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

[PPK_]

Suggest you do your homework and research. LPSI is not just on forced induction small displacement engines. The 6.2 barely runs over 1800 RPM under all but sprited conditions and maybe towing where the engine downshift or if the shift points are altered much in other driving mode.

LSPI is more a function of oil introduced into the cylinders, liquid fuel in the cylinder and higher cylinder pressures during lower RPM, high load considtions where the throttle is open over 30-40%. Also understand the vehicle being propelled is not a 3000 lb rice rocket, this engine is propelling a 6000 brick.

Coupled with running Regular grade fuel. While the spec sheet for the L87 indicated it runs on Regular fuel, this is not what the owners manuals indicate. They recommend Premium fuel.

So.. 89 or higher octane? Catch can? 5w30 oil.. carbyte dfm tool.. is this it?

 

[jfoj]

So.. 89 or higher octane? Catch can? 5w30 oil.. carbyte dfm tool.. is this it?

I wish I had the magic ball. Hopefully GM knows exactly why the 6.2l are failing at the rate they are.

But my take after a lot of research about the problems, I took the following approach.

91-93 Octane fuel, take the possibility of LSPI out of the equation due fuel as much as possible, yes it costs more, but if it saves the engine and inconvienance of a failure, it is worth it.

5W30 oil all day long, 0W20 was not chosen for engine lifespan, it was to check some box to get closer to the CAFE ratings needed for the manufacturer. Continue to use a Dexos oil as part of the Dexos forumaltion is to reduce some detergants as these are contibutors to LPSI. 5W30 likely has less pumping use of oil if the DFM is fuctioning in any form and less cylinder face wash down due to DI, so again less oil in the combustion chamber and also less overall oil consumption. Very few oils other than 0W20 and 5W30 oil have Dexos ratings. Less oil in the combustion chamber and less the the usual detergents mean less possiblity of LSPI.

Catch can to reduce oil and moisture being pulled into the intake path for LSPI concerns as well as reducing intake valve carbon build up. Less oil in the combustion chamber, the less chance for LPSI. I believe that added moisture in the combustion chamber can also add up to more carbonizing of the oil around the piston ring grooves.

I am running the Range DFM disabler. While some say it does not fully disable DFM during Decel with Fuel Cut Off it is better than nothing. Additionally this also disabled the Auto Stop/Start feature as well. I think the Auto Stop/Start feature adds to dryer engine starts with 0W20 oil, 5w30 likely holds an oil film on the bearing surfaces longer and better than 0W20. Again, I also think there may be some pumping action that pulls oil past the piston rings when the DFM is enabled causing more oil consumption/oil in the cylinders. Not hearing about as many bent push rods or lifter failures on the newer year engines, so not sure these are as big of a problem these days, but more people are also probably running DFM disabler devices as well.

Added a magnetic drain plug, my 2005 6.0l had this as standard, while is may help things it is also a good indicator for me to see what iron and steel fines are in the crankcase. It may help reduce very fine iron and steel fines from getting past the filter, but who knows. more of a tool for me to judge what is going on inside the engine.

FilterMag, 2 half moon strong magnets that slip on the filter, yes stupid expense, but again may help with iron and steel fines and also allows me to see what is inside the filter when cut open.

Oil change, oil change, oil change. Changed at 500 miles, then at 3000 miles and will be changeing every 3000-4000 mile interval or about 50% on the OLM. Also running 9 qts with filter and prefilling oil filter before installation. Some may disagree, but this is what I am doing. Additonal 1 quart keeps oil level to where I found vehicle when delivered and allows for less impact on fuel dilution even with short interval oil changes.

Also performing oil anlysis on every change. More to track fuel contamination and potention early engine failure to maybe help determine if I get rid of vehicle before catastrophic failure?

Considering running Techron Fuel Additive every 2nd fill up as this has been suggested to help with ring groove carbon build up.

I may be over thinking and over doing things, but I really do not want an engine failure. The bulk of my driving once I start the engines is between 2-6 hours and usually highway driving. For example, I just returned home early this morning, 2:30 am after a 2 1/2 hour drive. Fine if the engine fails when the roads are lightly traveled hopefully I can get on the shoulder or somewhere safe, but not fine being stranded at 2:00 am where is it hard to see and to get someone to respond in BFE to tow my truck and then to get home at that hour.

