FE Power Forums
FE Power Forums => Non-FE Discussion Forum => Topic started by: philminotti on April 16, 2025, 08:41:25 AM
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The 2019+ general motors L87 6.2L V8 has been having some very well publicized issues, and may involve a rather large recall. One of the issues has been lifter failure secondary to the AFM (active fuel management) cylinder deactivation feature. This problem has been around since the previous generation of the engine and many people deactivate the AFM function and have no issues. My 2017 Callaway Silverado with a 6.2 has AFM deactivated and I've had no issues in 80K miles.
The problem I'm most curious about with regard to the newer L87 is the reported catastrophic rod bearing failures. I'm sure OEM rod bearings are what they are, so it's unlikely to be a bearing material issue, correct? I suppose the most logical explanation for rod bearing failure would be an oiling issue. That being said, it's hard to imagine an egregious design mistake being made with regard to a fairly simple oiling system. Does anyone have any thoughts?
I was hoping to replace my Callaway with another one, but I'm not going near that engine for now. >:(
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Rod bearing failures are always a treat to get to the bottom of because the failure mode is so rapid and destructive, rarely is there any good evidence left behind to help determine what the problem was or the root cause. Some of the failure modes that I have seen analyzing warranty engines at work are due to the following.
1. Contaminated / Dirty / Old / Overheated Oil. Oil with coolant, fuel, dirt, etc can take out rod bearings quite quickly. Navistar, Ford (6.OH-No!), and CAT engines from the 2000's and 20-teens that used EGR extensively to meet emissions are particularly prone to this. EGR cooler develops an internal coolant leak, and all the sudden your engine is trying to lubricate with the green stuff. I have also seen a bunch of rod bearing failures in air cooled engines due to oil overheating. When I was at a small engine manufacturer, the life span of the rod bearing was measured in minutes once the oil hit 350 deg. F.
2. Machining Quality. Everything from surface finish, journal roundness, corner radius all can affect the lifespan of the rod bearing, and it doesn't take much of a deviation or miss to shorten the life span from 100,000's of miles to 100's of miles.
3. Engine (casting) Contamination - See recent Toyota Tundra recall
4. Crankshaft design / flex. If the crank flexes more than intended or designed, bearing failure can result. Typically this is more of a main bearing related problem, but it can lead to rod bearing damage as well. PACCAR 13L engines are known to experience more crank flex than intended and this will lead to failed bearings.
5. Rod Bolt Quality. About 3 years ago, we started seeing a dramatic rise in rod bearing failures on Navistar I-Series reman engines. Turned out, the rod bolt manufacturer (Navistar chosen and vetted supplier) had changed their process and the bolts were softer and did not have the designed tensile strength. Bolts would stretch and lose clamp load on the cap, and the bearing would spin. We discovered the problem by doing an extensive statistical study on our DC tool data (torque and angle) from assembly. The failure rate was only 3 to 5% of engines, so it was difficult to catch, but there was a statistical change in the data. The bolts were close to being correct (a measured sample would often meet the engineering print and specs), and they would even torque, yield, and stretch properly during assembly, but would fail within 10,000 miles. We went down a number of rabbit holes before we figured out the root cause on this one. Navistar ended up recalling all the rod bolts at their dealers and assembly facilities.
6. Bearing Material or Quality. Doesn't take much of a change at the supplier to cause problems in the engine.
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Thank you for your comprehensive answer.
Phil
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I’m also finding that everybody thinks changing your oil every 7500 miles when the change oil light comes on is ok. I put 4000 miles on customers oil stickers even when using synthetic and personally I use synthetic and still change every 3000 or pretty close to it. I know oils are better but oil is also a cleaner and after 5000 miles or so I don’t think it’s better than regular oil at that mileage. JMO.
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I’m also finding that everybody thinks changing your oil every 7500 miles when the change oil light comes on is ok. I put 4000 miles on customers oil stickers even when using synthetic and personally I use synthetic and still change every 3000 or pretty close to it. I know oils are better but oil is also a cleaner and after 5000 miles or so I don’t think it’s better than regular oil at that mileage. JMO.
THIS!!! Everybody seems to be on the extended oil change wagon these days. Combine this trend with more power from turbocharging / direct injection and you've got rod bearing failures across several manufacturers. Today's thin oil is not helping either. Smart people are changing their oil more often, and evidence suggests they are experiencing far fewer problems.
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No Doubt!!! I have been working with a CAT dealer that has been having problems with its rental fleet of large air compressors (540 HP 15L C15 engines in each compressor). They have been changing oil at the bare minimum interval of 500 hrs (and sometimes after more hours than that), but there have been a large number of front and rear main seal leaks and turbo bearing failures. CAT Engineering recommends changes more frequently if used in "extreme" environments, and these units are often placed in shipyards to support sandblasting operations, so salt air and silica dust definitely qualify for an extreme use environment. Add in the units being equipped with the "smaller" 38 Quart truck pan vs the 76 Quart industrial pan and this all adds up to engines going down on a frequent basis, which is very expensive for the rental fleet manager. Convincing them to up the maintenance frequency has been a challenge, despite the fact that a rebuild for one these engines can cost up to $50K.
