Engine oil leak (pictures attached) Advice required!


I have an oil leak at the back of the engine (Eunos, mk1), there has been a patch of oil there for some time around the pipes at the back (a few years) but now but it seems worse than ever although that could just be because it has collected over time I guess.

I don’t believe it is a major leak as the oil level was still above the minimum line and the last time I put oil in the engine was a good 3 or 4 months back or possibly more.

Any idea if this is especially serious? Could it get worse, is it repairable?

Any advice much appreciated!


Its the CAS o-ring weeping. Being a 1.8, it’ll drip on those heater hose, softening them, and eventually causing one to rupture, which if you are lucky, you’ll catch as a puff of steam around the nearside headlight lid.

This is the main reason to get this fixed. The part is cheap, and the repair easy (whip off the cam cover)

Given the amount of oil on those hoses already, I’d change them as well, using OE Mazda hoses, not rubbish aftermarket ones.


That looks like a classic case of a cam cover gasket leak.
Clean it all up and you might get a better chance of identifying of the exact spot of the leak.

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Thanks. I’ll have a look online at getting the part. I just watched a video on youtube and there is a high chance it is that.
If anybody knows the best place to get the part for a good price feel free to tell me.



Get the genuine Mazda cam cover gasket, apparently the aftermarket are not as good in this case.

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If DIYing, important to have a low range torque wrench for the cam cover bolts. You can kind of do them by hand, but they are easy to shear, and then you are stuffed.

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Will be my dad or uncle doing this as I’m clueless at mechanics. Hopefully it won’t be too tough a job!

As a novice with all things MX-5 my first job was change the cam cover gasket and CAS seal. I followed this guide below. Remember genuine Mazda gasket, use the silicone at the points mentioned and finally tighten the cam cover bolts in sequence. As mentioned in the above post not too tight but, if no torque wrench as a guide two finger pressure on the final tighten down on your socket bar, it worked a treat for me.


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