We will see how things turn out, really only 2 possible outcomes.

1. My vehicle has an engine failure before 7,500 miles or somewhere between 25,000-35,000 miles,

2. I do not suffer an engine failure during my ownership of the vehicle.

I prefer what is behind door #2!

I am sure there may be some comments and other ideas.

 

[RG23RST]

Suggest you do your homework and research. LPSI is not just on forced induction small displacement engines. The 6.2 barely runs over 1800 RPM under all but sprited conditions and maybe towing where the engine downshift or if the shift points are altered much in other driving mode.

LSPI is more a function of oil introduced into the cylinders, liquid fuel in the cylinder and higher cylinder pressures during lower RPM, high load considtions where the throttle is open over 30-40%. Also understand the vehicle being propelled is not a 3000 lb rice rocket, this engine is propelling a 6000 brick.

Coupled with running Regular grade fuel. While the spec sheet for the L87 indicated it runs on Regular fuel, this is not what the owners manuals indicate. They recommend Premium fuel.

You may want to present these findings of yours to the two OEMs I've worked for. It would be news to them as it's counter to every bit of training I've had going back a decade. You can also admit you don't know what you're talking about.

Naturally aspirated engines do not have a high enough dynamic compression ratio to introduce LSPI. They also don't have charge air coolers pooling oil vapor and pulling it into the inlet manifold. LSPI got a lot of attention around a decade ago and then the problem was solved in short order. The fix was partly engine oil and partly controlling charge air temperature to keep the vapor and condensation from pooling.

 

[RG23RST]

So.. 89 or higher octane? Catch can? 5w30 oil.. carbyte dfm tool.. is this it?

You cannot out-maintenance defective bearings. That is the problem causing the catastrophic failure.

Lifter bore sizing, valve spring heat treat, etc were all separate issues that did not present as sudden engine failure.

 

[PPK_]

I wish I had the magic ball. Hopefully GM knows exactly why the 6.2l are failing at the rate they are.

But my take after a lot of research about the problems, I took the following approach.

91-93 Octane fuel, take the possibility of LSPI out of the equation due fuel as much as possible, yes it costs more, but if it saves the engine and inconvienance of a failure, it is worth it.

5W30 oil all day long, 0W20 was not chosen for engine lifespan, it was to check some box to get closer to the CAFE ratings needed for the manufacturer. Continue to use a Dexos oil as part of the Dexos forumaltion is to reduce some detergants as these are contibutors to LPSI. 5W30 likely has less pumping use of oil if the DFM is fuctioning in any form and less cylinder face wash down due to DI, so again less oil in the combustion chamber and also less overall oil consumption. Very few oils other than 0W20 and 5W30 oil have Dexos ratings. Less oil in the combustion chamber and less the the usual detergents mean less possiblity of LSPI.

Catch can to reduce oil and moisture being pulled into the intake path for LSPI concerns as well as reducing intake valve carbon build up. Less oil in the combustion chamber, the less chance for LPSI. I believe that added moisture in the combustion chamber can also add up to more carbonizing of the oil around the piston ring grooves.

I am running the Range DFM disabler. While some say it does not fully disable DFM during Decel with Fuel Cut Off it is better than nothing. Additionally this also disabled the Auto Stop/Start feature as well. I think the Auto Stop/Start feature adds to dryer engine starts with 0W20 oil, 5w30 likely holds an oil film on the bearing surfaces longer and better than 0W20. Again, I also think there may be some pumping action that pulls oil past the piston rings when the DFM is enabled causing more oil consumption/oil in the cylinders. Not hearing about as many bent push rods or lifter failures on the newer year engines, so not sure these are as big of a problem these days, but more people are also probably running DFM disabler devices as well.

Added a magnetic drain plug, my 2005 6.0l had this as standard, while is may help things it is also a good indicator for me to see what iron and steel fines are in the crankcase. It may help reduce very fine iron and steel fines from getting past the filter, but who knows. more of a tool for me to judge what is going on inside the engine.

