Oil weight for 5.3? 0-20 no good?

[viven44]

Here is a viscosity/flow demo on 10W-40 that I shot recently after replacing the valve stem seals on an old BBF

30 secs after cold start --- not much flow.. clearly the bearings and other components are designed to handle this 'sludge' for a little while

Watch Oil flow cold 30 secs | Streamable

Watch "Oil flow cold 30 secs" on Streamable.

streamable.com

Close to fully hot --- what a difference

Watch Oil flow fully hot | Streamable

Watch "Oil flow fully hot" on Streamable.

streamable.com

 

[Z15]

LOL, you know that the oil pumps are positive displacement right?

Positive displacement, meaning that for one revolution they pump the same volume of fluid regardless. Your graph above is only true for rotodynamic style pumps and totally not applicable to a forced oil lubrication system that uses a positive displacement pump.
...

So in your opinion thicker liquid flows just as fast as thin liquid?

 

[vcode]

So in your opinion thicker liquid flows just as fast as thin liquid?

Thickness and viscosity are related, but only viscosity is definable. It is the resistance to flow. Generally speaking, a thicker liquid will not flow as fast as a thinner one on its own. Put it in a PD pump and it will flow the same per revolution, but the more viscous fluid will require more energy to do so.

 

[Scarey]

Thickness and viscosity are related, but only viscosity is definable. It is the resistance to flow. Generally speaking, a thicker liquid will not flow as fast as a thinner one on its own. Put it in a PD pump and it will flow the same per revolution, but the more viscous fluid will require more energy to do so.

And that’s probably why gm went to 0-20. Take less energy to pump meaning better mpg. I think the evidence is pretty clear 20wt for mpg and 40 for engine longevity. Not saying this is cause of latest mess, just an observation.

 

[vcode]

And that’s probably why gm went to 0-20. Take less energy to pump meaning better mpg. I think the evidence is pretty clear 20wt for mpg and 40 for engine longevity. Not saying this is cause of latest mess, just an observation.

Well I'd like to see evidence of any kind that actually quantifies if/how much better 40 is for longevity. Lots of speculation. There are millions of non-GM vehicles out there running 0W20 for over a decade without issues.

 

[GMCChevy]

Well I'd like to see evidence of any kind that actually quantifies if/how much better 40 is for longevity. Lots of speculation. There are millions of non-GM vehicles out there running 0W20 for over a decade without issues.

Even GM vehicles.

 

[viven44]

Found this bulletin from 2013, it sure looks like GM made a big push for 0W-20 back then for 2014 year models

https://static.nhtsa.gov/odi/tsbs/2013/MC-10246634-9999.pdf

saying that apparently

"These engines utilize an advanced combustion system that maximizes the potential of the direct injection (DI) fuel system, active fuel management (AFM), variable valve timing (VVT), two stage oil pumps and other technologies. The dexos1™ 0W20 oil supports these technologies"

but they sure have walked back in the face of the recall and saying 0W-40 is better in the suspect engines (I doubt they have volume reliability data to back that up, this doing so must fundamentally suggest that they believe 0W-40 is better on the 6.2L and has the best chance of taking those engines to the "finish line" despite the use of all these awesome fuel savings technologies like DFM, DI)

More from the bulletin.
Question: Can another oil such as 5W30 that is cheaper and more widely available be used in place of dexos1™ 0W20oil?

Answer: No. The 5.3L and 6.2LV8 EcoTec3 engines available in the 2014 Silverado 1500 and Sierra 1500 pickup trucks were designed, engineered and validated to run using dexos1™ 0W20 oil. This is the ONLYoil approved for these engines.

Needing more comparative data will take years and unfortunately not be possible if everyone keeps using 0W-20. All we know is the GMT800/900 engines easily went to 300K on 5W-30. How many 200K engines have we seen here on 2015+ year models ? It’s gonna take more years to see how reliable these are. Our 2018 Tahoe sure started having some problems around the 90K mark.. oil burning, intermittent blinking misfire CELs after long trips, etc

 

[Scarey]

The oil geek makes a pretty compelling argument for oil a little thicker than 20.

