coolant leak

[marko65]

Had to top up coolant with 1L after the coolant warning light came on- I had checked the coolant the day before so knew I had a leak. The coolant appeared to have escaped via the expansion cap.

Have had the undertray off but no signs of a leak - the coolant loss is definitely coming from the  expansion tank -  this only seems to be the case if driving  - I've had the car idling on the driveway up to running temp but the coolant doesn't escape when just idling.

I've taken the expansion cap off and brought the engine up to operating temp but there doesn't appear to be any bubbles coming into the expansion tan and it doesn't boil over.

I have purchased a new expansion cap today and fitted it but this doesn't stop the problem.

The heating works fine in the front vents but only cool air comes out of the rear vents.

The car is an 02 plate 1.9 TDi Zetec Mk11

If the run on pump has gone would it cause the problem I have ?


Any help appreciated

[marcushamblin1976]

Sounds most likely to be head gasket. What engine 115 bhp ?

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[marko65]

Where will I find the engine type?

[marcushamblin1976]

On  log book, or white sticker inside right rear trim by light unit, if its auy engine its really common. Its pressurised whilst driving because the head gasket is blown. The relief valve in the coolant cap opens at very high pressures and dumps pressure and coolant out. If you change the head gasket use 150 bhp head bolts , this is a known issue. You will find loads of posts on here with same issue and outcome. 

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[marko65]

Think its 115PS - due to age and cost I think it's time to look for another car if it is the head gasket - I'll get it confirmed by a garage  - Thanks for your help

[marcushamblin1976]

No problem,  you could try a head gasket sealer, unlikely in my experience,  have heard of people tightening head bolts and having success but I think that's risky.  I had this problem on a Bora and a Sharan.

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[johnnyroper]

AUY is the 115bhp unit and from what you describe it is likely to be head gasket, worth checking the restrictor in small bore hose to expansion bottle isnââ,¬â,,¢t blocked though,water pump impeller can also come loose on shaft but I feel this is unlikely to cause the issue you have.

[marko65]

I dont think its the small  bore hose as I can see coolant coming through the end into the expansion tank when the cap is off (not sure the amount that should be coming through - it's a trickle)

Thanks again

[marko65]

any recommendations on a head gasket sealer ?

[brianh]

I dont think its the small  bore hose as I can see coolant coming through the end into the expansion tank when the cap is off (not sure the amount that should be coming through - it's a trickle)

Thanks again

Dribble is around what you should get - if theres a problem you get nothing, its only a bleed circuit to allow the air to get to the top of the system, but if the impeller isn't working (or the hose is blocked) you won't get anything at all through it.

[johnnyroper]

any recommendations on a head gasket sealer ?

Donââ,¬â,,¢t waste money on any of those products it wonââ,¬â,,¢t fix head gasket leak but can cause blockage in rad and heater matrix.