UrS6 - Loss of Coolant Query

[macspring]

UrS6 is loosing coolant, can't see that it is escaping out of any rubber pipes or the header tank etc. although I may need to check in more details.

Query is can the engine 'use' the water at the head gasket area, but still drive and pull as one would expect ? The engine oil is 'black' in colour rather than any hint of mayo.

The matrix is not leaking as far as I know as the carpets are bone dry.

I thought I could smell coolant under in the engine bay after a 5k journey, but couldn't see any leaks.

It needs half a litre in say seven days approximately. Sometimes the dash temperature gauge takes it's time getting up to the normal 90, and other times if gets up there as normal.

Going to change the thermostat, the MFTS, and the white temp sender at the rear of the engine anyway as they are all probably originals from when the car was new.

Any ideas or comments re the water consumption ?

Thanks.

[UrS4boy]

20VT Potenial coolant leakage locations

1. Head gasket - obvious. Sometimes possible to observe bubbling in overflow tank due to compression leakage.

2. Any of the coolant/HVAC hoses http://forums.quattroworld.com/s4s6/msgs/301760.phtml



3. The water manifold gaskets http://forums.quattroworld.com/s4s6/msgs/301767.phtml

4. The hoses under the intake manifold



5. The turbo coolant feed line http://forums.quattroworld.com/s4s6/msgs/72682.phtml



6. The after-run pump http://forums.quattroworld.com/s4s6/msgs/21503.phtml



7. The casting plug at the back of the head http://forums.quattroworld.com/s4s6/msgs/319651.phtml



Photo courtesy of Newsh on the S2Forum

8. See the link in item 2 above for anything that I've missed

[Cordoba16vt]

If you are on the original headgasket and it is not the metal one - they fail with age and antifreeze gets into the cylinders and it gets burned away. It is more likely to get into the cylinders rather than in the oil passes.

[macspring]

Did the later AAN engines not have metal gaskets from the factory ?

Car is a 1996 model year.

Thanks.

[Cordoba16vt]

I think all 95.5 cars onwards had what i call paper gaskets... my car is 1996 model and failed. One sign of such failure is reddish colour of turbo exhaust side and spark plugs....

[Thuppu]

My orginal paper headgasket leaked only when engine was cold and it leaked water to the outside, dripped on the exhaust manifold.

[cadiddy]

Have you done a pressure test on the coolant system? Sometimes this helps when joints can't be seen properly from above.
Also if there was a leak into one of the cylinders due to failed HG would you not expect white smoke?

[UrS4boy]

Head gasket changes from composite to all metal

Did the later AAN engines not have metal gaskets from the factory ? Car is a 1996 model year. Thanks.

The original UrS AAN engines came with a combination "paper" (impregnated fibre) and metal head gasket, i.e. a composite head gasket. The PN for this composite headgasket number was 034103383AB. When I asked my good friend Kate about that PN, she says:

"Dropped on 30/09/1994, please use as replacement: 034103383AD". 383AD is the all metal headgasket and now is the only good PN in the system, for the 3B, AAN, ABY and ADU.



Composite head gasket:



All metal head gasket:



REFERENCE: http://forums.quattroworld.com/s4s6/msgs/246426.phtml

[macspring]

Is there away of determining which is fitted to an engine without taking the head off ?

Is there a sticky out bit of the fitted head gasket that one should look for to be able to determine composite or metal ?

Thanks.

[Cordoba16vt]

Yes there is on the exhaust side if the engine. Need a shaprp tool to scrape it a little.In any case you should consider a head off job. What is the mileage of the car?

[mcandmar]

As above, those two brass rivets on the exhaust side poke out under the exhaust manifold, just grab them with a pair of pliers and see how flexible the gasket is.

[220bhp]

Get coolant sniff tested to see if its the head Gasket.

[macspring]

Update, pretty sure it is the after-run pump, which I felt was pretty new, but anyway an easy cure.

[UrS4boy]

After-run pump info link

Update, pretty sure it is the after-run pump, which I felt was pretty new, but anyway an easy cure.

http://forums.quattroworld.com/s4s6/msgs/21503.phtml

[macspring]

Thanks Dave, again.