MrLeadFoot

You are bringing up something I've been wondering about ever since this "test" came out. I can't help but wonder if this recall "resolution" is smoke and mirrors to placate the NHTSA, and that the picoscope really can't tell them anything until something has already gone wrong. I would think that there are variations in every motor, which would create quite a wide range from which to try and detect something "abnormal", and by the time something abnormal was detected, it would already have developed other symptoms, or soon would, anyway. But, this way, GM can at least they can show they made an "honest" attempt to help detect and pre-empt failures.

Yes, that would be good news, but @newdude doesn't know for sure, yet. Let's hope he finds out for sure that it went down like he suspects it did.

Do you happen to know if the failure was based purely on the pico test only, or if it had already shown symptoms and/or thrown a code?

I should add mine, too. Yesterday. 22 Sierra, 30,500 miles.

Understandable why you posted your initial question on this thread. That said, maybe you should start a new thread. That way your issue doesn't get lost like it might on this recall thread. A new thread might also attract the attention of someone who had a similar situation as you and has a sound resolution. In the meantime, @Black02Silverado has a good suggestion about checking grounds, as that would indeed cause the same symptoms. He's also correct about today's starters, espcially those designed with auto-stop functionality in mind. Those are specifically designed for super-long duty cycles, with auto-stop frequency factored in. But, starters don't like heat. I remember long ago, an exhaust manifold pipe on one of my cars got so hot I would get the same symptom you're getting. A thermal wrap solved it. I doubt that's your problem, just offering a point of reference. I've also had vehicles where the nut on the power post on the starter was not as snug as it should be, and the weak power connection got the same symptom. Kind of like when your battery terminal isn't completely snug, and it causes the starter to struggle on its initial turn. Finally, I've also has starters do what you describe, but they were all super old, and eventually locked up after some time. Since yours is so new, I would check ground and other electrical connections before going after the sarter. It's always a party when you find something as simple as a loose nut.

Wow, you don't even drive that thing! I wouldn't think a starter is already worn out to the point it's binding up, but then again, stranger things have happened. But, sure sounds like battery or starter, to me. I would first double check that that new battery is indeed the right amperage and that it is not old, or something. At least you'll know if it's recall related once you get inspected. I would think they would detect somethimg with the pico test with your symptoms, if it is recall-related. FWIW, I just got my notice to get inspected, so maybe yours will come soon.

That is odd. Sounds like something is getting too hot. A mechanical engineer I know said the reason they are switching to thicker oil is because they are afraid of heat. Not trying to scare anyone, but the failures haven't been sudden. They take time to develop. That's why many have had thousands of miles on them before giving up the ghost. Good news, in your case, is that it seems to run fine once started. If it were bearings starting to seize, it would continue to "drag", to say the least, once it's running. If it hasn't seized and it the bearings have spun, you would certainly know it. Maybe the starter is getting too hot and binding? How many miles on your truck?

Damn, I hope that ever happens to me while towing!

Thanks, Newdude, for setting me straight. I don't know how I missed that part about the grade percentage. That must be it. I remember using HDC on long boat ramps last year when the lakes were low, and it was nice, and it always worked, but I bet boat ramps are steeper than 10%. This year I've been frequenting a lake that has some pretty steep grades going around its dam to the launch ramps. Instead of pumping the brakes, I remembered I have HDC, and when I tried it on the last 2 trips it only worked sometimes on the same grade. I bet it's because that grade is just about 10%. I have HUD so I will set it to the appropriate display to monitor the grade. Again, thank you so much for pointing this out.

Like the title says, it seems to not engage all the time, although the indicator indeed illuminates on the dash. I've tried while going downhill with and without my boat in tow, on flat roads, and while going anywhere from 5- 25 mph. Tried pressing the button to turn it on while moving and from a stop. Sometimes engages, sometimes doesn't. Tried while rolling downhill without foot on the brake, and then again while braking. Same thing. Then, on Wednesday, while towing my boat it suddenly engaged when I was showing a passenger how it doesn't work, then later on the same drive it didn't engage again. Tried it in Normal mode and in Tow mode, in D and L transmission modes. User manual doesn't really say anything about any special conditions that need to be met to have the function engage. Is there a secret to this, or is mine malfunctioning? If it is malfunctioning, would this throw a code that a standard, non-Tech II OBDC reader would pick up? Thanks in advance.

Thanks for the explanation. I learn something new every day.

See what I mean? OK, big man, you got the last word. I've got no more words for you. Now, can we get gone, like your handle says, and move on? Sheesh.

Just curious, is it standard practice for them to try to turn it over by hand in a case like this, or were they just simply trying to do it for grins given the nature of this recall?

