Randomly thowing water out.

[pfield69]

I have a random problem on my van, every now and then it decides to thow all its water out the back.

I've checked as best I can the head gasket and it all appears good. An example is late last year I drove to Cornwall. I drove for an hour and then it throw the water out. I let it cool, refilled, simple bleed, then drove it for at least 700 miles over 2 days without it losing any water.

I had a major service/ repair on the van pre-off roading it. Some coolant problems were found (thermostat housing had been repaired, some pipes seated at joints etc). All was fixed. I've been starting her up over the winter and its just thown the water out again.

Any ideas what could be causing this?

[camper]

Diesel or petrol engine?

[Ian Hulley]

Incorrect bleeding ?

[CovKid]

Sounds like its being sick.

[Ian Hulley]

Sounds like its being sick.

Probably an oil burner then

[pfield69]

Engine is petrol DG. Its not using any oil or water except when it throws it all out. It is coming out the filler tank but I presume this is because the expansion tank is opening the pressure cap?

When I bleed the system I do it my partially filling with thermostate bleed off and rad bleed bolt out. I then start it and let it ideal until the van comes on before slowly adding more water. I continue until water comes out radiator bleed when i close the thermostat housing then radiator.

I'm guessing there may be a small leak somewhere allowing air in that eventually causes an air lock.

[Ian Hulley]

Over pressurising the header tank, the dalek cap opens and overflows the top-up tank (behind the cat flap).

[pfield69]

Over pressurising the header tank, the dalek cap opens and overflows the top-up tank (behind the cat flap).

That sounds like it but why??

[Ian Hulley]

Incorrect bleeding, air in the system is the usual culprit although could be any number of things .... at least the cap's working though.

[pfield69]

For the record, the last bleed etc was carried out by Beetlelink. I presume they know what they are doing.

[kevtherev]

Presume and assume?
I'd rather KNOW it's right.
There's an excelent bleed method on Brickyard.

Takes ten mins... or so

[California Dreamin]

Personally, I would be fitting a 'Genuine' Darlek cap on there just to be sure.....
Whats your temperature gauge doing when it's sick?
Is your electric fan kicking in?

Martin

[pfield69]

There are no other symptoms. Temp gauge is normal (always reading quite cool). I changed the temp sender and thermostat just incase. The fan appears to work, when on idle it appears to come on regularly. I have had to change the expansion cap as I broke the little valve. I have flushed out the system last summer. It appears to be very rusty with the water alway very orange. no eveidence of oil in the water and no water in the oil.

Like I say, I can see no leaks. Heater gets hot.

I'm lost

btw, it was genuine VW darlek

[California Dreamin]

Obviously the orange coolant is not a good sign and indicates running with very little antifreeze for long periods. The antifreeze contains anti corrosion inhibitors amongst other things, it stops your engine and cooling system components corroding from the inside.
If this was being diagnosed professionally then I suspect the next step would be to carry out a cylinder leak test, where each cylinder is subjected to air line pressure in order to see if pressure is able to escape into the cooling system.
Deep cracks between the valve seats have been known to cause pressurising of coolant..


Martin

[pfield69]

Thanks Martin.

I have had the heads pressure tested as part of the head check. My first suspetions were head gasket or similar but the over pressure appears too random. It can go for weeks with out doing it. but then do it only after a couple of trips. Sometimes just on idle (as it did the other day whilst just running her up) and sometimes on long journeys.

I don't know how to treat the cooling system now. I always put anti freeze in and the right measure (which is costing me a fortune when its spat out). The corrosion must be from a previous owner.