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.