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Coolant loss, any idea's? - Skippy
Help!

I?ve been losing excessive coolant from the system of my 1997 Audi A4 Tdi.
It started as a small amount about 6weeks ago so I?ve had it in to the main dealer, they say it passed a pressure test and chemical test, but changed the expansion tank and cap, as they thought the seal could have been dodgy.
The problem has become worse, to such an extent I?m loosing 1 litre of coolant every 30 odd miles, and I?ve stopped running the car.
The coolant seems to be coming out of the expansion tank vent, and pooling on the engine protector cover. I guess this is happening because the system is being pressurised by a leak somewhere.

A friend who works for VW say's he's never heard of this problem with this engine?

Audi say the next step is to pull the head.

I don?t want to pay for this and the problem is something else.

Any idea?s?

Cheers, Skippy
Re: Coolant loss, any idea's? - Eleanor Coughran
It's more than likely a head gasket or head problem, you can't really avoid pulling the head to inspect. The pressure test result is curious however.

Eleanor
Re: Coolant loss, any idea's? - Andy Bairsto
A long shot but this happens when the radiator is partially blocked or the thermostat is stuckallowing the pump to back pedal all the coolant out of the header tank. Have you any creamy like substance visible when you remove the oil filler cap this is a sure sign of head problems.
Re: Coolant loss, any idea's? - David W
Sk,

Bit odd this one. The pressure test should find any external leaks and detect a blown head gasket. I guess the chemical test was for signs of combustion products in the coolant, another head gasket test.

If both of these are clear it is worth double checking the simple basics of a thermostat sticking now and again (as Andy mentions), as the engine reaches the temperatute when the coolant should circulate through the radiator this can cause a furious boiling from the overflow.

I've been asked to quote on a head gasket change before now because another mechanic has said the fault is a certain failure in that area only to actually find a stuck thermostat.

Hope you're lucky with yours.

David
Re: Coolant loss, any idea's? - Brian
I had a similar problem on my Orion which was due to the non-return valve on the little bleed tube into the expansion tank becoming blocked.
Suggest check that all the little tubes are clear to eliminate that possibility.
Re: Coolant loss, any idea's? - Big Vern
Brian wrote:
>
>..... Suggest check that all the little tubes are clear to
> eliminate that possibility.

I have found small pebbles in my header tank before now possibley due to the coolent being topped up from a hose connected to mians water in the past, which can introduce small stones / pebbles.

Anything is possible!
Re: Coolant loss, any idea's? - Rob F
Sticking thermostat was precisely the reason why my 'new' Golf GTI (mk2) was a few hundred quid. Previous owner had head gasket replaced on garage's advice. Coolant continued to spurt out the expansion tank - "It doesn't like traffic". Owner didn't realise the temp needle should live at 12 o'clock, not 10.

Still, garage thoughtfully changed the valve stem seals, 'while they were there'.

Regards,

Rob F
Re: Coolant loss, any idea's? - Rob F
Sticking thermostat was precisely the reason why my 'new' Golf GTI (mk2) was a few hundred quid. Previous owner had head gasket replaced on garage's advice. Coolant continued to spurt out the expansion tank - "It doesn't like traffic". Owner didn't realise the temp needle should live at 12 o'clock, not 10.

Still, garage thoughtfully changed the valve stem seals, 'while they were there'.

Regards,

Rob F
Re: Coolant loss, any idea's? - Pete
If it is easy to get at why not run it for a while with the thermostat removed or remove it and check the temperature at which it operates. Some cars have thermostats which fail shut, stop circulation and wreck engines in seconds - early BMWs had this undesireable function!
Re: Coolant loss, any idea's? - Alan Clark
Is with Pete here. Completely different beast/league/world, but a long time ago, I had similar problems with my first baby, a sound Hillman Avenger! Best and most reliable answer was to drill a small hole in the thermostat as a permanent bleed. Not what you would expect to do on such a modern car, but needs must, maybe. That, or check your watering can for snails...been there...done that too...!!