Wull

How long after driving the car should there be NO pressure when removing the radiator cap?

How long after starting the car should there BE pressure when removing the cap?

iMook

It should be totally depressurised when the car is cool - say after an hour. Once you've started it up, it should be 5 minutes or so before it starts pressurising.

I've got a horrible feeling I know why you're asking - is yours pressurised most of the time when cool?

Wull

Yep......I was out checking a few things and decided to remove the cap. Car hadn't been on since 11am so roughly 3-4hrs sitting. The coolant came out as pressure was released, the coolant was stone cold.

I then came in the house and posted this....

I then went out and decided that I'd start the car then check to see how quickly it builds pressure. Within 30 seconds I removed the cap and it came out as if it was at normal operating temperature. Stone cold again.

**** me dead

P.s this is on the track car. 02 sti running ej25, ej20 heads. Cosworth gaskets.

No overheating problems, what did happen a few weeks back, maybe a month was the blower started blowing cold air, panicked, found a slight leak at the oil cooler water pipe and checked coolant level. It needed roughly 1.7-2 litres of 50/50 mix to fill back up.

Whether that's something to do with it or not I do not know.

iMook

OK, so head gasket is the likely cause. Don't run it any more and get stripping

Wull

I’ve been advised that it could be air in the system still after the time I topped it up.

So I’ve tried my best to bleed it a little more using their method and I’ll keep an eye on it, I’ll get a sniffer test done as well. It never overheats or goes above the normal operating temp, but for the sake of £30 for the test I’ll get it done.

yabbadoo4

iTrader: (8)

flush it out totally and refill with alcazars method and see how you get on wull. bottom rad hose off then refit when empty then take off the rear pipe at the header tank which is the turbo water feed and stuff a funnel in it and fill slowly without any gurgling. takes a while but its worth it. i had the gurgling sloshing water noise from behind the dash which is common on imprezas with air in the system and this method totally cured it.

Wull

I had that noise behind the dash after topping up before, but after yesterday it’s now away.

When I replace the oil cooler water pipes the plan was to start afresh and use that technique

Wull

The oil cooler to modine water pipe arrived yesterday so today I'm going to fit that to rule out external leaks. I've also ordered the sniffer test so I can do that when it arrives.

I took the car for a drive the day before yesterday, 75 miles roughly.

Temp gauge never goes above its normal operating position, just below half. After 15-17 miles I felt like the blower wasn't as hot as it should be, in the middle position (25).....but if I turned it to 30 it would immediately blow hotter.

On the way back towards home after I had fueled up I decided that when it was blowing cold or very luke warm I'd stop and check the hoses going in and out of the heater matrix. They were both hot.

Overflow bottle working as it should, coolant level going up and then dropping back down once cooled.

Yesterday morning I removed the radiator cap after sitting overnight and there was no pressure, but the coolant level in the header tank had dropped down to nearly empty, maybe 1cm at the most.

So the plan is to replace the hose that's leaking to take that out the equation, if coolant level still disappears after replacing that then I'm 100% positive it'll be internal.

I'll also do a compression test.

Wull

I've now replaced the hose and performed the sniffer test and I'm now 100% certain the engine is FINE and the head gaskets are in tip top condition.

I can now get cracking with getting the car ready for next season.

yabbadoo4

iTrader: (8)

great result wull, bit of good news for the new year enjoy.