Hi all, please bear with me on this, and, if poss, read it all and voice an opinion.

I apologise beforehand if it's SIAL, but I'm baffled, here goes:

A month ago, I joined some fellow s'netters for a spirited run from Stafford to Shrewsbury, we travelled on mostly A/B roads.

Arrived at destination, lost a large % of coolant, temp gaige read normal and heaters were okay en route. Got car to my mechanics' garage on low loader and discovered that inner seal on t/stat had split, therefore hindering operation.

Replaced t/stat, re-filled system and car's losing coolant after low mileage journeys, this was about 3/4 weeks ago. Have monitored coolant levels and have been topping up ever since. However, the car hasn't leaked for about 10 days and the following checks have been carried out to date:

1) new thermostat installed and checked
2) coolant sytem pressure checked and holding at .9 bar
3) no external leaks as a result of #1
4) liquid head gasket check done today, hot and cold temps and NO indication
of exhaust gases in coolant
5) no leaky pipes of any nature
6) oveflow bottle is not leaking
7) header tank is good
8) radiator CORE is a year old
9) water pump is operational
10) No water in oil and vice versa.


I've purchased a new gasket set and cambelt from David at APi and was prepared to have it all done today, but my mechanic that is ex-subaru and well thought of on here, insists that it is NOT head gasket. The leak is very intermittent but after a 40 mile trip, admittedly off boost, to the garage there is not a sign of water loss at all.

I'm completely stumped and very reluctant to drive the car if I've got to check coolant B4 and after each journey and becoming increasingly pissed at driving under 3k and totally off boost.

There have been a few bubbles in the o/f bottle but not for the last 10 days and I sat in the car last Friday on the phone for 20 minutes at idle, that was after a 10 mile journey in peak-time traffic followed by another 3 or 4 miles and NO LEAK.

Temp gauge is reading normal and engine doesn't feel any hotter than normal.
I've noticed puddles inside the backbox but it is a 5" firestorm that catches heavy rain pretty quickly.

PLEASE CAN SOMEONE OFFER SOME INSIGHT INTO WHAT IS REALLY STARTING TO **** ME OFF...................!!!!!!!

If it's not a head gasket problem, what is it?

Car starts first time every time and there's no loss of driveability.

I've been advised by the mechanic to collect her tonight, drive her like I normally would, ie:like you're supposed to and monitor closely for another week b4 I spend 3-400 quid on unneccasary labour.

All views appreciated.

Thanx for reading, I think I've covered everything.

Skoosh.

96uk turbo wagon, full decat, scoobyecu and HKS green panel filter.

 

Have you checked the pressure that the filler cap releases(not the header tank).There is a pressure release valve on it. If its releasing to early it will allow the coolant to escape. i.e. loss of coolant no sign of any leaks.

 

Thanx for reply TT.

That's the only thing that's not been tested mate, I'm gonna buy another one tomorrow and try it out, although I did borrow one recently aonlt yo experience the same leak.

PISSING ME RIGHT OFF NOW.

Picked her up tonight and drove her like a scooby, got to a pub.....NO LEAK.

Left the pub, drove home at 5k max revs and she's leaking, will re-check in the am.

Si.

 

Can you tell where the water is coming from - filler cap, overflow bottle, or a hose?

Using boost would cause more water loss if the head gasket had gone as more pressure to get into waterways...

 

Skoosh - How did you go on with this ?



Mark

 

Sounds like thermostat sticking Mark.

 

Are you refering to the plastic bottle? if not what.

I have got similar problems, have done liquid headgasket check no gasses in the water. No sign of any leaks and i have an alloy header tank with a new H/P Sti cap.
My problems all started after the top radiator hose burst.

Cheers

 

I think is temperature related. If it looses fluid on WOT or fast runs, then is temp related. Saw a case of that once, the only signs were bubbles on top tank. First it appeared that it was headers. But no leak! Just excess heat in motor/tubo causing it. The bubbles were water passing 100ºC and evaporating. Some duct tape around the radiator and bigger tubes did the trick. But could also be a fautly termostat, and water evaporates itself from excess heat and no circulation....

Note that it was a modded car, with FMIC (too close to the radiator as well).

Just my .2hp...

 

I have a Modded Car with a Large Apexi FMIC. But i also have a different Front Bumper with a Full Cut-out allowing air to fully enclose the FMIC. it would then pass through onto the Rad with ease.

 

I have a similar intermittant problem, which I think may be cause by overheating in some part of the cooling system but haven't yet done a headgasket check.

What exactly is a 'liquid head gasket check' ?

Andrew...

