Keef69

My classic STI has had an over-heating problem, the temperature goes right up, but when I hit 5,000 rpm, it drops back to normal and stays there a while even at low revs, plus my heater blows cold air under 3,000 rpm whether the temperature gauge is high or not. Yesterday it over-heated badly and anti-freeze/water poured all over the place. When I tried to accelerate, and once the turbo came in, it backfired constantly. Had it towed to my garage.

Is this, as I suspect, a head gasket problem and if so, will that sort the heater out too?

funkyspider

You might be lucky and it may just be a cracked radiator or a hose clip
where was the water comming from. I recently had a scare and as all the horror stories about overheating scream head gasket and are followed by pound signs I feared the same, stressed about it for a few days and was charged 45quid to fix the knackered bottom hose clip and to give it an oilchange

is there any sign of oil contamination in the water, this will probably be visible in the water on the white overflow tank connected to the rad.

is there any sign of water contamination in the oil (will look like milky mayo type residue on the dipstick)

at tickover you may be able to see air bubbles in the water, again in the white overflow tank.

The heater will blow cold if you get an airlock after you filled it up again, or the water level is low by the way

I cant imagine what you are doing at 5000rpm on an overheating engine and as for accelerating hard enough for the turbo to come in after loosing all your water - if your head gaskets havent gone yet then they soon will, poor car !

Let us know the worst, ur symptoms and the result may help someone else.