 

[GMCChevy]

Found this bulletin from 2013, it sure looks like GM made a big push for 0W-20 back then for 2014 year models

https://static.nhtsa.gov/odi/tsbs/2013/MC-10246634-9999.pdf

saying that apparently

"These engines utilize an advanced combustion system that maximizes the potential of the direct injection (DI) fuel system, active fuel management (AFM), variable valve timing (VVT), two stage oil pumps and other technologies. The dexos1™ 0W20 oil supports these technologies"

but they sure have walked back in the face of the recall and saying 0W-40 is better in the suspect engines (I doubt they have volume reliability data to back that up, this doing so must fundamentally suggest that they believe 0W-40 is better on the 6.2L and has the best chance of taking those engines to the "finish line" despite the use of all these awesome fuel savings technologies like DFM, DI)

More from the bulletin.
Question: Can another oil such as 5W30 that is cheaper and more widely available be used in place of dexos1™ 0W20oil?

Answer: No. The 5.3L and 6.2LV8 EcoTec3 engines available in the 2014 Silverado 1500 and Sierra 1500 pickup trucks were designed, engineered and validated to run using dexos1™ 0W20 oil. This is the ONLYoil approved for these engines.

Needing more comparative data will take years and unfortunately not be possible if everyone keeps using 0W-20. All we know is the GMT800/900 engines easily went to 300K on 5W-30. How many 200K engines have we seen here on 2015+ year models ? It’s gonna take more years to see how reliable these are. Our 2018 Tahoe sure started having some problems around the 90K mark.. oil burning, intermittent blinking misfire CELs after long trips, etc

2014 was 11 years ago it shouldn't be that hard to find work trucks or even regular drivers with 200k+ on them. I think there are some members floating around the forum who posted mileage up there in some of the reliability anf mileage posts.

 

[viven44]

2014 was 11 years ago it shouldn't be that hard to find work trucks or even regular drivers with 200k+ on them. I think there are some members floating around the forum who posted mileage up there in some of the reliability anf mileage posts.

No, I just checked an auction I have membership at; there are plenty of 200K+ mile trucks listed there 2014 and newer with very few having mechanical faults so I have no doubts the 0W-20 can take it past 200K..... interestingly 5.3L to 6.2L showing up at a 25:1 ratio for 200K+ mile ones, and at a 12:1 ratio for <100K mile ones....

 

[Antonm]

So in your opinion thicker liquid flows just as fast as thin liquid?

No, it’s not an opinion, it’s just physics.

Positive displacement pumps ( like most automotive oil pumps are) pump the same volume of fluid per revolution regardless of fluid viscosity.

Yes pressure will be higher and it’ll take more power to turn the pump, but it’ll put out the same volume of fluid with either weight oil.
…

 

[vcode]

Found this bulletin from 2013, it sure looks like GM made a big push for 0W-20 back then for 2014 year models

https://static.nhtsa.gov/odi/tsbs/2013/MC-10246634-9999.pdf

saying that apparently

"These engines utilize an advanced combustion system that maximizes the potential of the direct injection (DI) fuel system, active fuel management (AFM), variable valve timing (VVT), two stage oil pumps and other technologies. The dexos1™ 0W20 oil supports these technologies"

but they sure have walked back in the face of the recall and saying 0W-40 is better in the suspect engines (I doubt they have volume reliability data to back that up, this doing so must fundamentally suggest that they believe 0W-40 is better on the 6.2L and has the best chance of taking those engines to the "finish line" despite the use of all these awesome fuel savings technologies like DFM, DI)

More from the bulletin.
Question: Can another oil such as 5W30 that is cheaper and more widely available be used in place of dexos1™ 0W20oil?

Answer: No. The 5.3L and 6.2LV8 EcoTec3 engines available in the 2014 Silverado 1500 and Sierra 1500 pickup trucks were designed, engineered and validated to run using dexos1™ 0W20 oil. This is the ONLYoil approved for these engines.

Needing more comparative data will take years and unfortunately not be possible if everyone keeps using 0W-20. All we know is the GMT800/900 engines easily went to 300K on 5W-30. How many 200K engines have we seen here on 2015+ year models ? It’s gonna take more years to see how reliable these are. Our 2018 Tahoe sure started having some problems around the 90K mark.. oil burning, intermittent blinking misfire CELs after long trips, etc

So this is only a guess..... but I would think that 0w20 full synthetic is at least as good, if not better than the 5W30 dino used in my 2010 Tahoe. Oil has come a long way since then and it takes a pretty good base stock to make a 0W anything oil.

 

[GMCChevy]

No, I just checked an auction I have membership at; there are plenty of 200K+ mile trucks listed there 2014 and newer with very few having mechanical faults so I have no doubts the 0W-20 can take it past 200K..... interestingly 5.3L to 6.2L showing up at a 25:1 ratio for 200K+ mile ones, and at a 12:1 ratio for <100K mile ones....

