expansion tank overflowing

[david106]

I came home tonight reversed onto drive and got out of the car and i could hear water running
so popped bonnet and the expansion tank was peeing out water from the overflow
Now im not sure how tight the cap was would this cause it or do i have another issue
Its dark now so i cant see whats gone on but i did top up the water so will see what it does in the morning.

engine is a 3.2v6

[jonnybravo]

Hi David
hope that your cap was loose as it sound's like your cooling system is presurizing usually caused by a blown head gasket,faulty water pump or faulty thermostat.

[jonnybravo]

...

[GSiFan]

Any joy? Paul

[ph67]

I agree with what JonnyBravo says, had the same problem on my V6 diesel - is there any pressure in the system when it's been left overnight and it's cold? If so then sadly there's only one place the pressure is coming from and that's the cylinders - you probably won't find oil in the coolant or coolant in the oil either (I didn't) - better get a compression test carried out (at least you've got spark plugs that can be taken out to carry out a pressure test!!!))....of course, it might not be iff you've replaced the coolant lately and not bled out the air properly, but you'll know that if there's pressure in there when it's cold.....good luck.

[david106]

little update
got up in the morning and topped up the water and went to work about 16 miles and the temp gauge didnt budge off zero and it was the same coming home
yeseterday it did get up to about 80c for a bit .
When i had a quick look down the side of the engine where it meets the gearbox there are signs of water marks

[Stebo1212]

I have this problem with my 1.8 now i saw the comment about its pressurising the system from who iv spoke to about mine so far the cooling system is meant to be pressurised is this right as the pressure in the system is what raises the boiling point and stops it from boiling etc

[Slammedorion]

Good 4 year bump ... lol

[GSiFan]

The system is meant to be pressurised. Yes. Hence the spring-loaded expansion bottle cap. It is not meant to pee coolant out the bottle, though. Was the cap on properly? Nice and tight?

Paul

[Das]

Yup the system is pressurised to keep it from boiling. Start with a new expansion tank cap first, if its not that get a sniff test done to rule out head gasket failure.

£4.41 of ebay.

http://www.ebay.co.uk/itm/Genuine-OE...MAAOSwMtxXswNq