Loss of coolant

[HomerSimpson]

Hi,
I have just bought a 98 A4 Quattro estate, the problem is that it is losing coolant. It seems to be leaking from the expansion tank as I have noticed a lot of water stains in the engine bay, also a wet point under the tank. There does not appear to be any oil in the water and vice versa, also no white smoke from the back. Am I right in discounting the head gasket? If not has anybody any ideas. I did find a similar problem on the VW section, which turned out to be the pressure cap. Can anybody out there help please!!
Thanks in advance.
Dave.

[timnewton30]

Hi Dave, My 97 A4 Avant has the same problem. I have spoken to my colleague Darren who happens to be an Audi Technician of 13 years. And he has told me to buy a new pressure cap.

Mine is chucking water out of the expansion tank and sends the low water warning light on when i go up or down a steep hill. But i must emphasize that it never completely empties the expansion tank. I just top it up to the max level, then after about a day or two its back down to about 1/4 full again.
I have yet to buy the new pressure cap, but from the feedback i have been getting it seems to be the cause of the problem.
Darren informs me that in the cap there is some sort of ring that after time just gives up doing what it's supposed to do.
It's got to be worth a try for the price of a cap.
Hope this helps,

Regards,
Tim

[HomerSimpson]

Thanks for the reply Tim, I had a feeling that the pressure cap was the culprit as I have never seen a blown head gasket spray water about the engine bay! Will try and get one over the next couple of days. Thanks again.
Dave.

[routers77]

I would also check clips that join the pipes to the expansion tank. A clip on mine had broken causing coolant to leak. I just replaced clip with a jubilee clip.

[mrjolly]

i too had mystery coolant loss and it was the cap . get one mate .

[HomerSimpson]

Thanks all for the replys, Have had a better look today and it looks like the previous owner has put some "Bars Leaks" in the coolant. It looks like the top of the cap has become blocked. Have cleaned it out and screwed the cap on properly :aargh4:. Will let you know the outcome, however, now have a new problem, see post "Fan has stopped working" for details.
Dave

[smilin-s]

Hi there ...

Just bought a A4 estate 1.8 20V and have the same problem with the coolant. What does or did it look like in your cars? was it properly spraying all over the engine? ... Also, my water temperature seems to go up fine to around 90 when the car is standing or in city traffic but when I drive cools right down again ... any ideas what that could be?

Cheers Seb

[HomerSimpson]

Hi Seb,
Yes it sprays water all over the engine bay, however the temp goes up to 90 and stays there, it does not rise or fall. The general concensus is that it is the seal on the cap that is gone.
Hope this helps.
Dave.