losing coolant rapidly

[gary dw 10]

hi all. has been hapening for a while now and cant seam to get my head around it. i no the vr uses a high pressure coolant system anyway but myn keeps dumping alot of coolant out the header tank. iv tried bleeding the system several times with no real issues and the heater works consistantly (hot/cold). it seams after every tank of petrol it will need the expansion tank topping up as the warning lamp indicator flashes. no water on oil cap or dipstick so not really sure where to go next. anybody have any clues. thanks :bonk:

[Jim 1]

What colour is your expansion tank cap - blue or black?

[gary dw 10]

blue.

[Jim 1]

So are you saying you actually get steam coming out of the expansion tank, or does the coolant just disappear after you've done a few miles?

[gary dw 10]

i dont see it escape. there doesnt seam to be no steam. i put some blue towl next to the expansion tank. there is a small hole next to the suspension turret and the rag was soaked next time i cheaked it.

[floppyman 0]

O no...... Head gasket!!!!

[Jim 1]

i dont see it escape. there doesnt seam to be no steam. i put some blue towl next to the expansion tank. there is a small hole next to the suspension turret and the rag was soaked next time i cheaked it.

 

Well then it sounds like there may be a leak in the expansion tank or the cap. I'd possibly replace the cap, and if not that the expansion tank..

[gary dw 10]

dont think its head gasket or there would be that milky mark on the dipstick and or oil cap. thanks il try a new cap first. what sort of pressure do the hoses normally get to. when its hot i cant hardly squeeze the top hose at all.

[floppyman 0]

dont think its head gasket or there would be that milky mark on the dipstick and or oil cap. thanks il try a new cap first. what sort of pressure do the hoses normally get to. when its hot i cant hardly squeeze the top hose at all.

 

You only get the white stuff if its leaking with oil.... Looks like your head gasket is leaking to the piston side

[gary dw 10]

i see what ur saying. il have a good look around the head. might be leaking under the manifold or behind by exhaust manifold were its more difficult to see.

 

---------- Post added at 4:57 PM ---------- Previous post was at 3:40 PM ----------

 

just been out for a drive and to the jet wash as it is nice weather. when i got home i had a look under bonnet. couldnt see no leak from head gasket at a quick glance but the header tank was hissing so does seem like the seal has perished or not sealed properly. looking at the cap tho there isnta seal on it. just a real thin band around the neck of the header tank neck. doesnt even look like it touches the cap. should there be a seal there?

[VW_OwneR_85 1]

you need to identify where this leak is , if its a big leak then there should be signs of it under the car , i.e dripping!! so putting cardboard under the car might help ,

follow all the hose thats related to the cooling system, starting at the expansion tank, use paper tissue/towel around joints etc to see if it soaks up any moisture from the leak,

maybe replace your expansion tank and cap as there cheap parts anyway.

[carrots 1]

sounds like head gasket to me or even a cracked head

[Nathan Harvey 10]

Just been out to mine , it's been out today the tank isn't hissing untill I unscrew the cap a little . So I think you cap seal has gone and coolant is evaporating away . Here's a picture of the spare one I have [ATTACH]61797[/ATTACH] there's a seal in the middle I presume yours is not there or perished hope this helps

[robo22sri 10]

Have you done anything to the cooling system? changed coolant etc

 

Could be a big air lock!

[G11 OWL 0]

Before you go spending big money, I have the same problem. It is not the head gasket. There is a channel moulded into the header tank. When the cap raises under pressure the water escapes and flows through this channel and out under the bottle behind the battery area. I've changed all parts people have listed. Its not a split bottle, its not a failing cap. However I just read that there is an electric water pump in the coolant system somewhere and if this fails it causes excess pressure in the system, air locks etc. Does anybody out there know if this could be the case? I need to top water up every 30 miles or so. Engine doesnt over heat and there is no loss in performance. Is this your symptoms aswell?

[Mr Edd 10]

Had a very similar issue it was the cap with mine. Seal wasn't gone, the valve was stuck open and the system did not pressurise, as soon as the water hit boiling point it dumped a load of water out the overflow.

 

Spent £10 on a genuine replacement. Its worth a try for the cost of a replacement.

Edited May 6, 2012 by Mr Edd

[gary dw 10]

got another cap of a mk 3 golf gti. fits ok so will se how it goes for now, not heard of this water pump mentioned above. anybody else heard of it? if i dont get no joy il try a new cap as it will be the cheapest place to start. my symptoms are the same as mentioned by g11 owl tho.

[G11 OWL 0]

Ive looked it up. They are on there. There is the mechanical water pump and an elecric water pump or auxillary water pump which circulates the water when ignition is turned on and apparently if your fan is running when you switch off the engine, this pump continues to run aswell. Dont know if this will be the cause but I will get it off tomorrow, and check it out. 2nd hand go for 30 quid ish and new are 55 so chances are I'll get a new one in and let you know if it cures the problem. I tried 3 caps, a new bottle, new thermostat and mechanical water pump, rejointed hoses, new jubilees and still no joy. One thing is for sure, headgasket is fine as the performance is still there. If you had water getting into your combustion chamber you'd have poor performance and you'd see rusted spark plugs. If you just had water leaking from a water bore to atmosphere you wouldn't loose it at the rate you are. I'll let you know how i get on xxx

[gary dw 10]

ideal thanks. i got a new cap today. 9.22 inc vat so couldnt complain at that. asked about this electric pump and they said it would be 102.58 + vat on top! am i looking at the right part. the part no he gave was 251965561b. also where is the electric pump situated.

[G11 OWL 0]

Don't pay that much! They are £55 new on ebay. People selling them for 30 quid seconf hand on there. Don't know the part number sorry. I'll let you know where it is as soon as I find it! Infact check this - you can't go wrong! http://www.youtube.com/watch?v=h4sAz3qM5fE

 

Good luck

[gary dw 10]

looked on ebay and they all seam to be american sellers. vid gives a clue to its location lol

 

---------- Post added at 10:42 PM ---------- Previous post was at 10:40 PM ----------

 

does yours sound like that does it, mine doesnt

[G11 OWL 0]

Mine doesnt sound like that - because it doesnt seem to be working, I'll take it off tomorrow and test it. But currently it's not doing anything. I'll keep you posted. Google them and there are motor factors selling them in UK!

[gary dw 10]

any luck withe the pump?

[gary dw 10]

went to my local mill auto and the aux pump is 30 quid. checked water today and it was low, as i was undoing the cap ot fill it i got the usual burp back but this time before the cap was fully off it shot a load of coolant out the small spout at the side. does this mean excesive pressure some where.

[carrots 1]

headgasket mate