For the record, the O-ring that seals the coil pack housing to the engine is

3.53 x 36 mm

according to the labelling on the genuine Fiat part. I have just replaced mine.

The 36mm is the inner diameter of the o-ring.

I don't think this is a standard metric size, although a 4 x 36mm O-ring might work fine.

This information is for an 8V mk2 engine.

Ok, I'm replying to myself again....

The coil pack o ring is a standard size, it's the American SAE size.

The generic part number is


SAE AS568-236

-2xx indicates series 2 (cross section 3.53mm or 0.139")

x36 indicates 36mm internal diameter.

And again, jumped the gun a bit....

SAE AS568-221

The last two digits are a lookup to the size, not the size itself.

....which interestingly is exactly the same size as a British standard o ring

BS 1806-221

Well, knock me down with a feather, the Americans are like the British. Or vice versa.



Is this a record thread with a huge number of replies to the op by the op?

Finally, you can get them on eBay for peanuts

http://www.ebay.co.uk/itm/221-IMPER...DIY_Materials_Plumbing_MJ&hash=item43a8c8e739

Really finally, nitrile rubber will be fine, it is oil resistant.

Thank you. i managed to find this o-ring today.
only 0.62$ .

Thanks for the details

2¾ years later from your post and that seller appears to sell only packs of 10 for £3.50.

I just fitted the head gasket set from FAI but their supplied seal was smaller and thinner that the original and leaks badly.

Genuine O ring part number: 14463980

£1.94 from my nearest Fiat main dealer. They don't take payment over the phone so have to so there.