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Oil Pan Sealing Problems - Big Block ???? What the Heck?

PurpleBeeper

PurpleBeeper

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70 Roadrunner 440 with a Milodon "hemi" pan & matching Milodon 1/2" oil pickup tube (I think this is a repro of a 71 hemi e-body pan), running stock windage tray. Old school Direct Connection chrome timing chain cover w/paper gasket & running cork oil pan gaskets. Hughes rear main seal cap w/silicone seal, cocked 1/16"-1/8" to one side & one drop of glue on ends w/silicone side seals. It looks like the oil is leaking out of the passenger side-rail area of the block/pan surface and "possibly" up by the timing cover. The oil leak is definitely more prominent on the passenger side as it sits now. This is a good size leak and I'm going through a quart of oil in 100 miles....1/2 quart in about 20 miles. I've got 7 quarts in the motor (6 quart pan + one quart for new filter being installed).

1. I've had a ton of oil leak issues on the bottom end since getting the motor back in this car (2-3 yrs).
2. Changed pan gaskets & rear main seal twice. Back of rear main seal was bone dry both times, so I'm pretty confident I don't have a rear main seal leak.
3. Since I have hardware store bolts in it, I thought maybe the pan bolts were bottoming out & I changed 1" bolts for 3/4" bolts.
4. I got lazy/frustrated and took it to a local shop. I gave them a brand new Milodon pan, cork Felpro gaskets, 7qts. oil/filter.

Guess what? Still bleeding oil all over the road in basically the same place. I'd over-torqued the OLD pan bolts and distorted the lip somewhat, but this is an identical NEW pan. The new pan came with a set of bolts and I believe they used most of the new ones. All I can think of is 1. Some bolts are still bottoming out...either I need 1/2" long bolts and/or there's a bunch of RTV or rust up in some of those holes.....so some bolts are still bottoming out and aren't really tight. 2. Somehow the cast iron on the bottom of the block is warped...and I didn't think that was possible. I'm so confused. Any/all ideas appreciated.
 
Check the bolt situation and the timing cover area.....
 
Get rid of those cork gaskets... those just bend panrails when the bolts are overtightened. Get a Superformance gasket and if the pan is bent, use Ultra Gray RTV.
 
moparnation74 said:
Check the bolt situation and the timing cover area.....
Click to expand...
I've looked at the timing cover area. I do see signs of them putting RTV in the corners where the pan meets the timing cover (as they should). I jacked the car way over towards the passenger side and I don't see any drips....it's already a 1/2 quart low on oil. I'm baffled.

The shop said it could be the timing cover sitting higher up and therefore not squeezing the timing cover/pan area enough to get a good squeeze on the gaskets. I guess that's possible since I did put a smaller cam in about 2 yrs. ago.
 
PurpleBeeper said:
I've looked at the timing cover area. I do see signs of them putting RTV in the corners where the pan meets the timing cover (as they should). I jacked the car way over towards the passenger side and I don't see any drips....it's already a 1/2 quart low on oil. I'm baffled.

The shop said it could be the timing cover sitting higher up and therefore not squeezing the timing cover/pan area enough to get a good squeeze on the gaskets. I guess that's possible since I did put a smaller cam in about 2 yrs. ago.
Click to expand...
If the two dowels are in the block and through the timing cover, that scenario is not possible...Hence is why Ma Mopar put those dowels in place......You may need a new timing cover.....but you would have to determine thats where it is coming from first..
 
moparnation74 said:
If the two dowels are in the block and through the timing cover, that scenario is not possible...Hence is why Ma Mopar put those dowels in place......You may need a new timing cover.....but you would have to determine thats where it is coming from first..
Click to expand...
That's what I was thinking. Shop guy said the dowel holes were "ovalled out" so I really need to look closer. Maybe if they are ovalled out I will change the timing cover (I have a clean/painted stock one) instead of another oil pan gasket.....pain in the butt though.
 
