Why does the 4.3l use 5w-30 oil and the 5.3l use 0w-20?

newdude · October 12, 2022

2 hours ago, Jayselectricco said:

I absolutely agree that 5W-30 is better at protecting engines... my thought is this... since the 4.3 and 5.3 are pretty much the same except ones a 6 cyl and ones an 8, that they knew the 6cyl would get the gas mileage no problem but the 5.3 needed 0w-20 to achieve the number it needed.

That's because of 100% of trucks built, 65% were 5.3, 25% were 6.2 and 10% 4.3. These aren't exact numbers, but just trying to make a point. Those 90% of V8 trucks is where it counts the most for efficiency for CAFE.

Edited October 12, 2022 by newdude

customboss · October 12, 2022

3 hours ago, Jayselectricco said:

That makes sense, however the 4.3 has the AFM too so why wasn't it made to use the 0w20 as well?

Different hydraulic needs and less HP, less TQ demands etc. Is not just a V8 with 2 power cylinders removed.

customboss · October 12, 2022

2 hours ago, newdude said:

That's because of 100% of trucks built, 65% were 5.3, 25% were 6.2 and 10% 4.3. These aren't exact numbers, but just trying to make a point. Those 90% of V8 trucks is where it counts the most for efficiency for CAFE.

SAE rated viscosity delta is not going to impact CAFE of a fleet.

Hydraulic behavior for emissions and associated improved MPG test cycles with lower dynamic vis to tune for the AFM behavior.

https://fueleconomy.gov/feg/how_tested.shtml

Grumpy Bear · October 13, 2022

4 hours ago, customboss said:

Hydraulic behavior for emissions and associated improved MPG test cycles with lower dynamic vis to tune for the AFM behavior.

Viscosity has zero 'real time' effect on the hydraulics at normal operating temperatures. Liquids not aerated are not compressible. The difference in these two under normal temps is so small....yea.....zip.

OP, you OLM does not measure nor monitor the oils viscosity.

Z45 · October 13, 2022

GM's reason

Quote

Oil capacity has been increased to six quarts for the 4.3L V-6 and eight quarts for the V-8 engines. All engines use GM’s Dexos oil for increased fuel efficiency and longer oil life, and V-8s are engineered to use 0W/20 oil to improve lubrication and reduce friction.

Edited October 13, 2022 by elcamino

pokismoki · October 13, 2022

21 hours ago, customboss said:

If I had to guess 0w20 was indicated for newer 5.3's for more stable hydraulic reliability for AFM. The delta in HTHS or wear protection from 5w30 to 0w20 is negligible in the 5.3 design. But the 5w30 will drive a higher hydraulic pressure thats not needed and can change valve timing dynamically.

yes, but no...lol 0w-20 is to reduce friction and meet emmissions reqs for the feds.

have to take into account, as the oil is loosing its polymer thickening due to wear and tear, and lack of proper oil changes.

utilizing the trucks extremly long OCI measurement system while running 0w-20 will have far more destructive results, than say a cheap 5w-30 on a healthy diet of 3000-4000 mile OCI

Grumpy Bear · October 13, 2022

12 hours ago, elcamino said:

Oil capacity has been increased to six quarts for the 4.3L V-6 and eight quarts for the V-8 engines. All engines use GM’s Dexos oil for increased fuel efficiency and longer oil life, and V-8s are engineered to use 0W/20 oil to improve lubrication and reduce friction.

Carefully crafted wording. :rolleyes: Somebody was earning their keep. :crackup:

Thanks for sharing that Mike!

customboss · October 13, 2022

8 minutes ago, pokismoki said:

yes, but no...lol 0w-20 is to reduce friction and meet emmissions reqs for the feds.

have to take into account, as the oil is loosing its polymer thickening due to wear and tear, and lack of proper oil changes.

utilizing the trucks extremly long OCI measurement system while running 0w-20 will have far more destructive results, than say a cheap 5w-30 on a healthy diet of 3000-4000 mile OCI

The more dynamically viscous a fluid is for cam phasing technology you will tend to lean the fuel burn mechanically, then the ECM will counter by adding more fuel.

pokismoki · October 13, 2022

5 minutes ago, customboss said:

The more dynamically viscous a fluid is for cam phasing technology you will tend to lean the fuel burn mechanically, then the ECM will counter by adding more fuel.

trying to hurt my brain with all this over-thinking... : )

customboss · October 13, 2022

16 minutes ago, pokismoki said:

trying to hurt my brain with all this over-thinking... : )

Thats what our trucks do, one system off screws up the other systems, ask GrumpyBear!