 

it is a coloured dye, if it changes colour then it confirms, exhaust gasses are getting into the coolant, either headgasket or cracked head can give these symptoms

 

Is this something you can do yourself ?

 

I believe it is, My uncle did mine as he has his own Garage, and he was down at the weekend so brought some with him.

It is commenly used by garages AA etc. and should be readily available at most motor factors.

 

Cheers.

 

No the plastic bottle is not pressurised. The main filler is on the offside top off the engine above and infront of the turbo.DONT open this when the engine is hot.

 

With respect to my original post, I collected car that night, drove her for 10 miles upto 6000rpm, yes she was warmed up. No leak at pub halfway, drove her home, another 10 miles and it bloody leaked.Liquid head gasket check done, no sign of exhaust gases in coolant.

She's leaked once this week, just gone and checked coolant now cold, no leaks and no fluid loss............AAAAAAAAARRRRRRRRGGGGGGGHHHHHHH..!

This is doing my head in now, going to check out the rad cap this week, perhaps it could be as simple as that. Also had a new t/stat fitted after initial coolant loss......temp gauge is defo working properly but car not overheating according to that.

I have, however, noticed particles in the header tank although I suspect it may remnants of radweld i added before replacing rad core.

I'm driving her normally at the moment and religiously checking coolant.

Wish I had a magic wand or crystal ball.

Si.

keep this thread going guys and someone, somewhere, somehow, will have an answer........perhaps

 

what header tank you got fitted? When i first got my Impreza i was loosing coolant and found the seal around the Std Header Tank was leaking when the car got hot. but it was only steaming out of it. i Got an alloy one and used no water for 4 months (Till Now)

 

also had to replace the header tank on mine if that helps

also had a very small leak which only leaked when the throttle was prodded, so when ever i popped the bonnet and let it tick over, i could never see anything

i was probing around and knocked the throttle cable under the bonnet, which made hot coolant squirt in my face

 

here is the Item that was used on mine.

Out of Curiosity. i put in some more radweld as it is still using water. i run it up and performed the collant test again, this time it showerd a problem. not sure if the radweld was causing a Reaction.

I am going to flush the system tomorrow and see what happens then.

Cheers
Derek

 

my friend is having the same problem its really irritating!!! could the water be leaking from the turbo as it only loses water on boost and the turbos are water cooled?????

 

Mine was a blown headgasket, the heads had be be skimmed as it was warped between the water jacket and the Cylinder an all 4 pots.
It was only using water on boost, this is due to the pressure from the cylinders being forced into the water system.

All done now and the car goes better than it ever did.

 

I had head gaskets replaced on my STI, but the pressurisation had forced a split into the top seam of the header tank, it was really hard to spot at first but was losing coolant, mostly as acrid steam in the beginning (because of the evaporating coolant). Got a forge one now, problem solved.

Have you noticed any steam at all, or am unusual smell in the cabin when driving with heaters on?

 

I've had some fun with the coolant on mine. It is a 2.5 transplant, and the first time I lost a headgasket the header tank emptied quite quickly using excessive boost and ignition, with a few tinkles of det (had a knocklink). There was coolant down the left side of the car. The head studs were a bit slack coming out, there were exhaust gases in the coolant, heads seemed flat and the headgaskets were replaced with head bolts and thinner headgaskets. 7000 miles later with further high boost (25 PSI) methanol fuelled fun they went again in the same way, the header tank was gurgling.

On the latest engine I have been a bit more sensible and have used a larger turbo, no methanol and until recently kept the boost in check. Even then, after a gentle drive the turbo will boil its coolant after shutdown and bubble through the cap into the expansion tank. After a harder drive it will bubble with the engine still on, and the header tank will empty about half way to increase the level in the expansion bottle. But I am not having to top up coolant, and the level is reclaimed over time. Solutions I've found have been to run the expansion tank nearly dry when it is cold so there is plenty of room for hot expansion. I've also fitted a bigger radiator, weaker coolant mixture, cooler stat, water wetter which has reduced the chance of detonation and cooled the oil temperatures but it still bubbles.

I don't think it is the headgaskets because I could get the header tank going lower at only 1.0 bar on the bigger Garrett turbo, and can run it at peaks of 1.8 bar yet I still don't have to add water.

I think the Garrett turbos in particular like to boil their coolant, probably even when the engine is on and water is circulating.

Whilst my engine is going well and not requiring coolant top up, and not overheating I'm not tempted to pull it again.

Not sure how this helps as my car is quite modified. A reasonably modified 2.0 even with a FMIC doesn't push the coolant as much but the temperatures are lower. The most I've seen one do in road use is to bubble slightly with the engine still on which settles as it cools.