NHTSA opens preliminary probe into more than 870,000 GM vehicles

[Roadglide16]

I don't know what y'all think this is going to do. GM is already reacting to the problem and trying to fix it. Losing money and angering your customers is not a good way to do business. Hopefully they'll ditch their DIE hires soon and the poor decisions that lead to these failures will get resolved quickly.

Any idea what GM is doing to try and fix this issue? Thanks!

 

[Scarey]

That’s the $80,000 question.

 

[DontTaseMeBro]

Seems from info I am finding is the front main bearing and the #1 and #2 rod bearings tend to be the more common failure on the 6.2l engines. This is most likely due to the front main bearing and rod bearings #1 and #2 being the last in the oil flow path or being furthest from the oil pump.

So yes, oversize lifter bores could be a contributing problem because the cam and lifters are supplied oil first and the front lower portion of the engine could be oil starved, or what about the 0W20 engine oil being a contributing factor as well? Could also be due to oil consumption and running the engines low on oil as well?

Add to that, the 2 stage oil pump. Not a lot of room for error. And if the conditions are just right, pretty ripe scenario for a kaboom.

 

[swathdiver]

Any idea what GM is doing to try and fix this issue? Thanks!

None. I do know a GM mechanic and will ask him and get back to you.

 

[Doubeleive]

Any idea what GM is doing to try and fix this issue? Thanks!

they are going to do whatever cost's them the least amount of money.
in the meantime you are at the mercy of whatever warranty you may have or pay out of pocket, in which case it would be wise to save any receipts.

 

[PPK_]

Add to that, the 2 stage oil pump. Not a lot of room for error. And if the conditions are just right, pretty ripe scenario for a kaboom.

The pressure we see on the dash is after the oil filter… but all the lifters and bearings are after it. It sure does look like the crankshaft front is what get oiled last… the oil pressure there is less than what you see on the dash. I imagine a plugged filter does not help either. It looks to me like a worn cam bearings could easily take oil pressure down enough for trouble in the mains/rods. Not good…

it sure does look like going to a 5w30 makes some sense as you will reduce lost pressure.. due to higher viscosity.. assuming enough oil is left to cool things..

 

[DontTaseMeBro]

The pressure we see on the dash is after the oil filter… but all the lifters and bearings are after it. It sure does look like the crankshaft front is what get oiled last… the oil pressure there is less than what you see on the dash. I imagine a plugged filter does not help either. It looks to me like a worn cam bearings could easily take oil pressure down enough for trouble in the mains/rods. Not good…

it sure does look like going to a 5w30 makes some sense as you will reduce lost pressure.. due to higher viscosity.. assuming enough oil is left to cool things..

Yup. I made that conclusion after the last oil change. 5W-30 from here on out.

 

[jfoj]

This is what I posted in the Engine and Drivetrain thread with the same title.

"From the diagrams it appears the oil pressure sensor is mounted on the rear of the DFM manifold that is on top of the engine. So in this case the sensor is at the beginning of the oil flow path which is typical of most engines, but with all the DFM gear and the 2 stage oil pump, it would have probably been wiser to have the oil pressure sensor at the end of the oiling path.

This is what happens when you take a basic 60+ year old design and just keep adding bits and pieces on it over the years.

For reference I was able to obtain oil pressure values using a more advanced scan tool.

Approximately 28 PSI warm idle in gear
Approximately 33 PSI warm idle in neutral
Approximately 46 PSI @ 75 MPH at approximately 1600 RPM

The oil pressure did appear to boost past the 1/2 way point on the dash gauge when passing and the RPMs were up. Hopefully I will be able to graph the oil pressure behavior so I can get a better idea how it is controlled."

Totally agree with the 5W30, went in after the 500 mile oil change. Just search Oil Wedge (see YouTube link below) and this along with the vane oil pump draining when the engine is shut off and the fact the slightly thicker oil will stay in the journals longer when the engine is turned off. Also disable the auto Stop/Start or turn it off each time you drive. TOO MANY dry or partially dry starts with 0W20 is NOT going to be helpful.

 

[jfoj]

A few other comments:

1. After a lot of searching about 6.2l engine failures, it became clear that the majority of what I was finding were failures with the front main bearing and/or the #1 and #2 rod bearings. #1 and #2 rod bearing failures are likely tied to the #1 main bearing failure/oil starvation. Yes there are other failures as well to include other main and rod bearings and the thrust bearing. But front main and rods #1 and #2 were far more common. I even found a few posts from dealer techs and one mentioned he had 5 front main bearing failures on the 6.2l engine.

2. If you tow with your 6.2l, there is NO WAY I would run 0W20 oil in the engine. Depending on the amount of weight you are towing, this can and will put a far greater load on the engine bearings as well as heat the oil up. This becomes a severe duty situation when towing more that 1000 lbs IMHO. And if you tow with the truck loaded with gear and people then any towing may be severe duty. The rear main bearing and thrust bearings can take more loading when towing. So I would be very concerned about 0W20 protection when towing.

