: Leaking Rear Main Seal Owners, Chime in !



Razorecko
03-13-11, 06:21 PM
Are all you guys using Mobil 1 ? If not than what oil ?

With Curtis/Cbloveday 2nd rear main seal leak I'm trying to figure out if its the mobil 1 breaking down the seal. I've heard on a couple of forums of Mobil1 5w-30 / oem oil , breaking down the seals....

Here is some interesting info...

http://www.gmfullsize.com/forum/showthread.php?t=203875

" Starting with 2011 vehicle production, GM no longer specifies Mobil 1 as the required oil for the above vehicles. A new oil specification called Dexos I has been created, which a variety of synthetic and synthetic blend motor oils meet "

Notice how the TSB only applies up to 2010 CTS-V vehicles. It might be an idea but what if mobil1 is eating up the seals ?

RapidRob
03-13-11, 06:48 PM
I replaced my oem oil at 1500 miles with AMSOIL Signiture 0-30 full synthetic. I had an oil leak and the dealer diagnosed an oil pan gasket leak, but no rear main seal leaking. After the oil pan gasket was replaced, I refilled with the AMSOIL oil and no leaking anywhere now. Current miles = 16K.

Rob

Razorecko
03-13-11, 06:54 PM
I started using Pennzoil Ultra GF-5 Grade approved GM oil ( Mobil 1 is GF-4 ) around 18k. I have almost 30k miles and had the rear main seal checked. Dry as a bone ( knock on wood ) ...Also have a manual / stickshift V if that makes any difference

cbloveday
03-13-11, 09:48 PM
Hmm that is interesting Raz. Subscribed.

tbss08
03-13-11, 09:54 PM
Mobil 1 oil changed every 3000 miles and leaking at 16 K. I also use Mobil 1 in my wife's TBSS with no leaks at 14K.

GM-4-LIFE
03-13-11, 09:56 PM
I did the first oil change at 5K miles and then I ran Amsoil 0w30 Signature Series from then on. My engine was leaking from day one, so I don't think Mobil 1 has anything to do with it. I think GM would have caught that issue years ago. They have been running Mobil 1 as factory fill for over a decade. I think we would have heard about this by now.

Razorecko
03-13-11, 09:58 PM
^ the only other thing I could think of is when someone uses their V in the winters they put their main seal through many more cold/hot cycles than if its just a nice weather ride therefore breaking down the seal much quicker

GM-4-LIFE
03-13-11, 10:01 PM
Could be, but I live in Los Angeles and we don't have cold winters and mine leaked since day one.

tbss08
03-13-11, 10:02 PM
I was shooting the bull with the service adviser at the dealership when the subject of the 2011's and free maintenance came up. GM has the dealer use the GM brand of synthetic oil, must be something like Walmart with the Great Value brand.
I don't believe GM switched from Mobil 1 for any issues other than cost.

Gary Wells
03-14-11, 10:52 AM
Any relationship between the leaking ones and whether the car is an auto or a stick?

cbloveday
03-14-11, 11:17 AM
Mine is auto.

baabootoo
03-16-11, 12:43 PM
I was looking at an AMG before this, and read the boards for many months. They too changed their Mobil 1 oil specs for cars late 2009/early 2010. The original was a "special blend" 5W-30. They then went up to a 5W-40; some call it the European blend. Of course Merecdes didn't have a concrete answer either. I could never figure out how/why the weather in Europe could be any different than US weather either. Maybe the Mercedes guy knows more than me.

lbenoit
03-16-11, 02:56 PM
My dealer just determined today that my 2009 CTS-V has an slight oil leak in the area where the transmission mates with the engine block. I have a little under 18,000 miles on my car. A GM technical service bulletin indicated that the problem is caused by engine block porosity in the area of the main seal.

Also, Mobil 1 5W-30 meets the GM Dexos specficiation according to the Mobil 1 website and has been used exclusively for my oil changes. For more information go to mobiloil dot com.

cbloveday
03-16-11, 04:17 PM
My dealer just determined today that my 2009 CTS-V has an slight oil leak in the area where the transmission mates with the engine block. I have a little under 18,000 miles on my car. A GM technical service bulletin indicated that the problem is caused by engine block porosity in the area of the main seal.
Also, Mobil 1 5W-30 meets the GM Dexos specficiation according to the Mobil 1 website and has been used exclusively for my oil changes. For more information go to mobiloil dot com.

Yes, that is the case. I had the repair done and I still leaked. The lsx block should resolve the matter for me.

Razorecko
03-16-11, 05:46 PM
Hmm. I wonder. Jesse showed me how some of the new v's have heads that are also dimpled/porous. I wonder if this is something thats a similar issue to the rear main seal problem. It would def be something along "bad batches" of motors / heads

GARBAJ
03-16-11, 06:16 PM
You guys are instilling a lot of confidence in my buying a new one of these cars... Between this rear main deal and the aforementioned leaking panoramic roofs of late, I'm getting a bit uninspired... Maybe I'm spending too much time on the board looking for this stuff!

shade
03-16-11, 06:59 PM
I started using Pennzoil Ultra GF-5 Grade approved GM oil ( Mobil 1 is GF-4 ) around 18k. I have almost 30k miles and had the rear main seal checked. Dry as a bone ( knock on wood ) ...Also have a manual / stickshift V if that makes any difference


I just looked at this oil on their site and its a gf-4 approved level now and exceeds gf-5 but not yet certified it looks like...?

Caddy Wagon
03-16-11, 07:33 PM
You guys are instilling a lot of confidence in my buying a new one of these cars... Between this rear main deal and the aforementioned leaking panoramic roofs of late, I'm getting a bit uninspired... Maybe I'm spending too much time on the board looking for this stuff!

lol. Every car forum I have ever been on has been this way. The bad/negative things tend to be highlighted. It seems to be worse on forums where the vehicle is performance oriented.

C66 Racing
03-19-11, 08:57 AM
I was looking at an AMG before this, and read the boards for many months. They too changed their Mobil 1 oil specs for cars late 2009/early 2010. The original was a "special blend" 5W-30. They then went up to a 5W-40; some call it the European blend. Of course Merecdes didn't have a concrete answer either. I could never figure out how/why the weather in Europe could be any different than US weather either. Maybe the Mercedes guy knows more than me.

In general, the reason that cars marketed in the U.S. are using fluids with dropping viscosity is due to the fluids impact on CAFE. GM for example sells the C6 Z06 in the U.S. with Mobil 1 5w30 in it, whereas in Europe the same engine comes with Mobil 1 0w40.

FYI, regards the post of using the AMSOIL Signature Series Synthetic 0w30 (http://www.c66racing-synthetics.com/Product%20Bulletins/SSOPB.htm) (Product Code SSOQT), that is the same fluid I used in my 06, but it is not yet labeled for the new Dexos spec, though I believe that AMSOIL will do so this year. They do have two of their lower tier synthetics that meet the new Dexos spec for any that may be interested:
AMSOIL XL Synthetic 5w30 (http://www.c66racing-synthetics.com/Product%20Bulletins/XLFPB.htm) (Product Code XLFQT)
AMSOIL OE Synthetic 5w30 (http://www.c66racing-synthetics.com/Product%20Bulletins/OEFPB.htm) (Product Code OEFQT)

As always, for those interested in AMSOIL, I'm more than happy to ensure forum members can get AMSOIL at dealer wholesale pricing, about 25% below retail, via the AMSOIL Preferred Customer Program (http://www.c66racing-synthetics.com/Preferredcustomer.htm). Drop me a PM if interested. :cheers: