[NW-99SS]

Originally Posted by waterman

The response albeit brief, makes perfect sense to me.

With oil temps in the LT4 approaching and perhaps exceeding 250F+ under heavy load, I (personally) would never trust a 0W-40 or 5W-40. 5W or 15W-50 makes perfect sense to me. Especially considering that a motor oil with low ash content, though it preserves our CATs and significantly lowers the coking and varnishing effects of GDI, will sacrifice the additive profile that reduces wear. At 250+ oil temp, 50W is about as thick as water, I want all of the viscosity and wear protection that I can get.

I will change out more frequently with a low ash Dexos 2. Understanding that with a low ash profile, my intake valves and blower bricks are better protected from the goop introduced by the PCV. However, the compromise is that my wear protection profile is reduced because those same high ash components are what protects my internal components from wear.

The question however, remains somewhat unanswered; Is M1 ESP 0W-40, now a recommended fill for pre 2019 Gen 6 LT1/4?

With motors that run on the street with oil temps at 210+, I truly hope so. IMHO, at the oil temps that an LT4 operate, 5W-30 lacks the viscosity to protect our powerplants long term.

I personally will run 0W or 5W-40 Dexos 2 on the street. I will always run at least a 5W or 15W-50 under heavy load/track conditions.

Do your research gentlemen/ladies; there is a significant difference between 100% synthetic and full synthetic. SIGNIFICANT!

Agreed - good post.

Can I ask why you wouldn't run a catch can? This will alleviate your PCV concerns and I suggest all GM DI engines should have some sort of catch can setup to maintain intake tract and valve cleanliness (I run a Mighty Mouse on my Denali 6.2).