Another oil weight question

[sohanrd]

Disabling the DFM system, via OBD, does not give any results, as well as using Range systems. The DFM still remains in the engine. The only option is to completely remove the system at the aggregate level.That's right, using 5-30 oil on the 5th generation leads to problems with hydraulic compressors on runs of 100,000 miles and beyond. It is clear that in light of the problems with the L87 engine, the problem with the hydraulic compensators is not so acute, but nevertheless, we already have such cars that went to 5-30 and 0-30. In fact, switching to 0-40 oil is an even worse situation with hydraulic compressors, but I think GM is doing this on purpose, trying to delay the big problem, the destruction of the liners and crankshaft. Choosing the lesser of evils, so to speak.

From my understanding, DFM lifter issues happen because the lifter does not collapse or re‑expand at the correct moment due to several factors such as improper oil maintenance, oil pressure instability, and wear of the locking pins and internal components caused by excessive collapse/expand cycles.

IMO, keeping DFM disabled theoretically keeps the lifter expanded all the time, which removes the dependency on precise oil flow timing and eliminates the wear caused by excessive repeated cycling. In this state, the lifter essentially operates like a regular LS style hydraulic roller lifter, with similar risk levels.

So, IMO, in theory, DFM disabler is a great way to reduce the risk by magnitudes.

 

[LSCALADE]

Check the calibration with HP Tuners and look at specifically the oil pump settings. I found on my 2020 5.3L the high pressure side was disabled (Set to enable at 7000rpm). I found that Poilce Tahoes also had AFM enabled but the pump was set to kick on at 3500rpm.

If yours is set to 7000rpm you may want to consider disabling the AFM and kicking high pressure at around 3000rpm. That alone should enable longevity. Also try to never use anything less than 5W30.

 

[sohanrd]

You have it backwards, 0w20 or any synthetic oil is thinner on cold starts and thickens to 20 after getting to operating temperature for synthetic oil. Conventional oil is thicker when cold and thins out when warm. So on cold starts your synthetic oil is thinner on the cold start and thickens to 20 after getting warm.

hah? thinner on cold temp and thickens when getting to operating temp?

0w-30

 

[Z15]

SAE 0W-20 was adopted by Honda and Toyota in 2009 for most gasoline-powered applications. They have some of the most dependable engines so its not the oil. Yet people who know absolutely nothing about motor oils think they can outsmart the engineers and use whatever makes them feel good. I'm sticking with 0W-20 in my 3.0L LZ0.

 

[Silverado4x4]

hah? thinner on cold temp and thickens when getting to operating temp?

View attachment 479179

0w-30

Read this I knew I was going to have to explain it, Straight from Castrol. SAE 0W20 Synthetic motor oil.
designed to flow as easily as a 0 weight oil in winter temperatures, yet behave like 20 weight oil once the engine has achieved its full operating temperature. This ensures that even in cold climates, oil will start to flow through the engine immediately, providing lubrication to critical engine parts.


It's a common misconception that the 'W' in viscosity descriptions stands for “weight.” In fact, it stands for “winter.” In the case of synthetic 0W-20 oil, this means that the oil functions at 0 weight oil in cold climates, but is as thick and viscous as a 20 weight oil once normal engine temperature has been reached.


Castrol’s range of low viscosity 0W-20 oils includes Castrol EDGE, an advanced full synthetic 0W-20 motor oil. It’s our strongest oil and is formulated to last, withstanding extreme pressure and temperatures. It’s the best option for those who want to push their car to its limits. Castrol GTX FULL SYNTHETIC 0W-20 motor oil is engineered to maximum wear and sludge protection.

 

[blanchard7684]

 

[sohanrd]

Read this I knew I was going to have to explain it, Straight from Castrol. SAE 0W20 Synthetic motor oil.
designed to flow as easily as a 0 weight oil in winter temperatures, yet behave like 20 weight oil once the engine has achieved its full operating temperature. This ensures that even in cold climates, oil will start to flow through the engine immediately, providing lubrication to critical engine parts.


It's a common misconception that the 'W' in viscosity descriptions stands for “weight.” In fact, it stands for “winter.” In the case of synthetic 0W-20 oil, this means that the oil functions at 0 weight oil in cold climates, but is as thick and viscous as a 20 weight oil once normal engine temperature has been reached.


Castrol’s range of low viscosity 0W-20 oils includes Castrol EDGE, an advanced full synthetic 0W-20 motor oil. It’s our strongest oil and is formulated to last, withstanding extreme pressure and temperatures. It’s the best option for those who want to push their car to its limits. Castrol GTX FULL SYNTHETIC 0W-20 motor oil is engineered to maximum wear and sludge protection.

Here the Castrol 0w20

Viscosity at 40C: 45
Viscosity at 100C (operating temp): 8.5

Plain and simple.

 

[Z15]

View attachment 479199

Here the Castrol 0w20

Viscosity at 40C: 45
Viscosity at 100C (operating temp): 8.5

Plain and simple.

One important spec missing; Volatility

Fact, dexos allows 13% loss
AI Overview
Engine oil volatility
refers to how easily oil evaporates ("boils off") when exposed to high engine temperatures. Higher volatility leads to increased oil consumption, sludge formation, and reduced protective capabilities, especially in hot-running turbocharged or direct-injection engines. It is measured by the Noack Volatility Test (ASTM D5800), which defines the percentage of weight lost at 250°C.
AMSOIL Signature Series 100% Synthetic Motor Oil

 

[sohanrd]

One important spec missing; Volatility

Fact, dexos allows 13% loss
AI Overview
Engine oil volatility
refers to how easily oil evaporates ("boils off") when exposed to high engine temperatures. Higher volatility leads to increased oil consumption, sludge formation, and reduced protective capabilities, especially in hot-running turbocharged or direct-injection engines. It is measured by the Noack Volatility Test (ASTM D5800), which defines the percentage of weight lost at 250°C.
AMSOIL Signature Series 100% Synthetic Motor Oil

Yes, that's why turbos need more frequent changes of whatever the oil they designed to use.

 

[Marky Dissod]

SAE 0W-20 was adopted by Honda and Toyota in 2009 for most gasoline-powered applications. They have some of the most dependable engines so its not the oil.

It's not JUST the oil. Honda & Toyoda built their engines to tighter tolerances/clearances than GM engines even before 0w20 became a thing.
Years later, GM's tolerances/clearances have not gotten any tighter, yet people insist that the L86/L87 were designed with 0w20 in mind.
If anyone ever bothered to do an in-depth assembly comparison between an L86/L87 vs a 6.2L LT1?

Yet people who know absolutely nothing about motor oils think they can outsmart the engineers and use whatever makes them feel good.
I'm sticking with 0W20 in my 3.0L LZ0.

You're confusing engineers with beancounters, while forgetting about and ignoring tribologists.
If you ever actually paid attention to and heeded what tribologists had to say about 0w20 vs 0w30,
your feelings would cognitively dissociate from what you just learned, because your post indicates that this is about feelings and not about the Stribeck curve.