Internal Oil filter support spring, fits between the bottom of the bowl & the 3/8" flat washer that supports the flat rubber washer, this spring is often thrown away when emptying the oil filter bowl by people who are not familiar with old fashioned element oil filters, often with disastrous results.

We recently had a 4.2ltr E Type that belongs to a local retired Ex Marketing Director of Jaguar themselves, with a badly damaged engine that the owner had serviced himself - he won't be making that mistake again.

This is the 4th item that fits on the cente bolt, no 5 on our drawing under Technical - Oil filter assembling