Oil filter base o-ring

Here is an article with pictures on the problems with the oil filter housing base seal. Been fighting this for years and decided to write it down with pictures. Hopefully will help out. Feedback is appreciated.


Good stuff Dick. Mine is still dry. I’m travelling right now but when I get back, I will go to NAPA and get the one you recommend.

Thanks Dick.
After purchasing the seals from the regulars I too discovered that WIX supplies the correct one.
Once again, how is it possible these suppliers can’t copy, replicate such a simple item ?

Now that Wix has been acquired by Mann Corp., let us hope they still do.

Surely you have noticed that a lot of aftermarket stuff is not accurate. Unless you call the manufacturers on it, they have no need to change. The oil base fitting issue is nothing new if you search the archives. When people start buying the filters with the rings that fit and quit buying the others, then maybe they will notice. What would be nice is if someone could make a large batch of the rings as the aftermarket filters seem fine other than the ill fitting rings and they are a good bit less expensive. With engine rebuild prices starting in the 15-20 thousand dollar range, it does not make sense to try to save $5.00 on an filter with an incorrect fitting seal.

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I manufactured seals to the correct size years ago when filters kept coming with the wrong size. My recollection was that most filter manufacturers were substituting 1mm and 3mm wide seals at the time. Jaguar supplied filters with the correct size well after the others but that could just be that they were selling from an old batch. I wonder if any supplier that is providing a filter with the correct size sealing ring is supplying older inventory.
The same problem exists with the early XJ6 and XJ12 cannister filters being supplied but I have tons of older inventory with the correct seals so didn’t need to have those made.
Two suppliers bought a large number of my seals so are, or were, supplying correct seals. At least one of them shows a picture now of what appears to be a 1mm seal so who knows at this point.

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Hi Dick…it would be great if you could add all dimensions of a correct seal to your artical.(width/depth/diameter outer)…then anyone could possibly purchase from a seal supplier…this would help anyone unable to get the WIX in their country…i assume a correct size would be available… Steve

I will add dimensions. BTW: the 51183 Wix filter is sold on Amazon and others so not hard to come by. Not sure there is anywhere in the world that Amazon does not service at this point.

I just looked at the WIX website. They list the dimensions of both gaskets (O-rings) that come with the filter.

IIRC, you want the larger of the two, the number 15122.

Here is greater detail on that O-ring:

It is possible you might be able to buy the gasket only at O’Reilly Auto Parts:

WIX Nitrile Rubber (NBR) Oil Filter Gasket 15122 | O’Reilly Auto Parts (oreillyauto.com)m

These people also seem to have them, but who knows what a “Special Order” means.

Wix Engine Oil Filter Gasket 15122; | Star / PerformanceParts.com

the smaller of the two on the Wix site is what you need. .125" cross section will not fit in a .100" groove. Nice information though.

So its not a 0.100in ring…its just a bit less…but importantly it works…Steve

Ah, thanks for the correction. I see the smaller gaskets are also available.

Wix Engine Oil Filter Gasket 15121; | Star / PerformanceParts.com

Yes, many for sure like the 4 IRS mounts.
Called them, mentioned it, showed them photos (compared to the original ones) and was told I had the exact replacement for the original ones. Unfortunately I don’t believe I had an option as they probably all come from the same place.
Fortunately, however, I kept the original ones which appear to be perfectly ok and could be reused if I ever feel like reinstalling them.

I’ve been using the Napa Gold 1183 filter for years and it works just fine. I have a couple of gaskets sitting around, one is about 0.125" thick and the other 0.090 so consistent with the WIX info that John posted.

Made by Wix…:wink:

When we used to have rubber seals made, there was a 10% -+ tolerance. I was measuring the actual seal. Nice to see the real specs from Wix. .093" is a lot closer fit than the .065" that comes with the standard filters.

I have a Tecalemit filter housing from a 3.8 E-Type (Filter No. FA2746) right here.

The sealing ring groove is not exactly .100", it’s actually tapered. It measures .1125" wide at the top and .075" wide at the bottom. The depth is about .30".

The old sealing ring that I removed measures about .075" wide X .13" deep in its compressed form and has one yellow stripe on its OD.

The problem here is that the original seal dimensions don’t match up with any modern standard. If you measure the oil filter can and the groove in the base and compare those dimensions to modern AS and ISO standards, you can see the problem. I assume that oil filter can size dates from before WWII and any standardization. The seals I manufactured are 3/32" wide and 3/32" tall to match the originals I have in stock from the 1960s.