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Makes me remember how well the big Luberfiner filters worked. In that case, are they not taking samples and getting them tested? It's a large cost to change that much oil at closer intervals, but how many more expensive failures does it take for them to change their policy?
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I’m also finding that everybody thinks changing your oil every 7500 miles when the change oil light comes on is ok. I put 4000 miles on customers oil stickers even when using synthetic and personally I use synthetic and still change every 3000 or pretty close to it. I know oils are better but oil is also a cleaner and after 5000 miles or so I don’t think it’s better than regular oil at that mileage. JMO.
Have to agree with Joe. Oil is much cheaper than major engine repairs! I was a Toyota dealership mechanic for the last 23 years before I retired, and I seen "recommended" oil change intervals changed from 6000 km (4000 miles), to 8000 km (5000 miles), 12000 km (7500 miles), and by the time I retired, up to 16000 km (10000 miles), and the engine oils had gotten as light as 0W-16! On top of that, oil consumption with such thin oils is quite common, at Toyota, up to 1 quart per 1000 km (600 miles), is considered acceptable. Considering many of these engines only hold 4 quarts, a "healthy" engine could be low enough to cause serious engine damage, long before the vehicle was even 1/2 to being due for an oil change. On my F350, with a V10,(Mobil 1 10/30 synthetic) and my 59 with a 428 CJ (Brad Penn 10/30 semi synthetic), I replace the oil and filters in the spring, regardless of mileage, usually 1500 miles or less. On our daily drivers, I have changed the oil and filters at 6000 km (4000 miles), or sooner. My wifes Corolla has 366,000 km (228,000 miles), and my 2010 Ranger has 214,000 km (133,000 miles), and both are running fantastic, and other than a blown head gasket on the Toyota 4 1/2 years ago, neither engine has been touched.
I know the Chevy LS engines with AFM/cylinder deactivation are well know to have cam and lifter failures, usually costing around $4000-$5000 Dollars to repair. (The later MoPar Hemis have similar problems, so personally, I would never buy a vehicle equipped with either of those engines, unless I would only keep the vehicle as long as it was under factory warranty.
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This has become a quite interesting discussion. The issue of engine oil viscosity and quality, combined with change intervals certainly is having an impact on engine and component life. @Rory428, add the issues you saw at Toyota to the clever, yet overly complex technologies that have been developed in an effort to comply with idealistically-inspired mandates, and these types of failures are inevitable. Many technologies are dependent on oil pressure/flow in order to actuate--variable valve timing is an excellent example. If you have an engine that relies on oil to operate it's clever tech, yet normally burns up to a quart of oil within 600 miles, you are going to see a lot of problems, all the moreso when so many people wait until a computer warning informs them there is a problem/low oil.
"...I don't know, it just made a funny quitting noise."
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we put 4K miles on the full synthetic too, lack of oil changes ruin engines
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As mentioned, variable valve timing often requires oil flow thru tiny, intricate passages, which can easily become plugged from sludge build up, and can be extremely difficult to clean out. A few other things with "modern" vehicles that concern me, are no engine dipsticks, so you can`t check the oil level or visual condition, but have to rely on either an "oil condition monitor " system, or an often confusing in dash computer procedure, rubber belt driven oil pumps, that live in oil (who thought THAT was a good idea?), that can cause early deterioration of the rubber, plus the material can cause rubber dust/debris to clog up the oil pickup screen. Also, now some engines don`t use a positively driven oil pump, but rather have a variable displacement oil pump, which reduces oil pressure , I imagine to reduce parasitic horsepower drain, which just seems like a bad idea to me. To me, it seems like many of these "innovations" , to free up any small amount of power, can come at a high cost. Things like "Start/Stop" engines, that turn off at a traffic light, cylinder deactivation, direct EFI, water thin oils with long drain intervals, VVT, etc, will in the long run, cost much more to maintain and repair than the amount of gasoline they will save. Same goes for diesel engines with all the emissions crap that has been added the past 10-15 years.
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This brings a question to my mind.
When buying a used modern car (2010 and newer) how can a person really tell what condition the engine/transmission is in?
Even the cheapest new engines are very good, and they will drive 60,000 miles without doing one iota of maintenance....which more and more seem to do.
This gets even more difficult to figure out when the new vehicle does not have ways to check the oil/trans fluid levels of the driveline parts.
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Had a car that wasn’t running right every once in a while throw PO 300 random cylinder misfire and just wasn’t idling smoothly and for this car it was out of the norm. Always did his maintenance. After a few hours of checking things out including the oil which was clean I called him to get more info. This problem started a few weeks before and I asked him if he’s getting gas somewhere else or anything that might help me then as we are talking he tells me that he changed his oil by himself 2 weeks ago and he used the same oil as his wife’s vehicle. I know his wife’s vehicle it takes 5/30 and his takes 0/20. I told him I was gonna try a few things I would call him later. I immediately had one of my guys change his oil and within a few minutes it was running perfect. VVT on some cars are much more sensitive.
