Oil Leak

[Virgil]

Shelby 427 FE aluminum block and heads. Recently completed rebuild. When sitting, there's a small continuous oil leak coming out from between the block and head at the very rear corner of block (#8 side.) Rolls down the edge of block, drips onto frame rail then floor.

Continuous meaning: Wipe up a small quarter size amount of oil today, dry off frame rail and block, tomorrow it will reappear without running the motor. Re-torqued the head bolts but no change.

Where's this oil coming from? Any correction suggestions?

Thank you,

Virgil

[patrickt]

Originally Posted by Virgil

Where's this oil coming from?l

It is probably coming from the bottom rear corner of your valve cover or from where the intake manifold mates at the corner. Here is how you can diagnose it, because an FE can leak invisibly. First, use some 409, Simple Green, or similar spray detergent along with a clean rag to clean where your valve covers meet your heads and the intake manifold is sealed. Clean it so that when you wipe a white paper towel along the back you get no marks of dirt or moisture. Take your car out and run it, then wipe a clean paper towel along the perimeter of the valve cover gasket. If you get any moisture mark at all then your valve cover gaskets are leaking. There are a variety of posts on how to deal with that or I can post a lengthy post with pics on how I dealt with mine. If your paper towel is bone dry then let the car sit for a day and look for the drops on the floor, then perform the paper towel test along the back of the intake manifold. If you get no moisture on your paper towel then go to the auto parts store and get a little oil dye test kit (see the pic below). You add the dye to the oil and then use a special flashlight and goggles to spot the oil leak. FE oil leaks along the back CAN be eliminated -- it just takes time and effort. Post your results and we'll take it from there. Last thought on Edit -- BTW, you can't rely on where you see the puddle on the floor as any indication on exactly where you are leaking from. An FE oil leak can literally be like an "ant trail" and go in small, almost imperceptible trails, and then drop from some totally unrelated place.

[Virgil]

Initial thoughts when leak was first discovered were exactly as you suspect. Unfortunately, it's not the common causes like valve cover gaskets or the seal between the intake manifold and the block and heads. Performed the white paper towel test numerous times v/c gaskets and i/m are sealed well and dry. It is originating from the corner I earlier described. And, it continues from that area even when the car is not run from day to day. Wipe down dry and perfect, car sits, next day oil is back without ever running the motor.

[patrickt]

Originally Posted by Virgil

Performed the white paper towel test numerous times v/c gaskets and i/m are sealed well and dry. It is originating from the corner I earlier described. And, it continues from that area even when the car is not run from day to day. Wipe down dry and perfect, car sits, next day oil is back without ever running the motor.

OK, I got my fluorescent dye kit from AutoZone for about $20. It came with the dye, a UV flashlight, and some goggles. Put that in your oil and it should show you exactly where your oil is originating. Until I did that, I was fooled a couple of times by very thin trails that would then accumulate in a different place that was totally unrelated to the real leak. I had drips that appeared to be coming directly from the transmission and one small leak that looked like it was brake fluid coming out of the box that holds my brake master cylinders... except, the drips glowed in the dark when I added the dye to my oil. That's your next step.

[Virgil]

Have used that product before ( not in this instance though) works very well. However, it will not change the location from where the oil is leaking from. The oil leak location is known, just uncertain what is the cause and how to correct it.

[ENTDOC]

I thought mine was coming from that area also but I finally found out it was indeed from the intake, head, block interface. I put RTV on it and it quit.

[Virgil]

Did your oil leak also continue leaking even when the motor wasn't run between the dry-offs and wipe downs?

[patrickt]

Originally Posted by Virgil

Did your oil leak also continue leaking even when the motor wasn't run between the dry-offs and wipe downs?

Yes, and like ENTDOC I was able to eliminate that one with a glob of black RTV on my finger that I swabbed in to the area.

[Bobcat]

I`ll go along with Patrickt and ENTDOC on the oil leak location ... had the same problem on my 427 S/O Galaxie and found it was coming from the intake/head interface at the angle where the intake meets the head on the rear of the engine. It would still show oil the next day after wiping down the night before . Like the others , a GOOD degreasing and then a smear/glob of RTV on the back of the juncture cured the problem . Good luck !