FilterMag, 2 half moon strong magnets that slip on the filter, yes stupid expense, but again may help with iron and steel fines and also allows me to see what is inside the filter when cut open.

Oil change, oil change, oil change. Changed at 500 miles, then at 3000 miles and will be changeing every 3000-4000 mile interval or about 50% on the OLM. Also running 9 qts with filter and prefilling oil filter before installation. Some may disagree, but this is what I am doing. Additonal 1 quart keeps oil level to where I found vehicle when delivered and allows for less impact on fuel dilution even with short interval oil changes.

Also performing oil anlysis on every change. More to track fuel contamination and potention early engine failure to maybe help determine if I get rid of vehicle before catastrophic failure?

Considering running Techron Fuel Additive every 2nd fill up as this has been suggested to help with ring groove carbon build up.

I may be over thinking and over doing things, but I really do not want an engine failure. The bulk of my driving once I start the engines is between 2-6 hours and usually highway driving. For example, I just returned home early this morning, 2:30 am after a 2 1/2 hour drive. Fine if the engine fails when the roads are lightly traveled hopefully I can get on the shoulder or somewhere safe, but not fine being stranded at 2:00 am where is it hard to see and to get someone to respond in BFE to tow my truck and then to get home at that hour.

We will see how things turn out, really only 2 possible outcomes.

1. My vehicle has an engine failure before 7,500 miles or somewhere between 25,000-35,000 miles,

2. I do not suffer an engine failure during my ownership of the vehicle.

I prefer what is behind door #2!

I am sure there may be some comments and other ideas.

I just did a warranty on mine to 72/72. $1472 with 250 deduct.. gmep.. i have been trading cars a lot.. but.. these gm v8s are not nearly what they were. Bummer.

 

[jfoj]

You may want to present these findings of yours to the two OEMs I've worked for. It would be news to them as it's counter to every bit of training I've had going back a decade. You can also admit you don't know what you're talking about.

Naturally aspirated engines do not have a high enough dynamic compression ratio to introduce LSPI. They also don't have charge air coolers pooling oil vapor and pulling it into the inlet manifold. LSPI got a lot of attention around a decade ago and then the problem was solved in short order. The fix was partly engine oil and partly controlling charge air temperature to keep the vapor and condensation from pooling.

See this is your shortcoming, you were focused on this issue around a decade ago, today is a different time. Assume you were likely focused on smaller displacement turbocharged engines? Yes these engines have more of a tendancy for LSPI, but this issue is by no means dead and gone today. Forced induction engines are FAR MORE prone to LSPI and for LSPI research and detection, forced induction engines are typically used because the conditions for LSPI are easier to produce in the Lab or a controlled environment then when compared to NA engines.

The other problem is the traditional Piezo knock sensor does not do a good job detection or fully detection LSPI due to the behavior of LSPI. So what happens if LSPI can and will occur if the conditions are favorible and at the end of the day the engine electronics may not pick up or adjust fully to try and reduce LSPI. So LSPI is not always easy to detect and may not even be heard inside the drivers compartment under certain conditions.

LSPI does not need a specific compression ratio or cylinder charge pressure to occur. Obviously the higher the compression, the higher the cylinder charge pressure and the higher the air charge temperature, the more likely LSPI is to occur.

LSPI occurs in more covert ways during the actual combusion process. Additionally have you read and seen all the discussion of excessive oil consumption is occuring on these NA engines? As low as a quart per 1000-1500 miles, people indicating they are having to add 2+ quarts of oil between 7500-8000 OCI. Low oil lights coming on (usually at around 2 quarts low) before the OCI is expired. Where do you think all of this oil is going?

Fuel dilution of the engine oil is partially the cause of some of the excess oil consumption as are driving conditions, the DFM system and the lower viscosity engine oils. Add to this the fact that these V8 engines operate for the most part in the 1200-1700 range under heavy engine loads, especially the 6.2l and in a typicall chassis that weighs 6000 lbs. My 6.2l Yukon vary rarely downshifts on the the highway, just torques through most hills and grades in 10th gear. The primary cause of LSPI is oil and liquid fuel. These 2 things added into the combustion process cause all sorts of unexpected behaviors. The reduction/elimination if the engine oils as a detergent also help reduce the occurances of LPSI, this is one of the things the Dexos oil spec addressed.

