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383 rear main bearing seal leak? #1883592
08/02/15 04:09 PM
08/02/15 04:09 PM
Joined: Feb 2012
Posts: 137
midwest - USA
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69/70 Plymies Offline OP
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midwest - USA
Presently have 1,000 miles on a '70 383 basically stock rebuild. Installed the billet rear main seal retainer from Mancini Racing P/N MRE-223 with the belief that was pretty sure way to stop leaks in this area. Yesterday, I was under the car checking the clutch adjustment. There was a light film of oil on the inside surface of the bellhousing and a "partial" drop of oil hanging on the bottom of the flywheel mounting plate.(The clutch is good and dry). A Mopar friend uses a STP-like oil additive to help combat oil leaks. Is this a good idea to try? Any other opinions on how to identify and fix this oil leak problem is greatly appreciated.

Re: 383 rear main bearing seal leak? [Re: 69/70 Plymies] #1883604
08/02/15 04:31 PM
08/02/15 04:31 PM
Joined: Jan 2003
Posts: 32,985
Grand Prairie,Texas
stumpy Offline
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stumpy  Offline
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Grand Prairie,Texas
Recheck the pan bolt tightness.

Re: 383 rear main bearing seal leak? [Re: stumpy] #1883759
08/02/15 08:34 PM
08/02/15 08:34 PM
Joined: Feb 2012
Posts: 137
midwest - USA
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69/70 Plymies Offline OP
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Originally Posted By stumpy
Recheck the pan bolt tightness.


Can oil leaking from the oil pan find it's way into the clutch/flywheel dust cover and then up onto flywheel mounting plate, but NOT on the flywheel to clutch surfaces?

Re: 383 rear main bearing seal leak? [Re: 69/70 Plymies] #1883820
08/02/15 10:02 PM
08/02/15 10:02 PM
Joined: Jan 2003
Posts: 32,985
Grand Prairie,Texas
stumpy Offline
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Yes it can. Oil can find it's way anywhere. Also take a look at the oil pressure sending unit. If it leaks oil will run down the rear of the engine.

Re: 383 rear main bearing seal leak? [Re: 69/70 Plymies] #1884064
08/03/15 02:37 AM
08/03/15 02:37 AM
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
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RapidRobert Offline
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Lincoln Nebraska
Quote:
A Mopar friend uses a STP-like oil additive to help combat oil leaks. Is this a good idea to try?
I would suggest no for that & instead open it up/fix it. Not fun but no other way


live every 24 hour block of time like it's your last day on earth
Re: 383 rear main bearing seal leak? [Re: 69/70 Plymies] #1884068
08/03/15 02:44 AM
08/03/15 02:44 AM
Joined: Aug 2003
Posts: 43,305
Bend,OR USA
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Cab_Burge Offline
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Bend,OR USA
Try to find out exactly where the oil is coming from scope The oil leaking from the rear main seal will possibly be on the front of the clutch inspection cover and definetly on the front of the flywheel slung out into the bellhousing scope I've seen valve cover leaks and oil leaking from the back of the intake valley pan make some guys thing they had a rear main seal leaking, lots of gremlins out there on new builds shruggyHopefuy it is not leaking from the cam plug in the rear of the motor above the crankshaft luck Good luck up Let us know what you find and do to fix it.

Last edited by Cab_Burge; 08/03/15 02:46 AM.

Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: 383 rear main bearing seal leak? [Re: 69/70 Plymies] #1884091
08/03/15 06:02 AM
08/03/15 06:02 AM
Joined: Jul 2013
Posts: 1,272
Northern Calyfornua
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Sxrxrnr Offline
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Sxrxrnr  Offline
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Northern Calyfornua
Do a search of the forum for rear main seal leaks. Many threads on the topic and ideas how to deal with.







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