I had my car repaired by roadside and mechanic must have took oil cap off and not put it back on properly. I typed in my reg to ebay and bought one for a few quid, that didn’t fit, so I tried another and thats come today and that doesnt fit!

How do I get the right one?

Dealer would be the obvious place to go.

If it’s a modern car with an encapsulated engine bay it may well be kicking around somewhere near the sump.

Other than that – go to a main dealer.

Yeh, or failing that you can probably get a universal one, like you can for petrol caps from motosave or somewhere, try it for size before driving away?

Its a knackered old 2006 Vectra.

Local breakers yard .

Find similar car on Autotrader or ebay, with pics of engine bay.
Note style of cap.
Find same style cap on ebay.
Buy cap, fit cap.

Breakers yard, it’ll be about £3.

Its a knackered old 2006 Vectra.

Have you asked the local Vauxhall dealer if they can get one?

There’s a special code you can use to get the right one if you go to the breakers, or if you speak to anyone actually knowledgeable. Ask for a “seven-ten” cap, and show them the ones you have held upside down.

My local petrol station has a box full of oil and tank caps that have been left.
Just don’t try and plug it with a sock, think that was on a BMW owners forum once. 😆

I read that. Is legendary!