I'm guessing that's probably also close to the ratio of the number of trucks with the different engines since most purchasers wouldn't pay more for the bigger engine and if they needed more they'd go diesel.

 

[downtheroadar]

Interesting looking at percentages of difference over temp.

Kinematic viscosity is a measure of a fluid's resistance to flow under the influence of gravity. It essentially describes how easily a fluid flows when it's not being actively pushed or pulled by an external force (other than gravity). It's the ratio of a fluid's dynamic viscosity to its density.

• Lower cSt values indicate a thinner oil that flows more easily (better for fuel efficiency and cold starts)
• Higher cSt values indicate thicker oil (better for high-temperature protection).
• Measurement: Kinematic viscosity is typically measured at 40°C (104°F) and 100°C (212°F) for motor oils, as these temperatures reflect typical engine operating conditions.

Any errors are Groks. Just had it tell me this then asked to write python to graph it. My wife has a 23 Yukon 5.3

Automotive engine oil pumps do not necessarily pump at the same rate regardless of viscosity, as oil viscosity significantly affects the pump's performance. Here’s a concise explanation:

Key Points:

• Oil Pump Design: Most automotive engines use positive displacement pumps (e.g., gear or gerotor pumps), which are designed to move a fixed volume of oil per revolution or cycle, theoretically delivering a consistent flow rate regardless of viscosity.
• Viscosity Impact:
  • Higher Viscosity (e.g., 0W-40 at low temperatures): Thicker oil increases resistance to flow, causing higher pressure in the pump and potentially reducing the actual flow rate slightly due to internal leakage or pump inefficiency. The pump may also require more engine power to operate.
  • Lower Viscosity (e.g., 0W-20 at high temperatures): Thinner oil flows more easily, reducing pressure and allowing the pump to maintain its designed flow rate more effectively, but it may lead to lower oil pressure if too thin for the engine’s design.
• Pressure Regulation: Most engines have a pressure relief valve in the oil system. If viscosity is high (e.g., cold 0W-40 at 0°F, ~300 cSt), the pump generates higher pressure, and the relief valve may open to prevent damage, diverting excess oil back to the sump, which can reduce the effective flow to the engine.
• Temperature Effects: From your viscosity data, 0W-20 and 0W-40 have similar viscosities at low temperatures (e.g., 300 cSt at 0°F), so the pump’s flow rate would be similar in cold conditions. At higher temperatures (e.g., 300°F, where 0W-20 is ~4.6 cSt and 0W-40 is ~7.5 cSt), the thinner 0W-20 flows more easily, potentially leading to lower pressure but similar pump flow if the system is within design limits.
• Engine Design: The pump’s flow rate is tuned to the engine’s requirements. Viscosity variations (within SAE specifications) are accounted for, but extreme viscosities outside the recommended range (e.g., using a very thick oil in a system designed for thin oil) can cause insufficient flow or excessive pressure.

Practical Implications:

• Cold Starts: At 0°F, both 0W-20 and 0W-40 have high viscosity (~300 cSt), so the pump works harder, and flow may be slightly reduced due to pressure relief valve action.
• Operating Temperatures: At 212°F, 0W-20 (8.5 cSt) flows more easily than 0W-40 (14.0 cSt), potentially resulting in lower oil pressure for 0W-20, but the pump’s volumetric flow rate remains nearly constant unless limited by system design.
• Pump Efficiency: Positive displacement pumps aim for constant flow, but real-world factors like internal clearances, pump wear, or extreme viscosities can cause minor flow variations.

Conclusion:

While automotive oil pumps are designed to deliver a consistent flow rate, viscosity affects pressure and pump effort more than flow rate. Higher viscosity oils (like 0W-40 at lower temperatures) increase pressure and may trigger the relief valve, slightly reducing effective flow to the engine. Lower viscosity oils (like 0W-20 at higher temperatures) maintain flow but may result in lower pressure. For 0W-20 and 0W-40, the flow rate differences are minimal within typical operating conditions, as both oils are designed for similar cold-start performance (0W rating).

Supplement

 

[B-train]

How much gas mileage does one gain by going from 5w-30 to 0w-20?

Ummm..........like nothing in the real world from what I've experienced. Maybe in the arctic if you are always starting it at negative F temps, but how would it be calculated anyways?

It can/has been done in a test cell, and on a calibrated drive cycle I'm sure to verify the savings to justify it's existence........but I wouldn't bet my motor on it.

