After a trip of about 40 miles or so in my STI Version 6 all the water in my metal header tank (front left of engine) disappears. There is still water left in the radiator pipes and the car manages to hold temperature (i.e. not overheating) although it probably would if driven for a much longer trip. Strangely the water in the coolant top up tank at the front right of the engine remains steady at the 'maximum' mark. Shouldn't this be making its way into the header tank in order to replace what was lost there? I presume the header tank coolant is either leaking out somewhere or is escaping through a failed head gasket? The latter should hopefully be unlikely since the engine has done less than 3k since being rebuilt with a brand new EJ25 short block. I can't see anywhere obvious where it may be leaking out (split pipes, etc.) but there was some water splashed around the battery tray near the front right coolant reservoir. Could it be that water from the header tank makes its way into the front right reservoir, but is not returned back, and therefore just overflows into the battery well via an overflow pipe or something? Any ideas what I should be checking? I could get the coolant tested for signs of exhaust gases, confirming whether a head gasket has failed, but if there is no water left to check in the header tank and the reservoir is not in play (?) then not sure if the measurement would be valid anyway?!? Thanks in advance for any help anyone can give.

 

had similar problem 2 weeks ago, ended up being waterpump was only leaking when engine was running

 

Have you checked the oil for discolouration? ie water mixing with the oil.
Does the header tank smell of fuel? obviously wait till its cooled down before you unscrew cap..
Do you know any local garages?
If so ask them to do a block test on it to see if any gasses are escaping into the coolant..
I have a block tester ..you can pick them up for £20
Its quite a good little gizmo for checking for cracked heads or headgasket failiure..

 

Thanks Mark. Yes, I have checked the oil for signs of water in there but all appears well, no mayo, etc. Maybe it is a gasket leak to the outside of the engine (coolant loss only) rather than a gasket failure allowing the water into an oilway? The hydrocarbon test was something I mentioned I was thinking about doing but didn't know they were called 'block testers' so thanks for pointing me in that direction - where did you buy yours as I think I'll invest in one.

The thing that seems weird to me is why the header tank runs dry whilst the coolant reservoir is still sitting on the maximum level?!?!

Cheers

 

Got my one of ebay ages ago..
You have PM

 

If a head gasket has gone then it'll boil the water over into the expansion bottle, and it'll probably blow out the top of that and leave the puddle around the battery. Have you checked the expansion bottle for bubbles when the engine is running?

 

The most likely explanation is that one of the end tanks on your radiator has split. Have you checked?

 

No, I haven't checked that... but I will do now! What am I looking for - cracks with water or steam coming out once the engine is up to temp?

I think I did notice some bubbles in the coolant reservoir when I took the cap off to see the level. The level in the reservoir doesn't seem to go down at all as a result though? I'll need to check again (can't start the car up at the moment as don't want to annoy the neighbours at night time) and presumably run the 'sniffer' on it to check the bubbles are exhaust gas. Could the head gasket really have gone that quickly - or is it more a sign of someone putting the engine together badly?

Cheers for all your help guys.

 

had the exact same fault. when pressu re tested water pissed out of the rad! so thinking i need a new one lol any oneknow where to get one cheap for jap wagon lol

 

Hairline cracks appear on the ends of the radiator, as the end tanks are plastic and become brittle. If your coolant is brightly coloured, you should be able to make out where it's coming from. You won't really see much happening, even with the engine running, as it's under load that it's forced out at pressure.

Quality replacements can be had brand new from ebay for around £80-90, and are easy to fit.

 

Hi Chaps,

I've currently got the same problem as Stevie B but with a little twist, the car seems to be limiting itself to 4500rpm, as if it's bouncing on a limiter....if i keep the engine at 4000rpm everthing stays fine and I loose no water, hold it on the limiter for a few seconds and the water comes flowing out the overflow pipe on the coolant bottle beside the battery,
I've done my best to get the temperature gauge up in the red but the fans kick in and keep her cool.....the car is just in from japan is it possible there is a limiter on the engine....

can anyone help......