I think engine bearings may be getting the bulk of the blame here, there may be some problems, but I cannot belive if bearings were the primary problem, this issue would be ongoing after 6+ years of production. I am seeing oil starvation partial due to engines oiling system design (oil path and 6.2l 2 stage oil pump), engines being run low 2+ quarts on oil due to oil consumption, extended oil change intervals with fuel diluted oil along with seasonal fuels and seasonal driving conditions adding to the fuel dilution problem as well. Fuel diluted engine oil when the engine is low is also a bad thing. Last I checked, lubricating with a solvent does not end so well under high and very dynamic engine load conditions.

And of course LSPI or what some in the industry have coined the term as Mega Knock. This does in fact occur in Naturally Aspriated engines. Mega Knock will not be kind to pistons, piston rings and bearings. The 6.2 also having the 2 stage oil pump and running 0W20 will not likely end well, especially operating with low engine oil levels.

I do not expect there will ever be an "Engine" recall and wholesale engine replacement program for the 5.3l or 6.2l in these trucks, but I could be wrong. I expect at best case, if the numbers add up, there will be a software fix for a set of hardware/operational /maintenace problems. Chances are GM will tweak the OLM, might change some other engine parameters, but this will be trickey due to EPA/CAFE/Fuel Economy requirements, as anything that would be changed with the ECM tune would likely have an impact of fuel ecomony and emissions so this will not happen without a lot of politics. I could easily see the 6.2l 2nd stage oil pump conditions be tweaked, they might be able to skate the EPA/CAFE/Fuel Economy standards a bit with the oil pump programming, but who knows. Everything and anything that impacts EPA/CAFE/Fuel Economy rarely happens. I know this first hand from a number of years with a major auto manufacturer.

 

[jfoj]

I just did a warranty on mine to 72/72. $1472 with 250 deduct.. gmep.. i have been trading cars a lot.. but.. these gm v8s are not nearly what they were. Bummer.

I agree, engine technology has advanced and we are getting far better power density and fuel economy, but at the cost of reliabilty and engine lifespan. I am guessing these engines with the DFM and variable cam timing systems probably have close to 50 or more additional mechanical parts, sensors and controls that clearly do not increase the engine reliability or lifespan and will cost the owner WAY more when a problem does occur. Additionally I think the maintenace intervals have actually gone backwards, but the marketing is telling you otherwise. I still compare everything to my 2005 6.0L gold standard! 275,000 mile and counting, still drive it daily. If owes me NOTHING, every mile I put on it costs me very little. I am actually thinking about taking the drained/used oil from the 2024 6.2l and running it in my 2005, again, this will reduce my cost and 9 qts of used motor oil that only has 3000-4000 miles on it is just what my 2005 would get along good with.

I would not run the OLM more than 50% on these newer DI engines for a multitude of reasons. I would love to see how many owners REALLY plan on running 15,000 mile oil changes on a current generation DI engine. For the cost of these vehicles and the down time for repairs, it is reall worth not changing the oil more frequently?

One thing I forgot to mentions, with running 5W30, no Auto Stop/Start and at least the Range DFM disabler, my Average Fuel Econmy for close to 4000 miles under a variety of driving conditions is right at 17.4 MPG. For straight highway driving I am doing slightly over 18 MPG, but if I ease up on the right foot, I have clocked multiple 50 mile averages of just over 20 MPG.

So lets talk about all the things I have countered on the vehicle and how it may have impacted the overall fuel economy. If I was running the truck as delivered from the dealer with the original oil still in the engine, what would I be getting 22+ MPG on a regular basis?? I really do not think so for a 6000 brick that has shutters in the grille! I do not see the Auto Stop/Start doing anything more than putting wear and tear on the engine and starting system. Sure the Auto Stop/Start system will help the city/town ecomomy quite a bit because while stopping in traffic or at a traffic light and the engine idling you go from MPG to HPG! HPG effectively KILL the MPG in town. I tend to put the transmission in Neutral to take the loading off the transmission and engine at longer traffic lights and so forth, not for economy but more for wear and tear. The transmisson engages very smoothly so I am not so worried about in and out of gear so much. I do this about 30% of the time are major intersections.