Jayselectricco · October 13, 2022

3 hours ago, customboss said:

Thats what our trucks do, one system off screws up the other systems, ask GrumpyBear!

Just like when my thermostat was bad, my temp never got up to 210, so the truck was still in "warm up mode" In warm up mode the 2 stage oil pump stays in high pressure mode until it gets to temperature. So the truck gave a P06DD "stuck in high pressure oil mode" lol. Once I replaced my thermostat the temp came up to 210 and code went away. The code I got was nothing related to coolant problems, but it was that system causing the oil pump code. Crazy that the ECU was commanding the oil pump solenoid to stay in the high mode, and then give a CEL of stuck in high mode at the same time. I'm glad I didn't spend $1200 getting the oil pump replaced, just to see the CEL come back on.

And thanks everyone for the replies, I was just curious about why that more than one person I have talked to with the 4.3 that has this code makes it go away with an oil change, but then comes back right before the next oil change. Once they change the oil again then the code is gone until close to the next oil change... I don't buy that it's the oil pump stuck in high mode, because it obviously switches between the modes for several thousand miles without any code. When you look up this code it says the first things that could cause this code is LOW OIL, WRONG OIL VISCOSITY, WRONG OIL FILTER, and then the OIL PUMP bad. So if the truck isn't sensing the viscosity of the oil, then how can the wrong oil cause this? Is it sensing the flow of the oil? And the flow changing when the oil breaks down or gets dirty? Or is it just that the engine is using oil due to the AFM and is over a quart low causing their code? My 4.3 will use about a quart every 2k miles and I have heard that's normal because of the AFM. Maybe that is what is happening... people have told me that if it gets over a quart low then the CEL will come on, but they never mentioned what code it was. Could it be that P06DD is the generic code that comes up when you have low oil?

newdude · October 13, 2022

21 minutes ago, Jayselectricco said:

Just like when my thermostat was bad, my temp never got up to 210, so the truck was still in "warm up mode" In warm up mode the 2 stage oil pump stays in high pressure mode until it gets to temperature. So the truck gave a P06DD "stuck in high pressure oil mode" lol. Once I replaced my thermostat the temp came up to 210 and code went away. The code I got was nothing related to coolant problems, but it was that system causing the oil pump code. Crazy that the ECU was commanding the oil pump solenoid to stay in the high mode, and then give a CEL of stuck in high mode at the same time. I'm glad I didn't spend $1200 getting the oil pump replaced, just to see the CEL come back on.

And thanks everyone for the replies, I was just curious about why that more than one person I have talked to with the 4.3 that has this code makes it go away with an oil change, but then comes back right before the next oil change. Once they change the oil again then the code is gone until close to the next oil change... I don't buy that it's the oil pump stuck in high mode, because it obviously switches between the modes for several thousand miles without any code. When you look up this code it says the first things that could cause this code is LOW OIL, WRONG OIL VISCOSITY, WRONG OIL FILTER, and then the OIL PUMP bad. So if the truck isn't sensing the viscosity of the oil, then how can the wrong oil cause this? Is it sensing the flow of the oil? And the flow changing when the oil breaks down or gets dirty? Or is it just that the engine is using oil due to the AFM and is over a quart low causing their code? My 4.3 will use about a quart every 2k miles and I have heard that's normal because of the AFM. Maybe that is what is happening... people have told me that if it gets over a quart low then the CEL will come on, but they never mentioned what code it was. Could it be that P06DD is the generic code that comes up when you have low oil?

P06DD is oil pump solenoid control valve performance/stuck off.

