Oil Pan Leak - Crankcase Pressure

[robl72]

I have a newly rebuilt 440 RB stroked out to 496. Runs great but it has a persistent oil pan leak at the rear of the pan. I am running a stock 402 pan with windage tray and have tried every gasket available (currently running Moroso Silicone with Steal core) and even used silicone sealant. It holds for a couple of heat cycles but eventually starts to leak at the rear of the pan after 4-5 trips. Also had leaks at the valve covers and Fuel pump but stopped them using Silicone Gaskets and silicone sealant. Could this leak be the result of too much crankcase pressure? I have tested the PCV Valve and it seems fine. No Idea what to do.

 

[khryslerkid]

Are you sure it's not coming from the main rear seal?

Beautiful engine compartment!

 

[bm02tj]

Do you have many miles on motor and are the rings seated
You may need to go out and put some good miles and seat rings then reseal pan

 

[coloradodave]

Really nice job on the engine compartment. There are many, many posts on here dealing with oil leaks from the rear of the motor so I won't re-iterate. Good luck.

 

[robl72]

I am not thinking it is the rear main because it seems to seal for the first 3 or 4 heat cycles after doing a new gasket job. After that like clock work it starts to seep through then leak. Engine has at least 800 miles on it so I assume the rings are seated. Did the last gasket job recently. (Have used three different types of gaskets with Ultra Black Sealant, 1. Fel-Pro Steel core twice, 2. Mopar performance and now 3. Moroso silicone/Steel core).

Thanks for the replies guys. Any info helps so please re-iterate if you would like to.

 

[khryslerkid]

That makes sense, about the heat cycles.

Now my personal opinion about silicone sealant is that the only thing that it is good for is a leaky rain gutter! The automotive silicone sealant was designed for use on a cover with no gasket. Not with a gasket.

I would use a cork gasket with "Coppercoat" spray on both sides. Let it set up a couple of minutes before attaching. Tighten your pan bolts untill you see the cork gasket just starting to move at each bolt.

In you corners where the rubber meets the cork,*use "Permatex" #2 to seal the joint.

The rubber seal should be installed clean and dry. Maybe a light coat of coppercoat spray to hold in place for assembly.

MHO, I hate silicone sealant! Nothing but problems...

Good luck.

 

[miller]

Yeah! What he said!
(Glad I'm not the only one.)

 

[robl72]

OK makes sense about the sealant. What are your thoughts about too much crankcase pressure. Could this be a contributor and does having a high volume oil pump have anything to do with it?

 

[MarPar]

Rob, I have been fighting leaks with my motor (V/C's and oil pan) for 4+ years now and it has been driving me nuts!!

then one day I thought summabitch, could it be too much crankcase pressure??

Not too long ago, I changed out my (I guess what you would call a PCV) on the drivers V/C from what you have to a K&N open element filter, and 3/4's of my leaks are gone (I still have the actual PCV from carb to pass side V/C hooked up). I re-did my V/C's and I dont get that "smell" anymore...you know, that oil burning on exhaust/manifold smell. the oil pan is still leaking, but that will re-done in a couple weeks.

I aint no "real" mechanic, but sheeit that drastic of a change can't be a fluke....

 

[coloradodave]

Oil pump has nothing to do with it. If you have too much crankcase pressure it would be from compression going past the rings and you would generally see blow-by out the driver's side breather on your motor (in your case, inside the air filter housing). Best way to diagnose that is with a leak down tester. I agree with the others on using silicone WITH gaskets. One or the other. I have had great results with Jeg's windage tray that is reusable and has double rubber seals on both sides. Or, like was said, a cork gasket with coppercoat or gask-a-cinch works as well.

 

[MarPar]

Oil pump has nothing to do with it. If you have too much crankcase pressure it would be from compression going past the rings and you would generally see blow-by out the driver's side breather on your motor (that is a vented breather, right?) Best way to diagnose that is with a leak down tester. I agree with the others on using silicone WITH gaskets. One or the other. I have had great results with Jeg's windage tray that is reusable and has double rubber seals on both sides. Or, like was said, a cork gasket with coppercoat or gask-a-cinch works as well.