The DFM doing nothing more than agrevating the driver and maybe contributing to at most 0.5-1.0 MPG improvement.

0W20 for fuel economy, this is probably mouse nuts. I would rather protect the engine, then save $0.50 cents a fill up.

At the end of the day I did not buy a 6000 LONG Brick for fuel economy anyway!

We will see when I have to report in that my 6.2l locked up.

 

[jerry455]

I know the Eco Boost Ford engines are having the LSPI problem. I have been running 0W30 Mobil 1 and my 2021 High Country Suburban weighs 5,370 pounds with me in it. I always run premium fuel in my 6.2 and all the vehicles in our house use premium, so it is not even a concern to use it. I don't think the oil life system goes past 7,500 miles. GM lowered that several years ago.

 

[jfoj]

I know the Eco Boost Ford engines are having the LSPI problem. I have been running 0W30 Mobil 1 and my 2021 High Country Suburban weighs 5,370 pounds with me in it. I always run premium fuel in my 6.2 and all the vehicles in our house use premium, so it is not even a concern to use it. I don't think the oil life system goes past 7,500 miles. GM lowered that several years ago.

Wise running something other than 0W20.

I did check and was surprised that the Mobil 1 0W30 was Dexos approved, not many oils outside of 0W20 and 5W30 are Dexos approved oils.

I chose 5W30 for as it has not failed my 6.0l in 275,000 miles and I have not been overly dilligent in OCI, but then again, the 6.0l is different technology overall, non DI, non AFM/DFM, non variable cam timing, lower compression. I put anything that will burn in fuel tank of my 2005. It just keeps running. The difference between 0W and 5W is this is more about the base stock the oil is forumlated from and I am not worried about anything with the DFM because even if it was not bypassed, it will not function until the engine is significantly warmed up.

A few quesitons:

1. How many miles on your 2021?
2. Is your 2021 one of the models that did not have DFM enabled due to chip shortages?
3. Any oil useage with 0W30 between oil changes?
4. What is the approximate oil pressure showing on your 2021, I know you will probably be guessing somewhat due to the dash gauge. If you have a more advanced scan tool, they can usually read the oil pressure transducer in 1 PSI incriments.

 

[blanchard7684]

See this is your shortcoming, you were focused on this issue around a decade ago, today is a different time. Assume you were likely focused on smaller displacement turbocharged engines? Yes these engines have more of a tendancy for LSPI, but this issue is by no means dead and gone today. Forced induction engines are FAR MORE prone to LSPI and for LSPI research and detection, forced induction engines are typically used because the conditions for LSPI are easier to produce in the Lab or a controlled environment then when compared to NA engines.

The other problem is the traditional Piezo knock sensor does not do a good job detection or fully detection LSPI due to the behavior of LSPI. So what happens if LSPI can and will occur if the conditions are favorible and at the end of the day the engine electronics may not pick up or adjust fully to try and reduce LSPI. So LSPI is not always easy to detect and may not even be heard inside the drivers compartment under certain conditions.

LSPI does not need a specific compression ratio or cylinder charge pressure to occur. Obviously the higher the compression, the higher the cylinder charge pressure and the higher the air charge temperature, the more likely LSPI is to occur.

LSPI occurs in more covert ways during the actual combusion process.

Case in point with a gen 5 6.2

Investigating Oil Composition, Direct Injection, & Low-Speed Knock

The discovery of low-speed knock events exclusive to direct injection led EFI University and Lake Speed, Jr. of Driven Racing Oil to examine the cause.

www.enginelabs.com

In general bore size , combustion chamber design, ignition timing , and afr are foundational drivers of pre-ignition because they determine the pace of the flame front.

Low engine speeds and low throttle positions are low VE which require higher ignition timing. The pace of the flame front is relatively slow.

A large and fast change in throttle position can trigger a pre ignition event… even with low dynamic compression. This is a rapid change from low ve to moderate or high ve with ignition timing still at a fairly advanced stage. The flame front is a bit too slow and ignition occurs in advance of it leading to pre ignition.