I had a 69 El Camino with no power steering and no power drum brakes, so that's not the issue. The issue is when you are in a downhill turn and the wheel is turning easily, and the brake pedal is an easy push, and as you continue turning everything suddenly stops "assisting", the vehicle continues moving faster, and the steering feels like it's pulling you in the opposite direction. Sure, you can muscle it, IF YOU HAVE TIME to react. And, if it's raining, and you yank that wheel to overcorrect, you can break traction. The stock Alenzas on 22s are way better in the rain than the stock Duehlers on the 20s, and at the time I had the stock 22s on the vehicle which turned out to be a blessing. Turning in an intersection at a low speed is a much different animal, in terms of having time to react, compared to an egine suddenly seizing at highway speeds. That's all I'm saying. Can we get back to our regluarly scheduled programming now?

So, we are flexing our manhood now, are we? Oh wait, you can't, you're 51. How about I brag all day long about what a great driver I am, having raced cars, having lived in NY, driving in blizzards in my manual transmission 68 Camaro SS, and flying down the highway in my 78 Trans Am 455 with tornadoes around me in Nebraska, but who gives a rat's a$$? Would any of that contribute to this thread? No, so stop being so immature, and let's get back to the subject of this thread, shall we? You always seem to be so combative in your posts. Whatever you must be going through, I sincerely hope things work out for you.

Until you've been in such a situation like that, you have no idea what the experience is like. It's also easy to sit and analyze something after the fact, but when you are in the middle of a downhill turn in the dark in a storm, and everything up until that point was working fine (the engine, brakes and steering reacting to the lightest touch), and then suddenly everything loses all responsiveness, you simply don't have enough time to react. I can tell you that at that moment, navigating a 90 degree downhill turn in a storm at night becomes a critical manuever when you have no engine power and no electrical power to your steering or brakes. I'm just lucky everyone else on the road saw that I was suddenly going too wide, and too fast into that turn, and all stopped. Ironically, it was at that moment I realized just how good those Bridgestone Alenzas are in the rain, because I seriously thought I was going off the road, and down the mountainside. I can only imagine what might happen if an engine completely seized or self-destructed on a highway turn at night in the rain. I will give GM kudos in this case, as they immediately initiated a "safety buyback" conversation with me. And, I did not start that dialog with them, they started it with me. But, that matter is beyond the context of this thread. If you hear a rod knock or feel the engine hesitating, etc. you have fair warning and ample time to coast to the side of the road. But, if you THINK you know what's going to happen if your engine suddenly seizes, actually throws a rod through the case, or otherwise suddenly self-destructs, and you THINK you know what you would do in that situation, NO YOU DON'T! Because it will be so sudden you won't have time to react. Sure, this can happen with any engine in any vehicle, but in the case of this recall there were thousands of reported and verified issues before this recall became official. And, there are more and more engines breaking down, as you have seen yourself. This means there is a real problem. I'm just not so sure GM is really doing what they need to do. I'm not sure myself what they should be doing, but it sure feels like they're playing a numbers game and trying to placate folks (NHTSA and customers) with this Pico test. That's why I've been trying to find one, single instance of a motor being repaired/replaced as the result of a Pico test, and I cannot find one such case anywhere. That, right there, is quite odd to me. Changing to 40w oil is indicative that there is worry about heat in the crankcase. What is causing this heat that is beyond far beyond what they expected in this engine? Friction, that's what. And, your pics only add confirmation to all the other findings already made public about where that friction is coming from. Why is it, then, that not one engine has been replaced due to Pico findings? Either the pico test doesn't work (which I doubt), or GM is trying its best NOT to replace compromised engines, and instead are trying to use 40w oil to eke out 150k miles out of engines that should SAFELY go 300k miles.

When an engine blows many incidental things can happen including electrical interruption. I share the following with you that might help open up your thinking. The first week I had my truck, I was sitting in the left turn lane at an intersection on a rainy night. The truck auto-stopped. The left turn arrow turned green, I took my foot off the brake, and the truck started. I stepped lightly on the accelerator so as not to lose traction on the wet road and began my turn. Halfway through the intersection, I suddenly had no engine power. I didn't know what was happening and saw a message on the dash saying something about putting my foot on the brake to start the car. I put my foot on the brake and nothing happened, no brakes, nada! I tried turning the wheel and the car would not turn. Fortunately, the wheel was already turned and I made it through the intersection, and the road I was turning onto was uphill. The incline was steep enough to stop me before the truck oversteered into oncoming traffic, although I was then stopped ******-eyed in the middle of my lane. I shut the truck off and restarted it. The next day I took it into a dealership. They said they tested everything and nothing seemed amiss. They also said with all that had happened, there SHOULD have been some kind of code thrown or stored. Well, guess what? No codes. So, believe me when I tell you, that sh|t happens, whether it's supposed to or not. I lost steering and brakes and my engine hadn't seized and all power was still on. You go ahead and believe you might not have a disaster when your motor siezes at night in the rain going around a corner on a remote highway somewhere, and I will hold onto my shares in the tinfoil hat company. Sheesh!