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This problem of catastrophic rod bearing failure in the L87 is particularly interesting. There have been cases of it happening in engines with a few hundred miles on them. And not just a few claims. There is talk of a recall affecting over 800,000 vehicles as well as class actions being filed. GM has been disappointingly tight-lipped about it, although that's to be expected I guess.
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Not actualy related but.... conserning oil consumption. I fully rebuilt a 70s Mercedes Diesel
Including topdecking. linehoning.etc was running realy smooth and "strong" yeahh for 68 hp
but used some oil. The owner talked to an old Mercedes mecanic that said he had not seen
a Mercedes diesel run that good before. He told him when those
cars where new some used oil some did not. And they got a service message from Mercedes
to block of 1/3 or 1/2 the oil cooler,i dont remember on those that used oil. He did that and it solved the oil consumtion ???
I know in 73 or 74 they skipped the oil cooler entirely but that lead to bearing failures so next year
the oilcooler where back
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here you go.
https://bangshift.com/general-news/tech-stories/is-the-factory-wrong-about-which-oil-you-should-run-in-your-late-model-car-stop-following-oem-oil-advice-the-recent-gm-recall-proves-why/
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Rod bearing failures are always a treat to get to the bottom of because the failure mode is so rapid and destructive, rarely is there any good evidence left behind to help determine what the problem was or the root cause. Some of the failure modes that I have seen analyzing warranty engines at work are due to the following.
1. Contaminated / Dirty / Old / Overheated Oil. Oil with coolant, fuel, dirt, etc can take out rod bearings quite quickly. Navistar, Ford (6.OH-No!), and CAT engines from the 2000's and 20-teens that used EGR extensively to meet emissions are particularly prone to this. EGR cooler develops an internal coolant leak, and all the sudden your engine is trying to lubricate with the green stuff. I have also seen a bunch of rod bearing failures in air cooled engines due to oil overheating. When I was at a small engine manufacturer, the life span of the rod bearing was measured in minutes once the oil hit 350 deg. F.
2. Machining Quality. Everything from surface finish, journal roundness, corner radius all can affect the lifespan of the rod bearing, and it doesn't take much of a deviation or miss to shorten the life span from 100,000's of miles to 100's of miles.
3. Engine (casting) Contamination - See recent Toyota Tundra recall
4. Crankshaft design / flex. If the crank flexes more than intended or designed, bearing failure can result. Typically this is more of a main bearing related problem, but it can lead to rod bearing damage as well. PACCAR 13L engines are known to experience more crank flex than intended and this will lead to failed bearings.
5. Rod Bolt Quality. About 3 years ago, we started seeing a dramatic rise in rod bearing failures on Navistar I-Series reman engines. Turned out, the rod bolt manufacturer (Navistar chosen and vetted supplier) had changed their process and the bolts were softer and did not have the designed tensile strength. Bolts would stretch and lose clamp load on the cap, and the bearing would spin. We discovered the problem by doing an extensive statistical study on our DC tool data (torque and angle) from assembly. The failure rate was only 3 to 5% of engines, so it was difficult to catch, but there was a statistical change in the data. The bolts were close to being correct (a measured sample would often meet the engineering print and specs), and they would even torque, yield, and stretch properly during assembly, but would fail within 10,000 miles. We went down a number of rabbit holes before we figured out the root cause on this one. Navistar ended up recalling all the rod bolts at their dealers and assembly facilities.
6. Bearing Material or Quality. Doesn't take much of a change at the supplier to cause problems in the engine.
This would be a good "guess" - the bearing is the "victim" of something else in the system. Could be damn near anything. Given the level of electronic management in a new engine package, it could even be something in the software that controls timing and fuel. A bearing (or rod etc.) design that just meets or barely exceeds design needs won't have enough "headroom" to handle any unexpected loads.
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According to the Chev dealer local, the problem is crankshaft surface finish. I am surmising that going to a heavier oil, just delays the inevitable failure.
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This would be a good "guess" - the bearing is the "victim" of something else in the system. Could be damn near anything. Given the level of electronic management in a new engine package, it could even be something in the software that controls timing and fuel. A bearing (or rod etc.) design that just meets or barely exceeds design needs won't have enough "headroom" to handle any unexpected loads.
Your right, the bearing is normally the weak link that results in engine failure, rarely the actual problem or root cause. I have seen something similar on 3.9 Cummins 4BT Industrial motors. Ran fine and forever at the factory rated 85 Hp, but as soon as farmers started fiddling with the fuel pumps and attempting to squeeze a bit more power out of them, the rod bearings would quickly fail. Granted these were cheap aftermarket bearings, not Cummins OE, but the difference in lifespan between a stock 85 hp motor and one that had been turned up was startling.
According to the Chev dealer local, the problem is crankshaft surface finish. I am surmising that going to a heavier oil, just delays the inevitable failure.
If the root cause is incorrect surface finish, changing oil viscosity will do very little to help, and it might actually make it worse as the thicker oil just causes the Oil Pressure Relief Valve to open further and you see a larger pressure drop from one end of the crank to the other. In other words, the bearings furthest from the pump may be getting starved, especially at startup and low operating temps when the oil is at it's thickest.