Modern engine controls have done a good job of managing these lspi events…. But it is always an issue that requires consideration for obvious reasons.

Throw in fuel dilution of the oil and you can get a situation like in the case above, where the system detects the lspi event but can’t do anything about it.

 

[WalleyeMikeIII]

Case in point with a gen 5 6.2

Investigating Oil Composition, Direct Injection, & Low-Speed Knock

The discovery of low-speed knock events exclusive to direct injection led EFI University and Lake Speed, Jr. of Driven Racing Oil to examine the cause.

www.enginelabs.com

In general bore size , combustion chamber design, ignition timing , and afr are foundational drivers of pre-ignition because they determine the pace of the flame front.

Low engine speeds and low throttle positions are low VE which require higher ignition timing. The pace of the flame front is relatively slow.

A large and fast change in throttle position can trigger a pre ignition event… even with low dynamic compression. This is a rapid change from low ve to moderate or high ve with ignition timing still at a fairly advanced stage. The flame front is a bit too slow and ignition occurs in advance of it leading to pre ignition.

Modern engine controls have done a good job of managing these lspi events…. But it is always an issue that requires consideration for obvious reasons.

Throw in fuel dilution of the oil and you can get a situation like in the case above, where the system detects the lspi event but can’t do anything about it.

That article is some fascinating stuff; and is dated in 2017. I would expect the conclusions have been reached by now. And I would expect the Big 3 (and others) were and are aware of it. So...did they react? Would be interesting to see the actual conclusions of that research...I will search for a follow up article when I get time. Thanks for sharing.

 

[jfoj]

I think like anything there was a funding issue that impacted carry on testing.

Not condemning any of these guys for their knowlege and/or testing, BUT they really did not perform "Real World" testing and "Real World" data gathering.

These motors in daily use rarely ever see anything above 2500 RPM, there testing did not even start until above this RPM. They need to test, dyno and load the engines how the vehicles are driven on a daily basis to really get the real world info.

Driving my truck, the engine never gets over 1800 RPM on the highway unless I really need to pass and get around traffic. The engine typically runs around 1600 RPM for the majority of my highway drives and I have started to monitor the Calculated Engine Load % and I was SHOCKED at least with the 6.2l the engine tends to operate often between 50% and 90% calculated load without ever downshifting under most conditions. This in terms is literally "Low Speed" and High Loading conditions that need to be tested and replicated in the lab enviroment.

The other thing that needs to happen during this style of testing is to pre-contaminated the engine oil with fuel to simulate what happens in the real world. Baseline the engine with clean/fresh oil, then start to contaminate the engine oil with fuel and possibly water and then see what happens. There is enough data from oil sampling (Speed Diagnostics is Lake Speeds Oil Analysis Company) they know what the typical and higher range of fuel contamination actually is based on sampling. Then they probably need to push even further with fuel contamination because there are times where the fuel levels are probably higher before some of the fuel is actually "cooked" off.

 

[blanchard7684]

Driving my truck, the engine never gets over 1800 RPM on the highway unless I really need to pass and get around traffic. The engine typically runs around 1600 RPM for the majority of my highway drives and I have started to monitor the Calculated Engine Load % and I was SHOCKED at least with the 6.2l the engine tends to operate often between 50% and 90% calculated load without ever downshifting under most conditions. This in terms is literally "Low Speed" and High Loading conditions that need to be tested and replicated in the lab enviroment.

Damn. The 5.3 in my suburban can’t sniff that. 1600 rpm and up to 90% load is nuts.

 

[KMeloney]

Anyone have any sense for whether the 6.2 failures occur only at highway speeds? Most (if not all) of the stories I've read about have occurred on the highway, presumably at or over 65 mph. I haven't read about a failure occurring in town/in stop-and-go traffic.

 

[jfoj]

Anyone have any sense for whether the 6.2 failures occur only at highway speeds? Most (if not all) of the stories I've read about have occurred on the highway, presumably at or over 65 mph. I haven't read about a failure occurring in town/in stop-and-go traffic.

Seems to be a number of failure modes.

