rear main seal leaking?
Thread Starter
Instructor
Joined: Jun 2001
Posts: 188
Likes: 0
From: nova scotia canada
rear main seal leaking?
Have had a small but annoying oil leak for the last 2 years. Had my machanic booked to install
the rear main but after removing the oil pan and inspecting the area directly under the seal
decided not to change it.We checked the area with a trouble light and everything looked so
dry we decided not to go ahead.The leaking oil was running down the face of the flywheel
inspection plate,collecting on the bottom of the plate then dripping on my garage floor.I still
have the leak and no answers,should we have changed the seal anyways?Any other place the oil
could be coming from?New rebuild,2500 miles.
help please
thanx wade
the rear main but after removing the oil pan and inspecting the area directly under the seal
decided not to change it.We checked the area with a trouble light and everything looked so
dry we decided not to go ahead.The leaking oil was running down the face of the flywheel
inspection plate,collecting on the bottom of the plate then dripping on my garage floor.I still
have the leak and no answers,should we have changed the seal anyways?Any other place the oil
could be coming from?New rebuild,2500 miles.
help please
thanx wade
Race Director
Joined: Dec 1999
Posts: 16,945
Likes: 9
Re: rear main seal leaking? (wadey)
Year of car???
If you have an oil pressure sender next to the distribuer, they tend to leak at the crimped flange. Or take a look at the rear manifold seal, they are common leakers, replace with thick line of silicon, do not use the rubber gaskets
Marck
[Modified by Twinnie, 3:53 AM 6/26/2002]
If you have an oil pressure sender next to the distribuer, they tend to leak at the crimped flange. Or take a look at the rear manifold seal, they are common leakers, replace with thick line of silicon, do not use the rubber gaskets
Marck
[Modified by Twinnie, 3:53 AM 6/26/2002]
Race Director
Joined: Mar 2001
Posts: 11,322
Likes: 1
From: Living in the Hartland
Re: rear main seal leaking? (Twinnie)
Or take a look at the rear manifold seal, they are common leakers, replace with thick line of silicon, do not use the rubber gaskets
Just curious
BTW I keep using them with a line of sealer above and below them with no problems.
Race Director
Joined: Dec 1999
Posts: 16,945
Likes: 9
Re: rear main seal leaking? (Fevre)
The old ones had small holes in the block and the seals had little bumps. Those held up pretty good.
I think they keep making them to stuff in the gasket kits & charge money.
Marck
I think they keep making them to stuff in the gasket kits & charge money.
Marck
Melting Slicks
Joined: Jul 1999
Posts: 3,030
Likes: 17
From: White Pine / Dandridge TN
Re: rear main seal leaking? (wadey)
I replaced my rear main seal and still have the exact oil leak you describe. I had replaced my intake several years ago, but I think the leak is coming from the rear of the intake. I have already added teflon tape to the oil pressure sender to seal it. You can purchase an ultraviolet additive to your oil. Then you use a blacklight to find the leak. I'm really thinking of doing this before I start taking apart anything else. I hate making extra work for myself but really want this oil leak gone!
Regards,
Jim
Regards,
Jim
Team Owner
Joined: Aug 1999
Posts: 30,995
Likes: 99
From: Ontario
Re: rear main seal leaking? (Jim73)
Jim is bang on. Use this dye and observe the leaks with a UV/black light to see exactly where they are coming from. Cost is about $4.00.
*Edit*-Oops, here is the pic.
[Modified by paul79, 6:31 PM 6/26/2002]
*Edit*-Oops, here is the pic.
[Modified by paul79, 6:31 PM 6/26/2002]
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Melting Slicks
Joined: Feb 1999
Posts: 2,473
Likes: 10
From: New Paltz, New York USA
Re: rear main seal leaking? (paul79)
Paul79, Can you tell me where you got the tracer dye from. It's a great idea. I have a ton of oil leaks and I would like to try and find some of them. Thanks.
Burning Brakes
Joined: Mar 2002
Posts: 803
Likes: 0
From: South San Francisco CA
Re: rear main seal leaking? (wadey)
My rear main seal has been leaking since 1970...when I got the car. It's a 50 cent piece size puddle after two weeks and really no big deal. I've thought about fixing it, but there is really no guarantee the new one won't leak more. I've left well enough alone for 30 years and the extra oil is insignificant. Sometimes cars just leak...it's inevitable....especially with the older technology.
Pro
Joined: May 1999
Posts: 749
Likes: 2
From: Gabriola BC
Re: rear main seal leaking? (wadey)
Possible that the plugs for the lifter galleries have a small weep. If you had the motor rebuilt around the time the leak started that might be a thought but if the plugs have been in for 30 years that probably isn't the case. If there was oil coming from the intake or oil sender I would think for enough to sneak down into the bellhousing there would be quite a bit dripping externally also. One last long shot, are you sure it is engiine oil because if you have a muncie, a plugged drain back hole can make a leak similar to what you have and with the flywheel and clutch spinning sometimes where it is coming from gets hard to tell. I still wouldn't count out your rear main seal.
bob
bob
Team Owner
Joined: Aug 1999
Posts: 30,995
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From: Ontario
Re: rear main seal leaking? (Richard Cooper)
Richard,
The dye is used by GM dealers to diagnose engine oil leaks. It sells over the counter for about $5.00.
The engine must be cleaned before dye is put into the crankcase. When to hit the engine with UV/black light is a little tricky and depends on the severity of the leak(s). For a moderate leak I suggest driving about 100 miles. For more severe leaks about 25-50 miles. The tricky part relates to the fact that leaks can merge into an oily mess and disguise their origin. Then you only see a nice pink oil pan and bell housing. Not very helpful. The nice side of the product is that the dye does not degrade. So if what I described happens, you can re-clean the mess and start again.
The dye is used by GM dealers to diagnose engine oil leaks. It sells over the counter for about $5.00.
The engine must be cleaned before dye is put into the crankcase. When to hit the engine with UV/black light is a little tricky and depends on the severity of the leak(s). For a moderate leak I suggest driving about 100 miles. For more severe leaks about 25-50 miles. The tricky part relates to the fact that leaks can merge into an oily mess and disguise their origin. Then you only see a nice pink oil pan and bell housing. Not very helpful. The nice side of the product is that the dye does not degrade. So if what I described happens, you can re-clean the mess and start again.
Instructor
Joined: Sep 2001
Posts: 171
Likes: 1
From: Rolla MO
Re: rear main seal leaking? (gtr1999)
Gary,
I purchased one online at http://0-0-0Checkmate.com/ (search on "black light"). The one
I bought was $7.95 + S&H and uses four AA batteries. There may be better deals, but this
light has worked well for me so far. :cheers:
Hank
I purchased one online at http://0-0-0Checkmate.com/ (search on "black light"). The one
I bought was $7.95 + S&H and uses four AA batteries. There may be better deals, but this
light has worked well for me so far. :cheers:
Hank
