what are signs of rear main seal leaking? - Forums at Modded Mustangs
 
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post #1 of 15 Old March 9th, 2008, 05:00 PM Thread Starter
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what are signs of rear main seal leaking?

i have an oil leak somewere from mid back on passenger side, n o oil on cats or anything above and cant see anything below with oil on it. my heater core is bad but the hoses arent leaking inside the engine bay, so i dont think its coming from that
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post #2 of 15 Old March 9th, 2008, 05:05 PM
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Check the back of the intake manifold and look at the top of the bellhousing. It is a common problem on these cars. Mine is doing it, i'm just waiting to get a different intake. For the rear main, you should have oil running down the exposed bottom of the block plate.
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post #3 of 15 Old March 9th, 2008, 06:28 PM
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Yeah, if you have oil running down the block plate it is usually the rear main. Sometimes it is the flywheel bolts not being sealed properly, sometimes the oil finds its way down from the top of the motor.

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post #4 of 15 Old March 9th, 2008, 07:11 PM Thread Starter
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so loose flywheel bolts can cause it? or will it leak becuase the bolts arent tight enough?
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post #5 of 15 Old March 9th, 2008, 08:00 PM
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the oil leak at the top behind the intake manifold, whats that all about, i think my cars got it

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post #6 of 15 Old March 9th, 2008, 08:56 PM
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the oil leak at the top behind the intake manifold, whats that all about, i think my cars got it
Just need to pull the intake manifold off. Put in new gaskets, and use rtv instead of the crappy cork gaskets on the front and back.
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post #7 of 15 Old March 9th, 2008, 09:04 PM
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yeah, those gaskets are worthless, use some of the Blue rtv and you will be set
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post #8 of 15 Old March 9th, 2008, 09:19 PM
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on my 89 aod car that i had you could jack it up and watch it run and once it warmed up you could see oil seep out from the back of the pan from the rear main seal, little hard to see but mine was pretty bad,
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post #9 of 15 Old March 9th, 2008, 09:49 PM
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so loose flywheel bolts can cause it? or will it leak becuase the bolts arent tight enough?
On some cranks the flywheel bolts intersect the oiling for the crank. So yeah you can get oil leaking out of the threads for the flywheel bolt if you don't use the correct sealer or teflon tape.

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04 Mach 1 12.7 @ 109 mostly stock - sold it
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post #10 of 15 Old March 10th, 2008, 01:08 AM
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Just need to pull the intake manifold off. Put in new gaskets, and use rtv instead of the crappy cork gaskets on the front and back.
That and also check your PCV valve, if it's popping out of up a little, it will spray on the firewall as well as I had the same thing happen and I replaced that. Also if you wish, I would highly recommend you pick up another "breather filter" for your pcv valve. It's actually located directly under the pcv valve grommet and is easy to take out. You can spray the hell out of it with carb cleaner and shake dry. It'll get clogged with gunk and shit and your breather can't breath, pushing manifold pressure though anywhere possible to exit

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post #11 of 15 Old March 10th, 2008, 11:59 AM
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^^^ +1, I usually take the oil screen out using a 4 inch dry wall screw. Then, holding it with a pair of vice grips, I burn all the crap off with a propane torch.

88 GT CHI headed 351w 10.8 @ 125 - still figuring it out.
03 Cobra 2.3 whipple 10.7 @ 129 - sold it
04 Mach 1 12.7 @ 109 mostly stock - sold it
89 LX procharged 302 515 hp 497 ftlbs 10.7 @130 mph - sold it

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post #12 of 15 Old March 10th, 2008, 12:31 PM
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I had what I thought was a rear main seal leak in my coupe. Pulled the aod when I was doing my aod-t5 swap and noticed it wasn't the seal, but the oil pan gasket. There was a slight/small break in the gasket and oil was getting through it.

Pulled the trans on my '93 f150 truck with a 302 and had the same problem with the oil pan gasket on it.

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post #13 of 15 Old March 10th, 2008, 02:22 PM
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AutoZone.com | Shopping | Parts | Product Detail - Oil Pan Gasket

Best oil pan gasket I've found yet.

Never fast enough.
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post #14 of 15 Old March 10th, 2008, 08:06 PM
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1 pc. felpro ftw! And re-usable too!
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post #15 of 15 Old March 10th, 2008, 08:12 PM
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That and also check your PCV valve, if it's popping out of up a little, it will spray on the firewall as well as I had the same thing happen and I replaced that. Also if you wish, I would highly recommend you pick up another "breather filter" for your pcv valve. It's actually located directly under the pcv valve grommet and is easy to take out. You can spray the hell out of it with carb cleaner and shake dry. It'll get clogged with gunk and shit and your breather can't breath, pushing manifold pressure though anywhere possible to exit
Yeah, you gotta let them breathe! The other night I get a call from a customer(SMU), a generator was in a pump room, w/ a 4b cummins. Customer said" My motor blew up and there's oil everywhere!". Drive out at 2 a.m., get there and there is oil from what seems like ceiling to the floor of this little room painted white. Look over, and the breather tube was folded up out of the way when one of our pm guys had changed the fuel filter! Blew the crankcase oil fill cap off and shutdown on low oil press.
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