I posted a YouTube link earlier in the thread of a Cadillac Escalade that failed at the dealer with 4 miles on the engine. Broken connecting rod. This was clearly a wrist pin that walked sideways and jammed the piston in the cylinder. The rod bearing was fine. So this was clearly not an oiling problem.

Most of the highway failures IMHO and based my research have been bearing failures of some sort. Maybe we are only hearing about engines failing on the highway because is can be rather dangerous depending on the situation. Maybe any pre-failures where the engine is noisy are taken to shops before the engine siezes. Maybe there are engines siezing when in town or while idling that nobody is really speaking out about? But given the loading the 6.2l can put on rod bearings due to the high torque at lower RPM's I can see a lot of failures on the highway.

I think most of the bearing failures are oil related:

1. Lack of oil, oil consumption causing the oil level to drop and the low oil light does not come on until the oil is 2+ quarts low. If you own a 6.2l you NEED to check the oil at every other fill up. The stupid dipstick also will not have oil showing if the engine is 1 quart low. You should fill the crankcase up to the dipstick shows oil to the TOP of the hash marks, even slightly above is fine. I run 9 qts in my engine at oil change with filter, the engine really needs somewhere between 8.5-8.75 qts at oil change even though documents indicate 8.0 qts with filter.

2. 6.2 has a 2 stage oil pump, I question the pressure/volume available during high loads at highway speeds with 0W20 engine oil. The 5.3l has the same basic oil pump, but not the ECM 2 stage presure control. I have it from a few sources that the 5.3l runs close to 60 PSI at highway cruise, my 6.2l runs at 45-46 PSI at about 75 MPH/1600 RPM as measured with an advanced scan tool that interogates the oil pressure transducer. This pretty much matched the area the oil pressure gauge as shown on the dash, but with no numbers other than 0 and 120 it is hard to tell based on how far to the left of the center mark!

3. Fuel contamination in the oil either by itself and or oil that is contamined with fuel but it 1-2 quarts low on a regular basis.

4. Higher mileage failures are more likely due to long term exposure to fuel contaminated oil, low oil levels, long OCI's, causing bearing damage due to the 3 above issues and/or LSPI bearing damage.

5. So far I have seen 3 typical failures, but it would nice to have a wider sampling of failures.

A. Front main bearing failure often coupled with #1 and #2 rod bearing failures. These tend to be early failures, often under 10,000 miles, but not always. IMHO clearly oil starvation, oil quality issues. The accessory drive belts may load the crank snout a bit and without enough oil/oil pressure/oil volume, lower viscosity oil due to fuel contamination, this area is the dead last path on the engine oil flow. Maybe the talk about oversize lifter bores factors into this, I could see how it could and would, but we do not have a good idea of how many engines and what timeframe this could have been an issue, sure there was a bulletin or a number of bulletins because they kept extending the window for oversize lifter bores. And are these engine cores being returned and if the lifter bores are oversized, what is being done to address these before the same engine block is rebuilt and sent out? Are they scrapping these engine block or sleveing the lifter bores?

2. Thrust bearing failures. Not sure if this is just the thrust portion of the center bearing or the entire center bearing is failing. Possibly agrevated by towing? But again, oil condition, lack of oil or oil contamination are the first obvious concerns.

3. Other rod bearing failures, most likely oil, lack of oil or oil contamination are the first obvious concerns. Could also be due to piston clearance issues, piston pin walking causing bearing to crank interferance leading to premature bearing failure? LSPI? Could be possible quality issues with bearings, but I would expect to see a much larger amount of failures if this is 100% a bearing quality problems.

4. Not sure I have seen too many main bearing issues other than the #1 and the thrust bearing. Maybe they are out there and I just have not seen them.

5. It almost seems that the DFM lifter issue is scarce now. Maybe with all the premature bearing failures, the lifters have not had a chance to get the hours and miles on them to fail? Maybe they have made improvements with the lifters?

I still think the number of reported cases that have been reported to the NHTSA are low in compared to the number of overall failures. If someone has a failure, even if it is not at highway speeds, please report to the NHTSA so they have a better idea of the number of failures.

