Stubborn/elusive oil leaks-aluminum block
 

I had a great experience over the last several months chasing down oil leaks on my engine. As you all know, almost every oil leak on an FE-type block, or most blocks for that matter, eventually get to the rear and bottom of the bellhousing and mimick a rear main seal leak....or oil pan leak. My engine started leaking oil at about 5,000 mi. Before that, the only leaks had come from the valve covers, and I replaced them with the cork gaskets and no more leaks. However, the leaks started flowing and flowing big, like a pool 8 inches in diameter or so after a couple of hours of sitting when hot.

Not at first seeing any noticeable leaks from above, did some sub-frame checking with the flashlight and saw good doses of oil streaming down from the rear of the pan down the bellhousing cover, and even from the rear of the bellhousing where it mated to the transmission. On trips of more than a few miles, the oil would stream down mostly on the pass side frame rail, spray all over the rear trans mount, onto the rear crossmember, all over the 3rd member and onto the gas tank. A real mess.

So first order is to check torque on the pan bolts. OK, although the rubber gaskets look like they're pushing out a bit, so that may be a project for another day. Go for a run, no change. After clean up, thinking it may be coming from the rear of the intake manifold, since I do see a little fresh looking oil at the right rear, I decide after fretting for a couple of weeks, to pull the intake and re-seal. Pulled, checked fit, and everything seemed OK, but put in new steel sandwich intake gaskets and pure Right Stuff front and rear walls and at corners. Reinstalled everything, adjusted lifters, added fluids and went for a run. No change, still leaking. Newman!!

Told my friend Jim about it, he has a leak detector kit!!! So we get the kit, and put the dye in the oil. Sure nuff, more new oil coming down the back of the block from where it meets the oil pan. Nowhere else that I could detect with the blacklight. So now I'm really fretting, because I don't want to pull the engine to get to the rear main seal, which is the only other place I could think of. So I fret some more, and leave it alone for a few more weeks, cleaning the chassis and assorted parts after every trip, hoping it was going to go away. A total mess.

Then a few weeks ago, I had the car at the end of the driveway with the front wheels in the gutter, so the engine was angled just so the sun was directly beaming down to a very small area at the rear of the block just below on the right side where the intake manifold meets the head, AND THERE IT WAS. A little stream of dyed oil slowly seeping out of an oil galley plug with a hex slot in it.

http://www.clubcobra.com/photopost/d...de_Medium_.jpg

Due to its proximity to the side of the block, you couldn't openly see any oil flow down the side of the block to the rear bottom where it meets the bellhousing, even with the blacklight! I pulled the steel plug, teflon taped it up and reinstalled. Success!!! Stopped leaking. Story over? Not so fast.

A couple of weeks of pleasure driving go by, then I start seeing oil running down the driver's side frame rail, looking like it's coming from around the mechanical fuel pump or oil filter block area. NUTS!! I clean thoroughly and go for a run, then get under it and it looks like it's coming from the oil filter block and lines area. Tighten the bolts, but they're already tight. Then I see IT!!! Another oil galley plug, just above the fuel pump. It looks like it has a little fresh oil on the block area around it, which could be dripping down onto the fuel pump and oil block area. It's the little white area in the picture below above the fuel pump.

http://www.clubcobra.com/photopost/d...mp_Medium_.jpg

Same kind of plug with pipe threads like the last one. So I pull my coil to get to it, and apply the teflon tape, and SUCCESS again. No more leaks.

And just for good measure, I pulled the other accessible plug just above the starter and sealed it as well.

http://www.clubcobra.com/photopost/d...ck_Medium_.jpg

Now there are at least two, maybe three more plugs at the rear of the block just ahead of the flywheel, but for the same reason I didn't want to change the rear main seal, those will have to wait, but they don't seem to be leaking now.

I think these plugs started leaking due to various heat/shrink cycles on dissimilar metals owing to more and more hours on the engine. And a gap finally formed. Just wanted to share, so what appears to be something really big, may only be something easily fixed at the end of the day. Nice!!

Tom, I can't remember what kind of block that you have. Is it a Pond, Genesis or CSX?

Nice job on hunting down the leaks. I've chased a few leaks on a BBC for my Vette and actually pulled the engine, took it to a dyno and used a UV leak detector kit. What a PITA.

I'm very thankful and happy that my FE has decided to give me a break. Knock on wood.

[quote=RodKnock;958804]Tom, I can't remember what kind of block that you have. Is it a Pond, Genesis or CSX?QUOTE]

It's a fairly early CSX block. No. 381. I don't think production date is the issue. I'm convinced now that it's a matter of heating and cooling cycles involving steel vs. aluminum, over time. The plugs were in there with no sealant on them. So I think it's only a matter of time for a joining of dissimilar metals to eventually move. LIke I said, no leaks until around 5,000 mi. Then it hit, and at slightly different times.

Tom

you might use aluminum plugs if you have any more troubles.

Find a shop with a smoke tester... must faster for finding those pesky leaks that aren't obvious.

Now you tell me. I hope I don't have to go there again. I think I've gone over just about every opening there is externally, again without taking the bellhousing off. But that's a whole other world isn't it. I wanted to post this so if anyone else has this experience it may help them to eliminate possible causes earlier. I'll check into the smoke test, thanks.

My Genesis iron blocked leaked from the same places as yours.
There was a thread posted a couple weeks about about the smoke tester. I talked to my brother who works for a car dealership and he said it is by far the easiest way to track them down.

While your enjoying you 'cavity search' :)-
I had a thread a few weeks ago about pan sealing tips from engine builders and got a lot of help. It's in the FE forum.
Barry helped me identify that the source of the oil was the oil pressure relief valve at the drivers rear of the block, just above the pan rail. It drains constantly hot or cold. Coupled with a pan rail that was not flat and poor gasket/silicone/fasteners technique was the reason for my pain.
All better now.
See here:
http://www.clubcobra.com/forums/fe-talk/96713-engine-builders-favorite-oil-pan-sealing-tips.html

Chas, I recall seeing your thread, but since I don't seem to have leaks from the pan, I'm going to leave it alone. If I do have to remove it, then I'll follow your lead. I was curious to know if the pan can come off and clear that rear crossmember on a CSX car without lifting up the engine, while still clearing the crank counterweights. I'm assuming an ERA is pretty much the same as mine. I'll have to wait until I need to do that job to find out.

Tom, was no sealant originally applied because of the dissimilar metals and the fear that different expansion rates may result in a crack to the block? Or did the builder simply miss this step and fail to apply any sealer to the plugs?!?

-Dean

Dad,
Not giving you any advice, just merely offering the information of the helpful guys that answered my thread. Hope it helps you too.
No, the ERA rectangular tube chassis has no crossmember under the pan-which was the only saving grace about my toil. The CSX has the round tube ladder style chassis and apparently the crossmember may interfere with pan removal. Hope a CSX guy chimes in about clearance.
Better yet, I hope your pan seal is not part of the problem.:)

Chase the threads with a tap, clean with carb spray, then PST or better yet blue loctite.

Never had a problem with loctite'ed galley plugs.;)

Dean,
Engine built by Keith Craft, but I can't say who put the plugs in. They're chrome plated, except for the one by the starter, and made of steel. They were absolutely clean and without trace of any sealant. So who's to know? All I know now is that they're sealed and there are no more leaks whatsoever from the engine and all is clean. I can't believe it. For now.

Tom