dan2926

iTrader: (4)

Hi guys,

Just a small problem with my impreza.

Last night after driving the car it spewed coolant out of the left hand wing (bottle inside wing)

This morning i drained the whole system and filled back up with nice fresh coolant.

After about 10 mins driving i stopped and it was coming out the bottle again.

I removed the thermostat and tested it and found it to be sticking a little bit, so ran the car without it.

The car does not overheat either....

Now.....
The engine is running and i have tested for presence of gas using testing fluid and there was nothing. (Fluid stayed the same colour )
If i open the bottle lid at the right hand side of the engine while the engine is running there is bubbles and excess water coming up from it??

However my mate has an Apexi cap on his expansion tank and i tried it on mine. After trying it on, there was nothing at all coming back to rh side bottle. no bubbling up and no further water loss.

Would this be just that the new cap can take a bit more pressure or that the old cap has worn and now has a weaker spring in it??

Anyone encountered similar problem?

Oh and car is a 1997 sti type r.

Cheers Danny

saiklon

If changing the header tank cap fixed it then it was the old cap that was the problem.
The leaking combustion pressure from a blown HG will overpower any radiator cap. The pressurized radiator pipes especially when not fully up to temp are also a sign of a blown HG.

I think your HG is fine.

dj219957

a few, bubbles in the expansion tank is normal. chucking the water out of the fromt what you have said it sounds like bad rad cap. worth flushing the rad and pipework to be sure.

Antony@indigo-gt

iTrader: (2)

The water would go quite sooty if it was HG so if you have not noticed it I would say it was the rad cap.

dan2926

iTrader: (4)

Ok thanks Guys

I have ordered an uprated rad cap and a new thermostat.

Will see how she goes after i have fitted them.

Out of interest how does the system react if the water pump had failed??

Oh and also found this: http://local.import-car.com/Subaru_C...d_Wing_MN.html

saiklon

I have seen two modes of water pump failures:
1. Loud scraping noise from water pump
2. Leaking water pump.

I have heard that with water pumps which have platstic impellers these can break off and reduce coolant flow but I don't think Subarus have plastic water pump impellers.

dan2926

iTrader: (4)

Guys,

I replaced the radiator cap with an uprated one (1.3Bar)and fitted the new thermostat.
I have done around 100 sensible miles since fitting. Today i used the turbo a bit more and found a small amount had leaked out from expansion tank again.

So....The car is only doing this under boost

Any other ideas, as i dont want to start stripping the engine unless i know its definately the head gasket. It really doesnt seem to be given the testing done and the fact the car does not overheat at all, No oil in water, No water in oil, no exhaust gases present in coolant.

Could this be the symptoms of blocked radiator cores??

Im stuck

dbay

iTrader: (21)

i doubt it would be a blocked rad as it would overheat. as you have done a block test and that has come back clean i would do a compression test and see what that comes back with, maybe first stages of head gasket failure as it only does it on boost

dan2926

iTrader: (4)

Yeah i didnt mention that i checked over my radiator and its not in the greatest condition (A lot of the fins are bent, some quite deeply but no leaks from it) so my theory was the engine needs more cooling on boost, and if the radiator isnt fully efficient it will struggle to cool on boost. After seeing it i will buy a new one anyway.
I will do a compression test on her next week when i get chance, I have new spark plugs ready to go in aswell. Is the ideal pressure difference between cylinders around 7 psi??

Cheers

dbay

iTrader: (21)

couldnt tell you that mate, all depends on the age of the enigne and miles it has on it or if its standard or not, if there is a noticeable difference between bores then it will have to be investigated

Cannon Fodder

iTrader: (100)

I had exactly the same symptoms on my Impreza only worse. If I gave the car the beans then the coolant would all be dumped into the overflow resevoir.

When not using boost it was fine but any use of turbo boost would cause exhaust gases to leak into the coolant; my problem turned out to be that head bolt stretch/head gasket failure. I tried new caps as you have done but it didn't cure anything.

Carrying out a sniffer test didn't do any good as you can only create boost when you are in motion. If it is gasket/bolt failure then get your engine block decks checked and skimmed for warping as well as your cylinder heads.

I ended up having a complete forged engine build in the end, I hope this sort of helps.

dan2926

iTrader: (4)

Ok cheers for that guys, will see what i find.

The annoying thing is the engine was rebuilt around 3000 miles ago due to failing oil pump, HG etc etc were all done then. Car has only done 87,000km all together. Well if its serious i will either need to upgrade the engine or break car for parts depends what the wife says.

Cheers

bigpimp347

i know what your feeling i have the same problems....
over heated once, randomly, new pump fitted and cam belt, problem sorted for three weeks, then one day top hose blew..
now with header cap OFF runs, ticks over, does NOT over heat all seems fine..
rev and water goes from the header, let off the revs water comes back, over flows and has some white froth, not oily, just bubbles..water/coolant is still clean..

put on rad cap run, pressurises up, doe snot over heat, leave it over night and top hose is flat, like it's sucked all the air out the systems..
no loss of oil, water seems to smell ok, not tested it for gasses yet..
i'm hoping blocked core as the new pump, and limescale could have blocked the rad cores a bit..

but the high pressure and the froth is a concern,
also engine believed rebuilt only a year or so before i bought it, only in UK 6 years, spent more time off the road than on,

i'm waiting the doctors report...cars not been drove for three months, what a waste, i've lost my heart for it..!!

dan2926

iTrader: (4)

Yeah mate it sucks dont it
I fitted a glass sample jar to my overflow to see how much coolant im losing, i drove 70 miles today not using turbo and checked the jar when i got home........Nothing in it at all.
Going to use the turbo a bit tomorrow and see how much im losing.
From the above i cant help thinking....After rebuilding the engine i wonder if they torqued up the head bolts after running it in. It was a repuatble garage who did the work so surely they would have........

If HG is gone i Priced up the parts i would need

Exedy Clutch and flywheel.
Radiator.
Cosworth Timing Belt Kit.
ARP head bolts.
Steel head gasket kit.
Water pump.
Plugs and a few other bits.

I would be looking at around £1600 and 1k labour.
Probably worth more in parts but i do love her ?......

dan2926

iTrader: (4)

Oh well thats the scoob finally decided whats wrong with her. Head gasket is fuc*ed . Took it out today and it started to spew white smoke. Got it home and switched her straight off, still no overheating tho and coolant system still plenty in it.
I just went to start it to put it up the drive and it wont start, i got a small clunk from what felt like the clutch area any ideas why. as i said it didnt overheat??

bigpimp347

the white smoke you'd say water and oil, saying that mine does nothing, no smoke, no oil in the rad water, just pressurerises up, yet trying to find someone who wants to do thwe job is becoming a joke in it's self..!!

i have money sat here waiting for a job to be took on...whats wrong with people we all loaded and don't need to work or want money

dan2926

iTrader: (4)

Yeah its a joke buddy. Not too bad up here to get someone although i will probably be doing most of it myself. Just pricing everything up and think the wife is gonna kill me