CAS oil leak question

[Vissi]

I am working on fixing as many of the oil leaks on my miata as possible.

I changed cas o-ring on my 1.6 around a year ago, but it seems to be leaking still.

I pulled it back off and sure enough, tons of oil back there. The o-ring seemed to be fine, but the mating surface does not seem in great shape.

Is this much scoring normal? Can I just sand it down with some like 2000 grit?


http://imgur.com/a/bS61f

[sammm]

Interesting, don't know if that wear is normal or not. How old is the valve cover gasket? Could it be leaking on that back side?

[Vissi]

It is about a year old, but I have pulled it off a few times since then without replacing it.

When I pulled the cas it there was a ton of oil past the o-ring. I guess it could have leaked down from the valve cover gasket and onto the cas.

I bought a new one to replace with the cas seal because I thought it might be the valve cover as well. (also getting a new cursed water plug just in case)

[sammm]

^Good plan on replacing the water plug whilst the cover is off!

[Bob_MX5]

I've never seen a cap with that kind of scoring. I'd buy a used cap or new if necessary.

Even if you could sand it smooth you'd need to find a thicker o-ring to make up for the missing aluminum. That would be hit n miss.

B.

[OZMDD]

Permatex Ultra Black

[Vissi]

I think I will try sanding it some. I have not had much luck sourcing one.

Just put some ultra black on the oring when I install it? Wouldn't it just break the seal when I move the cas for timing? I plan on putting in on all the edges when installing the valve cover gasket if that is what you mean.

^Good plan on replacing the water plug whilst the cover is off!

Thanks! I keep reading all the horror stories.

[sammm]

I think the ultra-black goes on the edges of the CAS 'cap'.

See pic...

[OZMDD]

In your situation with a badly-scored mating surface, I'd seal up the oring too. Set the timing right away (or before you do this and mark it) and adjust it before the sealant dries. Timing doesn't need adjusting very often.