CAS oil leak in 97 1.8 NA ??

[Bob_MX5]

What are the tell-tale signs of a CAS seal oil leak versus valve cover gasket versus oil filter/oil pan plug? Tryng to determine where the source is of the spot on the garage floor.

B.

[sammm]

Feel the bottom of the CAS for oil.

[OZMDD]

Truthfully, if you haven't changed the CAS oring yourself or have documentation that it's been done, it is almost certainly dried-out and leaking. It's a design that is prone to failure, and very cheap/easy to fix, make sure you use a Mazda o-ring. Now, rear main seals leak almost as universally as CAS orings, so...

[Bob_MX5]

CAS Oring is original. I'll check for fresh oil there. Hopefully, not the rear main.

Thanks guys,

Cheers.

[Rogue]

make sure you use a Mazda o-ring.

Really?….I have been using .23c O-rings of the same durometer for 10 years, and have installed hundreds……..or you can give Mazda $7.

[Bob_MX5]

Feel the bottom of the CAS for oil.

Yup, oil on my finger tip after the quick feel.

Picked up an O- Ring and cam cover gasket at Oreillys and plan to change both this weekend if it's not too cold in the garage.

B.

[sammm]

Yup, oil on my finger tip after the quick feel.

Picked up an O- Ring and cam cover gasket at Oreillys and plan to change both this weekend if it's not too cold in the garage.

B.

Be sure to mark the CAS alignment before you take it apart. Scribe a line across the two halves.

[OZMDD]

Really?….I have been using .23c O-rings of the same durometer for 10 years, and have installed hundreds……..or you can give Mazda $7.

Really. I've used the ones they give you at vatozone and seen them leak right away. I agree that there is nothing special about the oem, if you can find the correct dimensions and durometer. The generic ones I've found are not correct. I'd love to know your source.

You Back in the miata business?

[Bob_MX5]

Be sure to mark the CAS alignment before you take it apart. Scribe a line across the two halves.

Will do.

Been reading up on it on m.net and my 1.8 workshop manual. Seems pretty straight forward when you pay attention to the details.

B.

[Bob_MX5]

Update:

Spent yesterday afternoon doing the CAS o-ring plus a few other item. The cam cover casket was seeping so I did that too. Also, because we know a cas oil leak can and will destroy a heater hose, I replaced both of them. Finally, because the opportunity presented itself, 4 new spark plugs were installed.

Some thoughts..
No cam cover in place makes o-ring install easier. Especially if you remove the collar that forms the top of the CAS mounting point. With the collar off, you can fully remove the CAS from the engnine bay for easy access to the o-ring, and you can the see the slots in the end of the cam where the tangs connect so reinstallation is simple. Just be carefull not to erase your alignment marks from the collar. Also, when the CAS has been fully removed, access to the heater hose clamp at the back of the engine is visible and much easier to access. Replacing the hoses was the only real PITA part of the job.

If you're slow and somewhat methodical (like me) you'll spend several hours from start to finish doing all this stuff. I spent extra time cleaning the cam cover, inside and out, before re-installing it. Plugs needed to be gapped and wires needed to be labeled. Mating surfaces needed to be cleaned carefully. Also, coolant needed to be drained and then refilled. Overall, these are relatively simple but time consuming maintenance items and only require basic hand tools. A great opportunity to get to know your miata.


B.

[MC70]

Nm...