Drive defensively and make sure you have a way to the shoulder if you experience a failure. I hate when I get boxed in traffic or have a construction area where there are limited or no shoulders these days! I have actually altered by driving style to expect and deal with a siezed engine while on the highway these days. Not a fun way to drive and to have this nagging in the back of your mind. But as I say, it is what it is. I just do not need the wife and family in the car if there is a catastrohic failure! If that happens a Toyota minivan will be in my future.

 

[WalleyeMikeIII]

1. Lack of oil, oil consumption causing the oil level to drop and the low oil light does not come on until the oil is 2+ quarts low. If you own a 6.2l you NEED to check the oil at every other fill up. The stupid dipstick also will not have oil showing if the engine is 1 quart low. You should fill the crankcase up to the dipstick shows oil to the TOP of the hash marks, even slightly above is fine. I run 9 qts in my engine at oil change with filter, the engine really needs somewhere between 8.5-8.75 qts at oil change even though documents indicate 8.0 qts with filter.

Had to chuckle at this...my opinion is if you own any internal combustion engine you NEED to check the oil at EVERY fill up...been this way since I started being around engines...

I still think the number of reported cases that have been reported to the NHTSA are low in compared to the number of overall failures. If someone has a failure, even if it is not at highway speeds, please report to the NHTSA so they have a better idea of the number of failures.

I'd expect the NHTSA get that info from GM as part of the investigation; GM said they were cooperating w/ the probe. I would think the first set of data asked for would be the number of 6.2L shipped, and the list of the warranty replacements, the reason for replace, and any data on the failure analysis. Along w/ the serial numbers of the failed engines, date, time, and place of manufacture...

 

[jfoj]

Interesting, I already posted about this engine previously, but the comment about the 2025 units are "shipping with a new engine assembly" and should not be susceotable to the same issues.

I would love to know where this info came from for the article and if GM really knows what i going on and has not fessed up. Of is the BS line to get the sales on the 2025 going.

 

[jfoj]

Had to chuckle at this...my opinion is if you own any internal combustion engine you NEED to check the oil at EVERY fill up...been this way since I started being around engines...

Agree, but we have become conditioned to less oil leaks and oil consumption up until DI became prevalent. Then with the addition of low oil lights over 25 years ago, many people do not even open the hood of their vehicles.

Top this of with the disappearing dipsticks on many engines!!! The stupid low oil light on engines without dipsticks does not usually come on until the engine is over 1 qt low, sometimes closer to 2 quarts low!

In addtion to verifying the engine oil level, I use the dipstick to monitor the engine oil color and smell if for fuel contaminaiton. So for me the dipstick has 3 purposes, not just to verify the engine oil level.

But I am even guilty of sometimes ignore the wife's car. I try to confiscate it from her at least once a month to drive it, check the tires, fluids, fill up the fuel tank and vacuum and wash it. Many times I find things my wife did not pick up on the way the car was running or a new noise she did not hear.

Unfortunately too many vehicles and engines die a sad death due to neglect.

Dipsticks are for dipsticks, you need to use it if you have one!!!

 

[jerry455]

My Suburban has almost 81,00 miles and has never had any engine work done, it has DFM and Auto Stop. It uses very little oil, maybe half a quart over 5,000-6,000 miles. The oil pressrue at idle is around 30 psi and rises rapidly with RPM. I don't have a scanner, that is on my shopping list. I know the Global B architecture uses the MDI 2 but I want to find an aftermarket scanner because when I retire, I won't have access to that or Service Information.

 

[jfoj]

My Suburban has almost 81,00 miles and has never had any engine work done, it has DFM and Auto Stop. It uses very little oil, maybe half a quart over 5,000-6,000 miles. The oil pressrue at idle is around 30 psi and rises rapidly with RPM. I don't have a scanner, that is on my shopping list. I know the Global B architecture uses the MDI 2 but I want to find an aftermarket scanner because when I retire, I won't have access to that or Service Information.

Asssume you have the 6.2l engine?
What year is your Suburban?
What oil do you run in the engine?
Assume you change the oil between 5000-6000 miles or do you follow the OLM to 0%?

I am trying to get context for anyone reporting in.