Quote

If no other DTCs are set

Verify the condition does not exist: Engine Oil — Contaminated / Dirty / Fill Level = Low

Quote

The engine oil pressure control solenoid is a two port solenoid valve used to control engine oil pressure inside the mechanical engine oil pump. The ECM controls the commanded states of the engine oil pressure control solenoid with the following ECM input’s.

Engine Speed

Engine Oil Temperature (calculated from the Engine Coolant Temperature Sensor)

Engine Oil Pressure

Engine Run Time

With the engine oil pressure control solenoid commanded Off, engine oil pressure is higher. When commanded On engine oil pressure is lower. The purpose of this diagnostic is to isolate either a stuck on or stuck off engine oil pressure control solenoid.

The quart in 2K you are losing, do you add oil to get it back up to the proper level? Its not the AFM that's consuming oil, its either a leak or piston oil control rings that aren't doing their job anymore (didn't seat, stuck from carbon, etc.)

Here are the bulletins on P06DD from GM that shed a good bit of insight on the oil pump solenoid concerns:

PIP5555A P06DD Setting With Original Oil pump Or A Replacement oil Pump (nhtsa.gov)

MC-10165914-9999.pdf (nhtsa.gov)

PIP5308B SES Light P0521 P06DD And Low Oil Pressure (nhtsa.gov)

Jayselectricco · October 13, 2022

3 minutes ago, newdude said:

P06DD is oil pump solenoid control valve performance/stuck off.

The quart in 2K you are losing, do you add oil to get it back up to the proper level? Its not the AFM that's consuming oil, its either a leak or piston oil control rings that aren't doing their job anymore (didn't seat, stuck from carbon, etc.)

Here are the bulletins on P06DD from GM that shed a good bit of insight on the oil pump solenoid concerns:

PIP5555A P06DD Setting With Original Oil pump Or A Replacement oil Pump (nhtsa.gov)

MC-10165914-9999.pdf (nhtsa.gov)

PIP5308B SES Light P0521 P06DD And Low Oil Pressure (nhtsa.gov)

Well it wasn't stuck off in my case, because the code hasn't come back for me. I was just sharing my experience with others that have this code, and they were telling me that they change the oil and it goes away but comes back on right before the next oil change. You can prove that its not stuck off by watching the oil pressure at a hot idle. On the 4.3 the oil pressure will drop back to 20-30 psi when the 2 stage oil pump turns on and puts it in "low pressure mode." If it doesn't it never will drop below 40. Also if it is stuck off you would never be able to make the code go off and stay off for thousands of miles by just changing the oil. I guess the dirty oil could be making their "flakey" oil pump start to intermittently stick off when its close to their oil change.... the oil usage on my truck is more like a quart every 3k because I change the oil every 3k and notice that its about 1/3 of a quart low. Most people that I have talked to say their trucks use oil due to the AFM, at least the ones that I have talked to with my generations Silverado.

Grumpy Bear · October 15, 2022

On 10/12/2022 at 11:58 AM, customboss said:

But the 5w30 will drive a higher hydraulic pressure that's not needed and can change valve timing dynamically.

What? Okay a slave cylinder will move slowly when the oil is like -30F and viscosity is 60,000 cP. Pushing peanut butter instead of hot honey, but the difference of even 20 cSt at 212 F would not even be measurable. The difference between an SAE 20 min and an SAE 60 max. There is more difference between 100 F and 212 F. More difference between running an oil cooler maintaining 190 F and unregulated at 250 F. C'mon.....

Besides. Timing LIMITS are controlled by the mechanical RANGE and not how quick the fluid moves. Pressure isn't influenced by viscosity. A 1 cP cup of water will transmit the same PRESSURE as a steel rod. This isn't a system pushing fluid through a sub-fractional orifice. It's pumping oil through the Holland tunnel balance against a spring.

Bet I get the same hydraulic PRESSURE at -25F as I do at 125F air temp. Gezz, don't tell my brakes this. They will quit working. :crackup: Note viscosity vs temp of brake fluid below.