Well It Leaks AGAIN!

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superchargeddrt said:
Well,
The rear main seal leak on the Dart gas returned. I am beyond frustrated. I have had this engine out 3 times already. I put the Superformance seal in and it worked great for several months but now the leak has returned and I had to have the Dart flatbeded home. I am currently in Larry's truck heading to Carlisle, I'll have fun but it's just not the same without your car Larry's brother Bob thinks it could be the fact that the Dart runs at 70 PSI at highway speeds and the high pressure coupled with the temperature caused the main seal to fail. He thinks I should go with a stock pump, what do you guys think?
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What oil pan do you have?
Windage tray?
Sump level too high at highway speeds?
I had a daily driver that leaked at the rear seal, real bad. Took a quart of oil out it and it dried up in a week.
 
Rear main seals never see pressure from the oil pump, neither do oil pan seals, so running the oil pump maybe useless.
And if the issue is due to a surface finish or diameter issue at the rear main seal crank interface, you may not see anything with the crank static.
Not saying that I would not do what you are doing, just saying don’t be surprised if you do not duplicate the leak in bench testing.
 
my68barracuda said:
Rear main seals never see pressure from the oil pump, neither do oil pan seals, so running the oil pump maybe useless.
And if the issue is due to a surface finish or diameter issue at the rear main seal crank interface, you may not see anything with the crank static.
Not saying that I would not do what you are doing, just saying don’t be surprised if you do not duplicate the leak in bench testing.
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Mine is a side seal problem----------
 
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Ok,
So the engine is out and on the stand. It looks like oil was spraying all over the rear of the engine. We ran the oil pump with a drill and the seal was leaking heavily from the lower side. I will take a video of this when I get home on Friday.
 
superchargeddrt said:
View attachment 1715381365 View attachment 1715381367 View attachment 1715381365 View attachment 1715381366 View attachment 1715381367 Ok,
So the engine is out and on the stand. It looks like oil was spraying all over the rear of the engine. We ran the oil pump with a drill and the seal was leaking heavily from the lower side. I will take a video of this when I get home on Friday.
Click to expand...

With the converter whipping around, I'm not surprised it's blowing oil everywhere.

One little leak can make a huge mess, on top of being a giant PITA.
 
Oil will flow out both sides of the rear main bearing, front and rear. On the rear side, towards the seal, there is a very obvious drain in the main cap that allows this oil flow down into the pan and not build up any pressure behind the seal.
  • This drain could be blocked/missing
  • Or the seal is so messed up that oil shooting right past from the bearing area and out.
  • Or a slight bit of clearance exists between the pump flange and the cap; enough oil is shooting out there and getting past the pan gasket, but not enough to drastically drop the oil pressure.
  • Or a slight clearance or unevenness exists between the cap and block where the pressurized oil flows into the block and it is escaping there
I'd pull the flexplate now and run the pump to see better where the oil is getting out so you can better diagnose this. Any investigation that can help needs to be done; you've been through this long enough!
 
Not that this is the problem, but I recall a member trying to install an expansion plug up above the rear main and it cracked his block. I believe he found it was the wrong size plug.
 
nm9stheham said:
Oil will flow out both sides of the rear main bearing, front and rear. On the rear side, towards the seal, there is a very obvious drain in the main cap that allows this oil flow down into the pan and not build up any pressure behind the seal.
  • This drain could be blocked/missing
  • Or the seal is so messed up that oil shooting right past from the bearing area and out.
  • Or a slight bit of clearance exists between the pump flange and the cap; enough oil is shooting out there and getting past the pan gasket, but not enough to drastically drop the oil pressure.
  • Or a slight clearance or unevenness exists between the cap and block where the pressurized oil flows into the block and it is escaping there
I'd pull the flexplate now and run the pump to see better where the oil is getting out so you can better diagnose this. Any investigation that can help needs to be done; you've been through this long enough!
Click to expand...
All good things to check and I will do that. I will post a video of the leak on Friday when I get home. Thanks for your input.
 
Daves69 said:
Not that this is the problem, but I recall a member trying to install an expansion plug up above the rear main and it cracked his block. I believe he found it was the wrong size plug.
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I sure hope that's not the case but I will look. My machinist put in the plugs so if he cracked the block I would TRY to go back to him. Thanks for the advice.
 
Daves69 said:
Not that this is the problem, but I recall a member trying to install an expansion plug up above the rear main and it cracked his block. I believe he found it was the wrong size plug.
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Now that you mention it, those look like an odd collection of staking marks around the periphery of the cam plug. OP, can you read the PN on that cam plug, just to check it is correct?
 
nm9stheham said:
Now that you mention it, those look like an odd collection of staking marks around the periphery of the cam plug. OP, can you read the PN on that cam plug, just to check it is correct?
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I will when I get back home. I am a Field Service Engineer and I am in Myrtle Beach SC right now working. I will see if I can get the PN
 
Pull that cam plug out.
Get cup style ..fine line of sealer then install cup face toward cam and using a punch...hammer it in the center to spread and lock it into place...then another clean bead of sealer around plug edge to make sure its leak proof.
 
Also there are two variants of the cam plug.
One has a flange and one does not.
Use the type your block had originally.
 
sireland67 said:
Also there are two variants of the cam plug.
One has a flange and one does not.
Use the type your block had originally.
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Already pointed out.
I'm referring to the other style, the cup.
I bet his builder pushed that std style one out on accident when the cam went too far back.. so he popped it back in and siliconed it.
 
Yes the cup style is what I have seen in every small block.
I have never tore one apart with the flange style in it.
 
I hear you, it would be easier to replace the balancer on the supercharged engine, and been done with it.
 
When he cracked the block did he notice it right away Dave?
Daves69 said:
Not that this is the problem, but I recall a member trying to install an expansion plug up above the rear main and it cracked his block. I believe he found it was the wrong size plug.
Click to expand...

Supercharged I commend your persistence! Man what a frustrating journey for you. Hoping this is it!
I wonder when you install new plug if you should pull cam 1st so you dont risk hitting it? Just a thought, fingers crossed.
 
4spdragtop said:
When he cracked the block did he notice it right away Dave?


Supercharged I commend your persistence! Man what a frustrating journey for you. Hoping this is it!
I wonder when you install new plug if you should pull cam 1st so you dont risk hitting it? Just a thought, fingers crossed.
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Thanks,we will be careful when we replace the seal and, if necessary the plug.
 
The bottom looks pushed in, could be in there crooked ?
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Good eye..... might go along with what looks like the lower lip appearing to be raised up. Sure looks crappy. Musta been the new kid in the shop who did this one!
 
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