I originally ordered the original MazdaSpeed MSM oil cap from the US for my SE/MSM because that's the cap they came with in Japan and the US (deleted in Australia because it contained the word "Speed" which might lead to driving recklessly acording to the censors of the time).
Unfortunately this leaked and dribbled oil down the hotside of my rocker cover when on the dyno or dríven aggressively (maybe those "gubment blokes" were right, the word "Speed" when printed anywhere on your car does make you drive more recklessly -yeah, right!).
This leak isn't uncommon and was reported by a lot of guys on the now-defunct mazda-speed.com forum.
I was so annoyed with it I gave it away to a member who offered to pay for it - I wasn't comfortable taking money for something which I knew had a problem. I'd tried to manipulate the rubber seal in several places but it always leaked.
I switched back to the OEM plastic cap but thought it looked too bland so bought the billet aluminium eBay one that many guys here are also using:
- 3-point front strut brace temporarily removed in this shot
- no more leaks
- I chose a darker one rather than the aluminium-colour because it suits my engine bay's colour scheme better.
- for anyone who has issues with oil caps becoming loose at the track, these caps have enough meat on them for you to drill a hole through one of the "knurling points" (I don't know what else to call them) so that you can wire it securely onto something to prevent rotation.