[thorconstr]

I had a leak at the point where the manifold valley and head meet. I tried different sealants (ultra black rtv, etc) and gasket combinations, to no avail. My nephew is a service manager for Toyota, he suggested a sealant they use for oil pans, camshaft housings, etc, without gaskets. I used Hitac on both sides of the head/manifold gasket ( as I had problems with that gasket being sucked into the intake port between the intake and water jacket port because of the narrow space with the stageIII head port job). I used the Toyota sealant in place of the valley gasket and up onto the lower edge of the head/manifold gasket. No more leaks. The Toyota part #00295-00103. Try it, the stuff is awsome. Make sure you let it cure for 24 hours before firing up and apply a thick layer (1/4"), you can trim off the excess after a couple of days.

[Virgil]

I don't think so. Since the last post, to quadruple check, went to auto parts store and bought another detector kit, added the dye and checked with the UV light. I-H-B interface dry, no other signs detected except from the subject location.

See pictures.

[patrickt]

Originally Posted by Virgil

I don't think so. Since the last post, to quadruple check, went to auto parts store and bought another detector kit, added the dye and checked with the UV light. I-H-B interface dry, no other signs detected except from the subject location.

See pictures.

Am I seeing that right that it looks like you have a leak directly under your #8 primary coming from between the head and the block and dribbling down the side of the block? With an obvious dribble at the rear corner but with what also looks like staining from oil leaking down the block directly below the primary as well?

[Virgil]

No I don't believe so. There is a raised area like a shelf in the block's casting at the location in question. I think it casts a dark shadow from the flash which appears to look like oil, but it is totally dry under #8.

[patrickt]

Originally Posted by Virgil

No I don't believe so. There is a raised area like a shelf in the block's casting at the location in question. I think it casts a dark shadow from the flash which appears to look like oil, but it is totally dry under #8.

OK, I ask that because I had a similar oil leak that was the result of a very small weep in a portion of the valve cover gasket directly above my primary #4. It looked just like what you photographed on your #8. The oil was easing down around the side of the head part that bolts to the primary and then apparently dribbling out of the bottom of the primary at the "six o'clock position." It then got in between the head and the block and travelled down towards the firewall before spilling out. It really looked like a head gasket leaking oil out of the side. It did all of that without making smoke as well. Any chance you can poke your camera in around the area and get some more higher resolution shots? I would really try and get a shot of any staining that is "above the head gasket" line. Here's a shot of my #4 leak when it finally tipped me off by staining the top of the portion of the head where the primary bolts. Note the obvious difference between #3 and #4 along with my red arrow pointing to the staining.

[Virgil]

Ran motor for about 10 minutes today. Will inspect those areas tomorrow. But now they are dry except for the back end. However, what you have described sounds very much like my symptom. Will possibly send picture with better resolution if something to show.

Thank you

[Virgil]

OK, rechecked motor the next day with UV light. Very very small amount of oil detected under i/h/b interface and down between head and block. Cleaned I-H-B joint throughly and resealed with a small glob of sealant. It's been a couple days, and have ran the motor once. Everyday so far it has been dry!!
The amount detected seemed much less than the volume of the actual leak. But the facts are irrefutable, it's dry!! Thank you guys for your assistance and persistence in helping solve this problem.

Virgil

[patrickt]

Originally Posted by Virgil

The amount detected seemed much less than the volume of the actual leak. But the facts are irrefutable, it's dry!!

Congrats, you'll get our bill in the morning. On the other hand, it's an FE, so it'll spring another leak somewhere else before too long.

[Virgil]

Spotted very very small amount of oil under I-B-H running down between block and head. Throughly cleaned and resealed with a glob of sealant at
I-B-H joint.

An ultra small amount of oil still shows under header #8 between block and head; but not enough to roll down block and off onto the floor. (Perhaps it just left over oil) Garage floor has been dry for 3-4 days.

Thank you guys for your assistance and persistence.

Virgil

[Virgil]

For some reason I did not see by first reply post. I assumed I erred some how and posted another. Sorry for confusion- it's still dry!!