mk3 ABF coolant* boiling over

[Wayne]

First try changing the expansion cap.

+2 I would do this as a 1st step.

[AudiA8Quattro]

If the coolant system is overpressuring so quickly i would suspect the headgasket.
Try slowing releasing the pressure by undoing the cap, be careful not to get scalded.
If the system pressurises really quickly again then i would say the headgasket has gone.

[VWstevo]

If the coolant system is over pressuring so quickly i would suspect the headgasket.
Try slowing releasing the pressure by undoing the cap, be careful not to get scalded.
If the system pressurises really quickly again then i would say the headgasket has gone.

Mine was doing the same matey, i changed the expansion tank for a new 1 and a new cap, still did it, new head gasket fitted 4 days ago and lots more lol. Had a new thermo and water pump fitted and still did it, Had a compression test done on it today this was fine. Me and my mechanic mate messed around with it for hours today draining the system and filling it up again god knows how many times we did this and still it pressured up.

The hose at the top of your expansion tank when you take it off is there any water coming out of it also the small hose where the ecu sensor is located just at the front of your engine block the one with the hoses going into it. The smallest hose just to the right of this little housing take this hose off and check to see if the water is coming out of this housing. On mine it wasn't nor was it coming out of the return hose at the top of the expansion tank. We think we eventually found the problem it was a blocked pipe the small one i mentioned coming of the little housing this was blocked with some hard crap which we had to force out. Touch wood this as solved the problem. The water level now stays at max. Hope this helps buddy. Steve.

[aminorthreat1]

right i'll check that, im pretty certain the head gasket is fine, i spent long enough testing it and i had no probelems at all before i changed the coolant. i've also ordered a new header cap. cheers for the help.

[aminorthreat1]

right, just started her up, coolant boiled over before it got up to temp. the heaters are now only blowing cold, and there doesnt seem to be any coolant moving around the system at all. im guessin its the thermostsat or the pump, so i might aswell do both.

[rubjonny]

as stevo says, check the thin hose. with the cap off run car from cold, when you rev engine there should be a spray of coolant out of this thin hose to the top of the header tank. if not the thin hose is blocked, or the waterpump is knackered.

[VWstevo]

as stevo says, check the thin hose. with the cap off run car from cold, when you rev engine there should be a spray of coolant out of this thin hose to the top of the header tank. if not the thin hose is blocked, or the waterpump is knackered.

Amino

Just an up-date mate, mine still ok the water level staying at max, if there's water coming out of that hose i told you about then it's more than likely either the thermo or the water pump dude, Water pump £21 GSf thermo £4.

[aminorthreat1]

cheers. hopefully be able to do it this weekend.