When working on the oil pressure sending unit (damn unit, I changed it and it's still reading low from time to time, I got to tackle the wiring I am afraid) I noticed a bolt was missing at a critical location. It kind of scares me but maybe it's normal.

I have attached a picture.

Would anybody be able to comment?

Thanks,

 

hmm...looks like it is right next to the coolant drain plug on the intermediate housing, only thing is on my 12As the only thing there is the drain plug. anyone?

 

I actually managed to get hold of the guy that did the engine rebuilt (was not done under my ownership so that's why it was difficult to get the information) but it appears to be normal, Mazda apparently have been using the same castings forever (...) so there are lots of unused holes.

Thanks for your feedback Mortiky