Have a 90 RX7, 5sp. Put a factory rebuil engine in about 16k miles ago. Has a total of 178k miles on the car. Anyway, it's started leaking oil somewhere from the front. I cleaned the engine several times to get rid of the residue, but have been unable to locate the leak. My brother thinks it might be the front main seal. I've changed the oil every 2.5 - 3.0k miles using Castrol 20w-50. Was going to change
to Mobil 1 15w-50 this next oil change. But it's lost 1/2qt in only 400 miles. Usually
I was only using 1/2 qt in 3k miles. Any ideas? I've checked all connections and can't find anything loose. Thanks in advance.

Craig W

 

Could be the OMP. Is it coming from under/around the OMP directly?

 

Ok, I have a book for this thing, but it's in the garage and I'm headed to bed.
What's an OMP? I've checked the connections at the oil cooler, and the oil
pump. Plus the plastic lines that feed the engine. All seem to be tight.

Craig W

 

The plastic lines (4 of them) connect on the bottom to the OMP.

 

Ok, I figured that out. They all seemed to be tight. But the oil was a little
thicker in that area. Think it could be one of the lines? or the OMP itself?

Thanks

Craig W

 

The OMP itself has a tendency to leak. The lines can break, but usually it's pretty obvious when they do.

Try cleaning up the area right around the OMP and check back a few days later and see if that area is caked in oil.

 

I cleaned around it pretty well. But haven't been driving it. Pain to get that
'skidplate' or 'guard' whatever it's called on/off. It's off at the moment and
I have to go to work. I'll put it back together tonight and drive it a couple
of days. If it's the OMP, how much are they and how hard to replace??
Thanks for your help.

Craig W

 

There's a write up on here on how to rebuild them. It didn't seem to expensive. The write up is for S4's, but I'd say it will work with some adaptation for S5's (https://www.rx7club.com/2nd-generation-specific-1986-1992-17/rebuilding-my-s4-oil-metering-pump-521169/).

By "skidplate" or "guard" do you mean the big black plastic piece you put on the underside of the car? If so, you can run without it. I did for about a year because I didn't have one. However, make sure your cooling system is up to the job so you dont' overheat.