Only happend twice now but caused a bit more concern this time.
When the car has been driven hard (STI3 5dr, Unichip, Apex exhaust, baily dump valve, SS downpipe) the car quite literally spews out coolant from the expansion chamber overflow pipe.
Last time it happend (at the weekend) it took 1.5 litres back in, seems to be running fine.
Any ideas?
Cheers
Michael

Could be poor quality oil or not enough oil causing the engine to get hotter so the coolant is working harder????

Or maybe wrong dilution of coolant/water?

at the worst a head gasket problem

Michael,

When the overflow bottle "literally spews" coolant out, it can only mean one thing-blown headgaskets (sorry for the bad news). On a healthy engine in the case the overflow bottle is overfilled, worse case is it would only overflow not spew.

If someone suggests that you check your coolant tank for air bubbles when you start the engine in the morning, don't bother as even a brand new WRX has a bubbling tank so that's not a sure way of telling (it may work on other cars but not on the scoob). However, you can try this to see if you are seeing milky bubbles, this usually indicates engine oil in the coolant, vice versa coolant getting into the cylinders.

STi's have metal head gaskets but it is not infallible–ironically, my frien's STi 3 suffered massive overheating problem, he had had to top up 1.5L of water every morning and he continue to do this until one day the engine just seized. Check to see if your temp gauge is "misbehaving" intermittently.
What happened to my friend's STi wasnt a pretty picture. His block was severely damaged he had to buy a new one plus new pistons too. Get yours checked before it's too late.

Thanks - I'm getting Scoobysport to do a check on the cylinders etc - worth it to avoid any further complications.
Thanks for you help.
Michael

yosser

i very much doubt if it is head gasket probs that it will show up in a compression check it never does. even when you take it apart you will not see anything but a head skim and new gaskets cures the problems