Good morning.
Just purchased a 2008 Impala with the 3.5L V-6 with 15K on it. It has the OLM system and unknown oil in it right now.
Got me thinking about oil choices for it as well as wanting to do some long-term testing complete with UOA's with various OLM percent oil life as a standard. Might try Havoline 5w-30 (9.7 hot viscosity), PennzoilYB 5w-30, then PP 5w-30 and finally Amsoil SSO 5w-30. Note: GM has not yet back-spec'd these engines for 5w-20 oils (maybe waiting for GF-5). If and when they do I will definitely try the PennzoilYB/PP 5w-20 as well as Amsoil ASM oil.
Then I thought about different viewpoints on when to add any top-off oil. I always have keep it on the full mark, figuring maximum oil volume reduces TBN depletion. I mean I usually don't let it drop down more than 1/4 or 1/2 at the very most to the add line before adding oil.
Others here let it go all the way to the add line, with others adding at some point between the two extremes. And there's been some discussion here on if you add oil late in the change cycle it can skew the UOA results. I guess I'm wondering if the preferred method is to let it drop to the add line, refill to the full, repeating the process as needed?
I figured that if I consistently keep it at a specific level, whether that be full on the stick, or 1/4 down throughout the life of the oil, then good or bad, I can still rely on the TBN from a UOA as an accurate representation of the oil status.
I know highly respected individuals here, such as Doug Hillary, have stated that once they have the engine oil consumption pattern figured out, that they let the oil level drift down (always keeping above the add line) as the end of the oil cycle/UOA approaches.
And does running the oil level at the full line increase consumption/deposits, whether it be piston top or intake valve face as I read somewhere? I figured running at the full line protected against oil sludging/breakdown a little better.
Sorry about this long-winded post. I appreciate any insight.
Thanks,
Gary
Just purchased a 2008 Impala with the 3.5L V-6 with 15K on it. It has the OLM system and unknown oil in it right now.
Got me thinking about oil choices for it as well as wanting to do some long-term testing complete with UOA's with various OLM percent oil life as a standard. Might try Havoline 5w-30 (9.7 hot viscosity), PennzoilYB 5w-30, then PP 5w-30 and finally Amsoil SSO 5w-30. Note: GM has not yet back-spec'd these engines for 5w-20 oils (maybe waiting for GF-5). If and when they do I will definitely try the PennzoilYB/PP 5w-20 as well as Amsoil ASM oil.
Then I thought about different viewpoints on when to add any top-off oil. I always have keep it on the full mark, figuring maximum oil volume reduces TBN depletion. I mean I usually don't let it drop down more than 1/4 or 1/2 at the very most to the add line before adding oil.
Others here let it go all the way to the add line, with others adding at some point between the two extremes. And there's been some discussion here on if you add oil late in the change cycle it can skew the UOA results. I guess I'm wondering if the preferred method is to let it drop to the add line, refill to the full, repeating the process as needed?
I figured that if I consistently keep it at a specific level, whether that be full on the stick, or 1/4 down throughout the life of the oil, then good or bad, I can still rely on the TBN from a UOA as an accurate representation of the oil status.
I know highly respected individuals here, such as Doug Hillary, have stated that once they have the engine oil consumption pattern figured out, that they let the oil level drift down (always keeping above the add line) as the end of the oil cycle/UOA approaches.
And does running the oil level at the full line increase consumption/deposits, whether it be piston top or intake valve face as I read somewhere? I figured running at the full line protected against oil sludging/breakdown a little better.
Sorry about this long-winded post. I appreciate any insight.
Thanks,
Gary
