I've just had the head gasket replaced on my '97 A3 - thought I would go through what happened in case it's any use to anybody else. Apparently it's very unusual to have to change the gasket/cylinder head on the early A3s.

Symptoms:

1) Very gradual coolant loss
2) Engine running rough after startup for a few seconds
3) Later on I discovered the sweetish smell of coolant in the exhaust. You also get denser, whiter steam.


Diagnosis:

If you've only got (1) happening, it's possible that the problem is a general leak in the cooling system or the oil intercooler leaking, but if you've got (2) and (3) as well that means coolant's getting into the combustion chamber(s).

The local Audi dealer repeatedly pressure tested the system but there was no loss of pressure, however (2) and (3) above meant it had to be either a blown head gasket or cracked cylinder head.


Result:

Fiendish amounts of money expended on having the cylinder head off and skimmed to flatten its surfaces, replacement of the head gasket and all the associated gaskets/seals. I don't think this is something you can do by yourself, unless you happen to have a fully equipped garage! The head gasket turned out to be blown as expected.

I felt it was best to get it sorted early because it was only going to get worse. There are additives for the coolant which are supposed to seal leaks, but they also apparently have a clogging effect and can screw up the heater matrix.

Hope this is useful - anyone got any comments or alternative suggestions for other unlucky Audi drivers?