mirousse

I suspect my fuel cap is deffective.

Can someone show me a picture of the inside part of his fuel cap please. If different cap models exist, my car's an 89.

Thanks.

Michel
89 S4 ROW

Mrmerlin

the fuel caps are all the same.
There is a rubber seal thats fitted to the outside edge of the fuel tank inlet this helps the cap seal.
What is the problem your having??

Mrmerlin

here is a link with pictures.
https://rennlist.com/forums/928-foru...light=fuel+cap

mirousse

The flat exposed inside part of my cap locking mecanism is missing (only the PO would know why). I glued a piece of cork gasket to it just to see if sealing the cap would affect the operation of the car. My request for a picture was to see if there was some kind of venting hole on the flat section because my patch doesn't. Based on the pictures, it doesn't seem to have any, which compares to my temporary fix.

Question: Does the tank need some kind of venting to ensure negative pressure doesn't build in the tank? If so, is it through the gas cap or where is it?

Thanks again.

Michel.

Mrmerlin

IIRC there is no vent on the cap in or out the venting is via the charcoal canister, and the bleed line thats connected to the tank above the RR wheel inside the fenderwell

mirousse

Thanks