boxsey911

If you want a new one they're only £11.46 + VAT from Porsche.

CBR786

Okay in garage looking at cap now part number us 100% as follows
944.107.191.04 I think someone might have swapped caps while my car was sitting at Independant??

Aww well gonna probably replace as it does not thighten it tries then loosens after 1/5th turn on full thight like a cross threaded nut would ?

CBR786

Thanks to boxsey

Mine does the same. You can fix it with a hose clamp. Put the clamp on snug and try the cap. If the cap still slips remove the cap and gently tighten the clamp. Keep trying until you get the cap so that it tightens without going too far.

This fix has done the trick for now

CBR786

£11 is reasonable might put it down on next order of stuff along with gasket for airflow meter & probably few other little parts thanks for advice I knew it was not right because it should not loosen like that infact when it loosened it could just be lifted up off the neck without unscrewing to undo .

Makmov

That is just not a good part number so I don't know about that. He is probably just reading one of the casting numbers from one of the parts that makes up the oil cap assembly.

g60pops

euro car parts also sell the oil cap

Metal Guru

Check the top of the fill neck itself for damage. Many get damaged by ham-handed mechanics when filling up the engine with oil.

It's a crappy design: a fill neck that's welded to the body (replaceable on the 993; WTF?) and an o-ring instead of a flat washer as a seal in the cap.

Sometime before spring I'm going to try to make a flat washer to replace the o-ring and see if this improves the situation before performing major surgery and replacing the neck itself.

warmfuzzies

Hello.

Metal Guru

BTDT.
Problem is when the seal surface of the fill pipe is damaged, the height of the thread/sealing surface gets lowered and the cap runs out of thread before it puts proper force on the o-ring. A new cap won't solve the problem, only a new pipe.