I am looking for help on an oil leak I can't locate.

I have newly rebuilt engine with all new seals. I checked all the usual items, CAS, CAM SEALS, etc.

The leak is from the front ... looks like front main seal... and from weep hole in transmission.

I pulled the engine, removed oil pan, removed oil pump, and rear seal housing.

I put the engine back together with new front and rear crank seals, used the "Right Stuff" sealant on the oil pump, rear seal housing, and on the oil pan. I used new seals for the oil pan.

Put engine back in and the same thing! The engine is not broke in and the leak is bad enough I don't want to drive it.

Has anybody had this much problem?

The shop that put the block together is reputable. It has new pistons, rods, crank (FM 2.0 stroker kit) with new main bearing caps.

Any valuable help from experiance would be greatly appreciated.

 

Oil pump relief spring hole?

 

I will look at it but I never had it out. It is a new (non-mazda) oil pump. It has good oil pressure @ 60 psi cold and then drops to 30 when it warms up.

 

then it is not the relief valve

how much oil are we talking? I would put money on this:

one or both of your front camshaft seals are either missing, bad, or not in all the way. Reading comprehension fail
-and-

your CAS O-Ring is either missing or damaged Reading comprehension fail x2

Check these, should be a simple pull of the valve cover, report back.

Guess I'm out of ideas per my edits above. Do you have good oil-pan seals at both the front and the rear? I had a bad oil leak from a poorly installed rear oil pan seal.

 

If the OP relief spring is not there it just leaks oil back into the pan. I know from experience.

Did you used to have AC and then removed it and did not plug the bracket hole? That can cause oil to leak out the front.

 

I had a sneaky little bastard of a leak on my oil pan flange. I couldn't figure out why my driver's side motor mount was always wet and just assumed it was due to my compressor seal leaking down on it. It was using way too much oil and wasn't smoking though. It ended up being a leak on the pan flange where the recess is for the baffle is. The front edge was leaking where the baffle sits in the pan. It would only leak when it was running so it was hard to find.

Might be worth checking.

 

This is stupid but it does happen, has the car ever been jacked up by the oil pan? The oil pan might be cracked..... thats what the bastard that had my car before me did. I had a leak i couldnt figure out untill i pulled the motor to build it and inspected the oil pan.
Just a thought,
Mike

 

I cleaned the oil pan really good and no cracks were evident.

I retained the Air Conditioning and the bolt is there.

It leaks bad from under the ATI harmonic puller and on the edges were the pan meets the oil pump.

When I removed the pan and replace oil pan gaskets and front and rear seals I suspected that I had over-torqued the pan bolts. I bought in/lb torque wrench and am sure I did I did not overtighten bolts. I also used the Great Stuff sealer.

Well it looks like I will be pulling it for the third time!

Could the pan be warped?

Any ideas would be welcomed.

Thanks

 

Pull the front covers off, put it up on jackstands, clean it off and run it. Crawl underneath and watch.

 

agreed. keep us updated. My guess is front crank seal is a little crooked, or they just used rvt on the the oil pan and skipped out on the 2 partial gaskets.

 

I will keep you updated.

I installed the oil pan both times (heading for #three).

The first time I used black RTV with new front and rear partial gaskets and new front and rear crankshft seals. It leaked more in the front than in the rear.

The first time I suspected I torqued the pan bolts too much.

I was very meticulous the second time and again used new partial gaskets and new crank seals. I used the Great Stuff and carefully tightened pan bolts to 85 inch/pounds.

It is leaking worse this second time.

Getting good at pulling engine/transmission.

Anyone have a clean 1.8 oil pan for sale? My oil pan is from 95.

Cheers

 

You might have damaged your oilpan previously and not realized it.

Did you check to see if your crank is scored right where the seals are? I've seen that happen before and it will leak.

 

This may seem dumb and I'm not saying I didn't do this, but did you install the o-ring that goes between the oil pump and block? If say that would happen, you'd never see the leak at idle, but there would be oil everywhere down by the RMS. Also your cold Oil Pressure would be normal, but hot pressure would suck.

 

Have you thought about the valvecover gasket/sealant by the cam gears? It *could* leak down into the timing cover and out the bottom of the front.

 

I took the engine apart for the second time and was very careful to look for source of the leak.

I noticed after pulling the flywheel that the leak was above the rear main seal and the oil pan to block. Then I noted the oil passage plug. The plug looked tight but I suspected it due to the where the oil was.

When I removed the ATI damper and front covers I noted oil was above oil pump and below the water pump. Again I noted another oil passage plug.

With the oil pumped removed and the block on the engine stand, I used my shop air compressor to inject 60 PSI into the main oil pump outlet. I then noted oil leak out of the oil passage plug in the back of the engine.

So I ordered a new oil passage plug. When it arrived I carefully drilled a small pilot hole in the rear plug being careful to reduce (copper/brass) metal chips. When I went to larger bit needed to tap threads into plug the plug spun and removed very easily. I measured the old and new plugs with micrometer and the new one was at least .003 bigger in diameter.

After removing the rear oil passge plug I decided I must do the front one. The front one came out even easier withe just the small pilot drill bit.

Installed new oil passge plugs with Permatex #1 and they where both a tight press fit.

I have my fingers crossed, but suspect this IS the problem.

I suspect the machine shop that did the maching (new bores and line bore) didn't replace the oil passage plugs. The freeze plugs were obviosly replaced. I suspect when the block was hot tanked the oil passge plugs were loosened.

Anyway what a PIA for $10 in oil passge plugs.

Hope to have engine back in and ready to go shortly after Thanksgiving holiday. I will let you know for sure if this is it (pretty sure, but...?).

Happy Holiday!

 

Wow. I'm glad you found the problem.

I don't think hot tanking the block is going to make the plugs loose and I've never heard of a shop leaving the plugs in when hot tanking. It wouldn't drain and dry properly. Chances are that they simply used inappropriately sized plugs. Small assembly errors can lead to big PITA problems later.

 

I fixed it! Replaced both (front and rear) oil passage plugs. The engine doesn't leak a drop!

I put a hundred miles on it (following FMs break in suggestions) and changed the oil as suggested by Flyin Miata. Now I can't wait for a weather break to finish break in.

Anyway I am thrilled it is finally dry as a bone. Look for my engine build and experiances with it.

Cheers