350 rear main

[19gmc84]

Oil pan gasket? Oil sending sensor up top ? Rear intake manifold leak although that should just be a little dribble.

This engine although not new...we put in just recently...engine was powerwashed and painted before we put in so any oil leak should be noticeable...I've checked all over the engine...no oil pan gasket leak before and new one was put in after main seal replacement, oil sending sensor should be up by distributor right? No oil there...don't see any coming from manifold either...or valve gaskets, could be missing it...but don't think so.

So anyway...maybe it's starting to seal it self up...after driving it a few times...I see oil...but dipstick shows I've lost just a tad bit of oil...maybe the oil spreading is making it look worse than it really? I was told I had to drive it and it would hopefully start sealing up...is this true? I expected it to leak a little anyway...just because the two piece is crappy design, was just hoping it wouldn't leak as bad.

 

[MadOgre]

Its very hard to see the oil sender leaking. It runs down the back of the block to either side and then down and into you inspection cover. If you have ever put a wrench on the sender it self to tighten it, it is probably leaking. Always tighten from the fitting not the body of the sender.

The leaking by the starter would suggest this or a leaky manifold is the problem.

As far as breaking in the seal you really shouldn't have that problem. Maybe on your first drive you have to add a bit but that should be it.

 

[chengny]

Did you do this?

Note: image does not show the seal in the offset position as decribed below. If it did, the left hand side of the seal would be recessed into the cap and the right hand side would be exposed a similar amount (or vice-versa, it doesn't matter which way it's offset):


Offset the seal 3/8″ from flush with the block. In other words, one side will be sticking 3/8″ out of the block and the other side will be 3/8″ inside the block. Fel-Pro states that not doing this is one cause for leaks after install.

Also, apply a light coat of sealant to the block/bearing cap interface and the seal seams.

You must be registered for see images attach

 

[DoubleDingo]

Did you do this?

Offset the seal 3/8″ from flush with the block. In other words, one side will be sticking 3/8″ out of the block and the other side will be 3/8″ inside the block. Fel-Pro states that not doing this is one cause for leaks after install.

Also, apply a light coat of sealant to the block/bearing cap interface and the seal seams. Note - this image does not show the seal in the offset position as decribed above. If it did, the left hand side of the seal would be recessed into the cap and the right hand side would be exposed a similar amount (or vice-versa, it doesn't matter which way it's offset):

You must be registered for see images attach

That is exactly how I did mine when I did it. I used a Victor Reinz gasket and Permatex Ultra Black as you stated by putting some, about the size of a pea, between the block and cap, but I also added a tiny dab, just enough to make a thin film on the ends of the seal, too, to help glue the ends together.

 

[MadOgre]

That is exactly how I did mine when I did it. I used a Victor Reinz gasket and Permatex Ultra Black as you stated by putting some, about the size of a pea, between the block and cap, but I also added a tiny dab, just enough to make a thin film on the ends of the seal, too, to help glue the ends together.

Ya but did you off set the seal so where the bearing cap meets the block is not where the 2 seal halves also meet. This would potentially allow an easy route for oil to escape. Also having the seal halves meet inside the seal track allows for a better end seal.

I still think if you start feeling around with your hand up top at the back of your block you will find oil leaking from either the manifold end seal or the oil sender. You wont be able to see either leaking in these old squares unless you feel for it.

 

[MadOgre]

Did you do this?

Offset the seal 3/8″ from flush with the block. In other words, one side will be sticking 3/8″ out of the block and the other side will be 3/8″ inside the block. Fel-Pro states that not doing this is one cause for leaks after install.

Also, apply a light coat of sealant to the block/bearing cap interface and the seal seams. Note - this image does not show the seal in the offset position as decribed above. If it did, the left hand side of the seal would be recessed into the cap and the right hand side would be exposed a similar amount (or vice-versa, it doesn't matter which way it's offset):

You must be registered for see images attach

Ya so basically the picture is an example of how not to do it.

 

[chengny]

Ya so basically the picture is an example of how not to do it.


Ha ha ha. MadO, you f*ckin ***** - that is the funniest thing I've seen/read in a long time.

Almost made me spit my beer out.

 

[MadOgre]

Ya so basically the picture is an example of how not to do it.


Ha ha ha. MadO, you f*ckin ***** - that is the funniest thing I've seen/read in a long time.

Almost made me spit my beer out.

I cant help it! I was born this way lol

 

[SkinnyG]

Some say offset the seals, so the seam of the seal is not aligned with the seam between the block and cap.

Some say do not offset the seals, since the seal is a crush fit and it will seal better if the seal seam is aligned with the seam between the block and cap.

Some say put some sealer on the ends of the seal itself.

Some say never put sealer on the ends of the seal itself.

All say put some sealer on the cap mating surface.

Some specify putting some sealer in the chamfer on the cap so oil doesn't seep through there.

In the immortal words of Agent Mulder "The truth is out there...."

 

[DoubleDingo]

Ya but did you off set the seal so where the bearing cap meets the block is not where the 2 seal halves also meet. This would potentially allow an easy route for oil to escape. Also having the seal halves meet inside the seal track allows for a better end seal.

I still think if you start feeling around with your hand up top at the back of your block you will find oil leaking from either the manifold end seal or the oil sender. You wont be able to see either leaking in these old squares unless you feel for it.

Offset the seals, added a pea sized dab off ultra black outside of each piece standing proud of the block and cap, and put a thin film of ultra black on the ends of each end of the seal.

 

[firebane]

Offset the seals, added a pea sized dab off ultra black outside of each piece standing proud of the block and cap, and put a thin film of ultra black on the ends of each end of the seal.

RTV won't stick properly to the seals that is why they are a dry fit type seal Same as oil pan gaskets and such.

 

[DoubleDingo]

RTV won't stick properly to the seals that is why they are a dry fit type seal Same as oil pan gaskets and such.

Well crap! Oh well, I guess I will rock it until I see a leak develop back there.