PurpleBeeper said:
That's what I was thinking. Shop guy said the dowel holes were "ovalled out" so I really need to look closer. Maybe if they are ovalled out I will change the timing cover (I have a clean/painted stock one) instead of another oil pan gasket.....pain in the butt though.
Click to expand...
If he realized that then did he bring that to your attention prior to installing everything?..........If not and mentions that to you after the fact is just wrong.....
 
First, order one of these... https://www.summitracing.com/parts/sum-g2339/overview/make/dodge

When you look at it you'll know it works..


Second if your losing a quart of oil every 100 miles either your driveway looks like the Exxon Valdez crashed into it and the bottom of your car is dripping oil or most of the oil is going somewhere else....

The common way for a big block Mopar to lose that much oil is through the intake valley pan... Sucked into the ports...

I strongly recommend a new valley pan sealed with Hondabond 4, it's not as hard as doing a pan gasket & I'll bet it helps..
 
I used a pair of the Superformance gaskets and my not-in-perfect-shape milodon pan has been bone dry. Small bead of ultra on both sides of both gaskets. CLEAN is the key, wearing latex gloves I used mineral spirits on all surfaces to scrub oily residue off. Then went over it again with denatured alcohol, to get the mineral spirit residue off. That got it squeaky dry and clean. Parts were lightly snugged, just enough to start squishing the sealer, then left to cure about 24 hrs, then tightened.
 
1 Wild R/T said:
The common way for a big block Mopar to lose that much oil is through the intake valley pan... Sucked into the ports...
Click to expand...
Oh boy...I hope you're not having intake issues again Beeper! You've been through enough of that. Good luck!
 
17C9EAD3-F00F-4101-B1BB-81ADDEBB1533.jpeg

I feel your pain, I went through this with a over restored Challenger a couple of years ago.
1st. Make sure your not building too much crank case pressure, have valve cover breathers on both sides.
2nd. Clean and degrease the engine again really good.
3rd. Order some tracerline dye and a uv flashlight.
4th. Get the car on a lift and add the dye to the motor oil and run the engine with the lights off in the shop. Rev it up some etc.
Now you will be able to see where the oil leak is really coming from without it blowing all over the place while driving.
I did the same routine of chasing the oil leak back and forth on the engine. Ended up being the rear main seal even though I had the engine builder put a new one in it. Third one did the trick.
 
PurpleBeeper said:
That's what I was thinking. Shop guy said the dowel holes were "ovalled out" so I really need to look closer. Maybe if they are ovalled out I will change the timing cover (I have a clean/painted stock one) instead of another oil pan gasket.....pain in the butt though.
Click to expand...


I chased this issue for years on my 383 Mag

I must have had the oil pan off and rear main seal a half dozen times

However

When the engine builder put the factory timing chain cover on back in the 90 s , the holes must have caught those dowel pins when he tightened down the bolts and pushed those areas outward on the cover

The pins where through the holes but but

It was plain as day when I pulled everything apart and put a metal straight edge on the timing chain cover flat sealing area

Those two areas where dimpled outward pretty bad , especially the passenger side hole

Smoothed everything out , cleaned up those two holes did not oval , just a simple clean by hand with the proper size drill bit

Still running the factory cover on my 383/432 Stroker now

Why I didn’t or never thought oil would travel like that is beyond me
 
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Original PCVs suck. Get a Wagner, stopped my engine from pushing oil out all over the place.

I don't think I've ever had a chrome part that didn't leak.

I think my pan gasket is cork, and it has to go. Bought a felpro but I might try that summit one.
 
PurpleBeeper said:
That's what I was thinking. Shop guy said the dowel holes were "ovalled out" so I really need to look closer. Maybe if they are ovalled out I will change the timing cover (I have a clean/painted stock one) instead of another oil pan gasket.....pain in the butt though.
Click to expand...


One more thing to add

Front seal

If those holes are ovaled out for whatever reason , and the timing chain cover was tightened down before the harmonic balancer was installed

Those dowel pin/holes keep the front seal aligned

Also



Fuel pump gasket and fuel pump rod threaded plug
 
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