3. Oil consumption will also be lower with 5W30 rather than 0W20. So if you are having oil consumption issues and are tired of always checking and worrying about the oil level, consider running 5W30 oil.

4. While the previous generation engines started to use 0W20 in the later years, it looks like the earlier documentation indicated either 10W30 or 5W30 oil. I have not really tracked what changed with the 2020 and earlier 6.2l engines other than AFM vs DFM, I need to check if the earlier AFM generation engines ran the 2 stage oil pump.

5. Keep in mind the DFM will not likely be active until the engine is warmed up and at least is Closed Loop fuel control operation, but I would also bet the DFM may not become active until a specific engine temperature. So the 0W portion of the oil is probably not as important for any DFM operation.

I am less on board about supplier quality issues with bearings and more about oil starvation. As for the valve lifter situation, maybe this was a supplier issue?? The valve lifter issue seems to have either been minimized or has totally been overshadowed due to the bearing/engine failures. I do not think bearing technology has changed significantly in the past few decades unless someone was trying to get lower friction bearings for fuel economy and foolishly changed the bearing design.

Not sure how many people actually contacted NHTSA, but searching online there are A LOT of failures. Even out of the failures, I am sure a good percentage of the owners never posted anything on forums or social media. Some may have said screw it and just worked out a trade and moved on. I hope the NHTSA staff starts to search for failures online, but this is a lot to ask from your average government employee. But maybe they will surprise all of us.

I hope there is a resolution to these bearing failures, but like anything GM will trade off what replacement engines cost is vs any fines and penalties they may incur if they suggest a change of oil type. I expect that GM will run all sorts of formulas and scenarios to come up with a failure percentage that the NHTSA can agree is acceptable and this will be the end of things. GM will not likely issue a "Recall" to replace engines IMHO, they will try to solve this with a few new pieces of paper and/or reprogram the OLM/OCI. But this does nothing for all of us that may have engines that have premature wear and are partially compromised at this point.

As the world burns!

 

[PPK_]

A few other comments:

1. After a lot of searching about 6.2l engine failures, it became clear that the majority of what I was finding were failures with the front main bearing and/or the #1 and #2 rod bearings. #1 and #2 rod bearing failures are likely tied to the #1 main bearing failure/oil starvation. Yes there are other failures as well to include other main and rod bearings and the thrust bearing. But front main and rods #1 and #2 were far more common. I even found a few posts from dealer techs and one mentioned he had 5 front main bearing failures on the 6.2l engine.

2. If you tow with your 6.2l, there is NO WAY I would run 0W20 oil in the engine. Depending on the amount of weight you are towing, this can and will put a far greater load on the engine bearings as well as heat the oil up. This becomes a severe duty situation when towing more that 1000 lbs IMHO. And if you tow with the truck loaded with gear and people then any towing may be severe duty. The rear main bearing and thrust bearings can take more loading when towing. So I would be very concerned about 0W20 protection when towing.

3. Oil consumption will also be lower with 5W30 rather than 0W20. So if you are having oil consumption issues and are tired of always checking and worrying about the oil level, consider running 5W30 oil.

4. While the previous generation engines started to use 0W20 in the later years, it looks like the earlier documentation indicated either 10W30 or 5W30 oil. I have not really tracked what changed with the 2020 and earlier 6.2l engines other than AFM vs DFM, I need to check if the earlier AFM generation engines ran the 2 stage oil pump.

5. Keep in mind the DFM will not likely be active until the engine is warmed up and at least is Closed Loop fuel control operation, but I would also bet the DFM may not become active until a specific engine temperature. So the 0W portion of the oil is probably not as important for any DFM operation.

I am less on board about supplier quality issues with bearings and more about oil starvation. As for the valve lifter situation, maybe this was a supplier issue?? The valve lifter issue seems to have either been minimized or has totally been overshadowed due to the bearing/engine failures. I do not think bearing technology has changed significantly in the past few decades unless someone was trying to get lower friction bearings for fuel economy and foolishly changed the bearing design.

Not sure how many people actually contacted NHTSA, but searching online there are A LOT of failures. Even out of the failures, I am sure a good percentage of the owners never posted anything on forums or social media. Some may have said screw it and just worked out a trade and moved on. I hope the NHTSA staff starts to search for failures online, but this is a lot to ask from your average government employee. But maybe they will surprise all of us.

I hope there is a resolution to these bearing failures, but like anything GM will trade off what replacement engines cost is vs any fines and penalties they may incur if they suggest a change of oil type. I expect that GM will run all sorts of formulas and scenarios to come up with a failure percentage that the NHTSA can agree is acceptable and this will be the end of things. GM will not likely issue a "Recall" to replace engines IMHO, they will try to solve this with a few new pieces of paper and/or reprogram the OLM/OCI. But this does nothing for all of us that may have engines that have premature wear and are partially compromised at this point.

As the world burns!

Basically,, the oil pump is too small. not great news... especially at a lower rpm. bummer.