highlight=champagne+test

[turbo boy]

Will check this out later, thank you for your help mate.