The last tank I drove with my 2017 with a 6.2L in it for a business trip I got 21.8 mpg mixed between highway and 2 lane roads. AFM tuned off, running on good old 5w-30 full synthetic. No hyper-miling, driving with (and faster) than traffic, just being sensible and listening to the truck. All while nearing the end of its change cycle with about 4400 miles on it, so the super slippery new feeling has lessened by this point.

My next test will be on my 2025 Malibu with the 1.5L turbo motor. It gets 0w-20 from the factory I believe, but my plan is to use the 5w-30 dexos I buy in bulk. I have a good idea of the MPG for both city and highway by now, so I'm excited to see if there is any real change.

If there is a difference, it should be more noticeable on a smaller fella with less horses running around under the hood......

 

[blanchard7684]

Sommerfeld calculations show that the 5.3 can get away with 0w20. There is a small margin of viscosity above that which is needed for maximum bearing load support.

5w30 gives a higher margin vs 0w20.

I have been running 5w30 in my 5.3 suburban for a while and the mpg is not showing a difference that is above the “noise” of things like wind, and driving manner.

The same analysis for a 6.2 shows that for maximum bearing support 0w40 is ideal. 0w20 is a good ways off from delivering maximum support.

I attempted same analysis for 3.0 diesel but I’m not convinced I have a good source for accurate information on bearing dimensions and typical rpm ranges in each gear.

 

[jfoj]

A few notes, for a long time, probably over 10+ years these GM V8 engines have been using variable displacement oil pumps. Some even were 2 stage, the L87 still is 2 stage. The 2 stage pumps are all variable vane style pumps, like an automatic transmission style oil pump, but the 2nd stage is a solenoid control that boosts the oil pressure.

I think the main reason all these manufacturers are using 0W blends is for the Auto Stop/Start to build oil pressure quickly even at warmer temps

Why anyone would continue to run 0W20 oil in these engines is beyond my pay grade. I do not care about fuel economy I care about reliability. Even GM recommends 0W40 now that their back is against the wall!

 

[vcode]

A few notes, for a long time, probably over 10+ years these GM V8 engines have been using variable displacement oil pumps. Some even were 2 stage, the L87 still is 2 stage. The 2 stage pumps are all variable vane style pumps, like an automatic transmission style oil pump, but the 2nd stage is a solenoid control that boosts the oil pressure.

I think the main reason all these manufacturers are using 0W blends is for the Auto Stop/Start to build oil pressure quickly even at warmer temps

Why anyone would continue to run 0W20 oil in these engines is beyond my pay grade. I do not care about fuel economy I care about reliability. Even GM recommends 0W40 no that their back is against the wall!

Blah blah blah...... Tens of millions of engines running hundreds of billions of miles on 0W20 with no issues, including GM's 5.3L. GM is only using 0W40 on recalled motors. New trucks still use 0W20. You say you should change tranny fluid every 8K miles. That's just insane. Might as well just put a 55 gallon drum in the back of your truck to continuously feed it new fluid.....

 

[jfoj]

Blah blah blah...... Tens of millions of engines running hundreds of billions of miles on 0W20 with no issues, including GM's 5.3L. GM is only using 0W40 on recalled motors. New trucks still use 0W20. You say you should change tranny fluid every 8K miles. That's just insane. Might as well just put a 55 gallon drum in the back of your truck to continuously feed it new fluid.....

Suit yourself. 0W20 is garbage for how these vehicles are tuned, the power they put out and the weight they carry. Drink the 0W20 Koolaid all you want. There is a subset of smaller, lighter vehicles with less powerful engines that might survive on 0W20, but I am not putting the Koolaid in my vehicles.

As for the transmission, with a stock trans pan you are lucky to get 5 quarts out when you drop the pan, probably closer to 4. But you will never know if you have a V8 because you will never drop the trans pan.

 

[vcode]

Suit yourself. 0W20 is garbage for how these vehicles are tuned, the power they put out and the weight they carry. Drink the 0W20 Koolaid all you want. There is a subset of smaller, lighter vehicles with less powerful engines that might survive on 0W20, but I am not putting the Koolaid in my vehicles.

As for the transmission, with a stock trans pan you are lucky to get 5 quarts out when you drop the pan, probably closer to 4. But you will never know if you have a V8 because you will never drop the trans pan.

Again, show me all the oiling issues with 5.3L's produced since 2013. Heck, include 6.2L's as well that are not affected by the recall due to improperly machined parts. Your world and the real world are light years apart. Nobody is going to spend $500 or more every other oil change to get their transmission fluid changed.