Rear Main Seal Leak

[RoGuE]

When my dads 2002 Suburban 5.3L with 124k miles was in for a u joint repair, the tech said he noticed the rear main seal was leaking. Now, I've never seen a single spot of oil on the driveway, so I assume it only leaks when the engine is running and the pressure pushes it out. It needs a quart of oil every 1300 miles or so, but I always just assumed it burned it. It's been losing a qt/1300 miles for over 5 years now.

Anyway, the point of this is to find out if moving to a different oil viscosity will help it out. I have been putting PYB 5w-30 in it for years now.

 

[Bluestream]

Try a high mileage oil

 

[rfeir]

Exactly; or add a rear seal conditioner. This worked wonders on my sailboat's Westerbeak motor.

 

[demarpaint]

A HM oil or Lubro Moly makes a product called Motor Oil Saver IIRC. It is good for leaking engines, and got some good reports here on Bitog.

 

[eagle23]

One other thought: keep on keeping on.

Nothing's changed in 5 years; it's really consistent from what you've said.

But then being a BITOGer, you may proceed to over-think the problem [he said with self-accusation] ;-)

THAT said, the LubroMoly product gets good reviews as does AT-205 Reseal. I tried the former with no changes and haven't (yet) tried the latter. I understand it's only available at repair shops.

One plus is the rear mains on the Chevy may not be an expensive repair depending which one you have.

 

[TFB1]

Originally Posted By: RoGuE
tech said he noticed the rear main seal was leaking. Now, I've never seen a single spot of oil on the driveway,


A leak of 1300mi qt WILL leave telltale signs, likely it's burning more than it's leaking...

 

[Boss302fan]

Do a few oci's with Maxlife HM 5W30...

 

[blmlozz]

I wouldn't expect any miracles with the suggestions above, HM and higher viscosity oils will help to a degree. Just don't go in expecting to half the rate that it's consuming at the moment. As suggested though, a RMS in a Small Block really isn't that big of a job on a large truck-- infact a complete reseal isn't that big a deal on a SBC, you're only talking about a single cam seal, oil pan, VCG's, VSS's if you want, and RMS in total.. However, I would expect alot of that is blow-by from the rings if you're not seeing visable remnants on the pavement, more so since we're talking about a SBC-- the list of 100K+ GM V8's which do not consume oil that I know of is very small.

 

[buster]

M1 HM helped fix the real main seal leak my brother had in his Toyota V6. He now has almost 300k miles on it.

 

[Bluestream]

Originally Posted By: TFB1
Originally Posted By: RoGuE
tech said he noticed the rear main seal was leaking. Now, I've never seen a single spot of oil on the driveway,


A leak of 1300mi qt WILL leave telltale signs, likely it's burning more than it's leaking...


True, but we don't know how much is being burnt, and how much leaks out. If a lot were leaking out, there would be marks on the driveway for sure...

 

[RoGuE]

Thanks for the replies!

I forgot to mention that I had used Pennzoil HM for probably the past 2 years, except for the last couple OCIs due to the rising cost of it compared to the conventionals and the fact that I never noticed a difference in oil loss.

 

[Bluestream]

Originally Posted By: RoGuE
Thanks for the replies!

I forgot to mention that I had used Pennzoil HM for probably the past 2 years, except for the last couple OCIs due to the rising cost of it compared to the conventionals and the fact that I never noticed a difference in oil loss.


Oh...your first post says: I have been putting PYB 5w-30 in it for years now.

 

[RoGuE]

I apologize. I forgot about it due to the fact that it never made a difference compared to regular PYB.

I currently use 5w-30 all year round. Could a thicker oil like 5w-40 or 10w-40 help?