Does anybody what the deal is with the replacement coolant caps that come with a wide collar and no o-ring on the insert?

I lost my coolant cap recently.

This what the coolant cap is supposed to look like. It has an insert with an o-ring. It is also a strange cap in that it is very hard to get on and off.





I lost my original and ordered a replacement from ebay. It arrived and has a wide collar which bends up when you screw the cap on. It also has no o-ring inside the reservoir neck. The seal is from a flat rubber ring gasket inside the lid of the cap.



The ebay one also had a thread that did not work so I could not use it anyway.

So I went to the local repco and they sold me one which also has a strange wide collar. Fortunately the repco one has a good thread. But when i screw it down I get the impression it is becoming tight because the collar is pressing on the top of the reservoir (causing the collar to bend up)

Repco is the one on the right. EBay is the one on the left






If that is the reason it is getting tight then it will not be sealing properly and so pressure will not build up to control the boiling point.

I am thinking I should cut the collar off this Repco cap so I can check that it is seating properly and sealing properly. It is just not possible to tell with the wide collar pressing on the top of the tank.

What a saga losing this cap has become.

I have got a 4th one ordered from China which actually looks exactly like the Jaguar original according to the photos so hope fully it does not have a huge flared collar when it arrives.

I don't suppose you considered getting a correct OEM cap from a Jaguar supplier?

SNG Barratt a forum sponsor (discount given if mentioned)




Parts Geek OE part =



E Europarts =

https://m.eeuroparts.com/Parts/46113...p-MJA4440BACS/

it’s a lower pressure variant of the late 90s mondeo/transit cap

use one of those in the mean time

^^thanks for the link. Partsgeek does not seem to ship to Australia though

^Thanks for the Mondeo tip. That might open my options up a bit

If anybody else has been sent/sold a cap with wide collar and managed to adjust it to fit the x-type please post your tips.

I will come back and update the thread once I have solved it at my end.

eBay Australia has plenty of caps on sale from around AUD 26.00 locally, down to about half of that from China. Have a look: Coolant Recovery Tank Caps Mja4440BA for Jaguar x-Type