cooling system problem 8v gti

[midz16v]

morning all,
I got a shot of a mk3 gti til my mk2 is fixed but it has a problem with the cooling system,when i first got it i drove it back to my house 4 miles away.
When i parked up i noticed steam comming from the engine bay,popped the bonnet and water was boiling out of the exp bottle.
Next day i flushed the system out and filled the car back up with coolant,left the cap off and started to bleed the system.
As the engine heated up and i was getting the air out of pipes etc,the water would start rising in the exp bottle till it was comming out the top,then when the fan cut in it would drain the exp tank so i had to put more coolant in, when the fan stopped the water would slowly start overflowing again til the fan cut in again.
All the pipes get hot and the air runs hot inside the car.
Does anyone have any ideas as to whats wrong?

[Horney]

Could be headgasket letting air into the system.

Nick

[midz16v]

my mate thinks this too,is the headgasked hard to do?apart from headbolts and gasket what else would i need for replacing the headgasket?

[Rmachines]

Same problem i had,  I never figured it out so i scrapped the car  

They are supposed to be very hard to bleed out sometimes but mine just never worked,  start by changing the thermostat and if that doesnt work, check the water pump,  might be time for a new one.  then keep trying.

if you put the inside fan on full and set to hot it should stop it from boiling over.    

If you think its the head gasket do a compression test first!  if its down on a cylinder then its deffo the head gasket.   they arent to hard on the 8v but it takes time and patients if you have never done it before.  and use a manual... it does help 

[Horney]

I'd also get a rocker cover gasket while you're at it. But that's it. Not the hardest job in the world but I would recomend doing a compression test first to save the hassle of doing to find it was OK.

Nick

[pro-biotic]

headset ftw, will have gaskets and seals for the whole job tbh - no point pulling head off withoug doing the stems..

seeing as you may have combusion loss is there any signs of water in the cylinders, such as clean plugs (as if they have been steam cleaned), the next step would be tp get your coolant annalysed (any good garage will do it) to check for products of combustion in your coolant.

re water pump, are you getting any circulation? i.e all pipes at similar temp - if so discount the water pump, however always good practice to do the water pump at time of cylinder head (especially on diesel pugs)...

if your close i have a nice 2litre gti engine in my shed, ran a dream - would be easier and cheaper than messing about doing the headgasket.

[pro-biotic]

re-read your post...

CHANGE THE EXPANSION TANK CAP before doing any of the above.

[midz16v]

will chance the exp tank cap as mines is the older black one,but cap on or off it still boils over til the fan cuts in then it all gets sucked back into the system,then i have to top up whats spilled out.

[Horney]

The system will build pressure when it's hot, it's supposed to a bit. Try a new cap and see how you go. If no luck then get a compression test done.

Nick