So Dave, if compression is getting past the rings, that means the rings are going bad, right?

 

[robl72]

I found out the Jegs windage tray a day after I put on my current Moroso gaskets. I have heard good things about them and that is definitely my next step although at this point I feel like it will never seal......(just my frustration talking). Do you use any sealer with the Jegs Tray or just dry?

 

[coloradodave]

Compression can get by the rings several ways. Rings that haven't seated (incorrect oil or break-in procedure), rings incorrectly installed (upside down, end gaps too small, too large or not staggered), or, of course, rings broken on installation. Again, a leak down test will show the condition of each component in the cylinder and normally, if you pull the driver's side valve cover breather off, you would see blow-by. If indeed, your motor runs "great", like you said, I doubt pressure is your problem. You could also put two open breathers on the covers as a test.

As far as the Jeg's set-up, I installed mine dry. Since you're not trying to juggle two gaskets, a windage tray and the pan all at once, it's no problem. Make sure the pan rails are dead flat and don't over tighten the bolts.
Good luck...

 

[superbeedave]

This sounds like what I had 4-10 years ago. I had a leak at the front right corner on my oil pan for a lone while. I replaced oil pan gaskets 5 or 6 times. One new oil pan, one new windage tray and different sealants and it would still leak after 15 to 20 mins. of driving until I had the engine rebuilt 4 years ago. I told my builder to focus on that area due to I had an oil leak at that point. He magnafluxed it and said there was no leak but he did say on the inside of the block at the bolt hole there was porosity. He applied considerate amounts of JB weld on that area and 4 years later still no leak!
I realized that at some point I replaced the stock oil pan bolts with stainless and they were probably a few threads to long and it may have broken thru the hole. So if your leak is coming from a bolt hole you will not be able to seal it up unless you seal it from the inside of the block. Good luck!

 

[khryslerkid]

Crankcase pressure.

I worked with a crew that was running a 500 in. alcohol, Super Comp. and if we lost the seal under the distributor, it would blow oil everywhere. Took a few tries before we found the right seal. Now that seamed to be a lot of crankcase pressure.
The thing was, this engine had valve covers equipped with hoses that dumped into the header/mufflers to prevent too much pressure. That was what I was told. I think they helped with the amount of moisture that will accumulate in an alki engine.

So is there such a thing as crankcase pressure that's capable of blowing gaskets? Could you makeshift a gauge to mount on a valve cover inlet to check such a thing?

 

[MarPar]

Crankcase pressure.

I worked with a crew that was running a 500 in. alcohol, Super Comp. and if we lost the seal under the distributor, it would blow oil everywhere. Took a few tries before we found the right seal. Now that seamed to be a lot of crankcase pressure.
The thing was, this engine had valve covers equipped with hoses that dumped into the header/mufflers to prevent too much pressure.

That is called a "crankcase evac" system, right Kid? and it still blew oil everywhere?? Yikes!!

what all did you use to finally seal the dizzy hole? {if ya don't mind me askin'}

 

[khryslerkid]

Chankcase Evacuation is what I've always known it as...

It was a Mallory distributor and had an o- ring or a flat gasket. Don't remember but used a neoprene material replacement, I do remember. The owner kept trying all kinds of remedies, even smearing silicone all around it. (Man I hate short cuts) But the right part is always the right way to go. (BB Chevy) I could tell you stories about that car all day.

Had to have been an o-ring.

 

[68gtx]

have you tried "the right stuff"? its a black silicone that even sticks to oily surfaces, I have used it for years . everywhere and had great success, with gaskets and as a gaskets

 

[440+6]

I used the Jegs gasket/windage tray when I replaced my oil pan last winter, great product easy to install under a car and so far no leaks.