The pico test is supposedly in place to detect problems before an engine failure so they can replace said engine before it breaks down, but I have not heard of one instance anywhere (not just here) where an engine that had not already developed a serious issue failed the pico test and was replaced due to the results of that pico test, have you? Regarding old guys using stethoscopes: I don't need a stethoscope. I've used aluminum tubes, long socket extensions and more to listen for things like valves that need adjustment, bearings that are going, which pulley needs replacing, etc., so I know that a pico scope can detect oscillation and it should theoretically work. But whether or not it works is not the issue. It's a matter of whether or not GM will actually replace an engine due to pico scope findings. With all the tests done so far I haven't heard of one. And, while @newdude has been so kind as to keep us informed of engines are breaking down, broken engines appear to be the ONLY ones that are being replaced.

Exactly! They would have to crash, possibly into into someone else, because of a lockup that causes them to lose control. Maybe the engine dies going downhill around a corner, compromising the power brakes or power steering. Or, your truck locks up and you get plowed into by a big rig on said downhill turn. The scenario possibilities are endless, but the likelihood is small. It's all a numbers game. That's how recalls, and liability, works. That's why actuaries have jobs. And, that's why they are likely doing these pico tests. They will have record of at least doing something to mitigate liability. As was said, above, they're not going to replace a running engine. However, if someone dies, they just might start doing something proactive to preempt any future morbid events. It's not unlike when they finally add traffic lights at some intersections or guardrails on highway turns. Even when those intersections and turns already seem dangerous. It's not until a disaster happens that they spend the money. Happens all the time.

Yeah, I'm kind of suspecting that the test might very well be just their way of placating the NHTSA. I hate to be morbid, but it's possible that someone will have to die from this problem before they get serious.

Thanks for updating us. Have you heard of ANY engine replacements at ANY dealership based on a failed test, that was not an engine that had already broken down or developed obvious problems?

I'd like to know if a motor, that the owner hasn't experienced an issue with, ever gets replaced based on the results of the test, you know what I mean? In fact, I haven't heard of any that have been, not even in the media.

So, in reality, this had nothing to do with the recall inspection itself, so we still don't know if the inspection really works to detect a problematic engine BEFORE it goes kaput, right?

So sorry to hear this, but it figures. It's so disappointing what's happened to GM. They're just lousy at making these trucks comfortable to drive. It almost seems like they think gadgets and amenities make up for lack of ergonomics, comfort and noise. I know it's a different chassis, but my 2000 Suburban was SO much more comfortable than my 22 Sierra Denali. And, that Suburban gave me no major problems, although it did drink oil. But, even so, I sold it with 235k miles on it, and the buyer was thrilled at the condition of it. All my friends had older trucks that, even though they weren't as luxurious as the new ones we all have now, felt more robust or something. I can't put a finger on it, but I find myself worrying more about something going wrong with my Sierra more than I ever did with my Suburban, my 93 Vette, and the 2001 vette i still have. I seriously wonder if Mary Barra changed the culture to one that thinks more bells and whistles means more comfort, when in reality wind noise, vibrations, and seemingly little things like visibility (aka blind spots); omission of windshield eyebrow tint (resulting in way more heat in the cabin on hot days even with the a/c on full blast); omission of rear door handle unlock buttons; cheap, noisy, pop-up fabric sunroof wind deflectors, and the like all detract from what once was the best in the business. Spending a little more time on ensuring wind noise is suppressed and addressing the vibrations alone would make for a much more comfortable ride and attract more of the luxury buyers, since these trucks are already in the luxury price range, but are nowhere near as comfortable as true luxury. Ironically, my truck has been serviced at multiple dealerships, and when I voiced concern about something that isn't quite the way it's supposed to be, more than once the response has been "... it's not a Lexus." Makes me wonder if that's what they are taught to say! Darned right it's not a Lexus, because if it was, it would have been cheaper, price-wise, and designed and assembled with better attention to detail. We always boast about how things made in America are of better quality, yet you just bought a new 2025 truck from the company whose CEO said just the other day in an interview that these trucks are their strongest earners, but you have excessive wind noise? Unbelievable! (Getting off my soap box now)

Oops, my bad. In my haste, I didn't word things quite correctly. That'll teach me not to rush. Mine is the type that has a slotted bracket attached to the interior panel of the cover. A short carriage bolt slides into the slot and a notched piece goes over the bolt. And, as you described, the notch nestles right onto the track. A star knob acts as a nut on the bolt, and cinches everything down, which in turn pulls the top down onto the rubber on top of the rails. But, that rubber is firm and slippery. I don't see how anybody's top would not shift forward because there is nothing in front to stop the cover from sliding or vibrating forward over time. If I grab my cover from the back and pull, or push, it moves. But, now that I put the stock rail clamps behind, and butted up to, the notched pieces, and those two little Chinese clamps in front of the hold-down clamps, the cover simply can't move. Still can't belive mine is the only ones that moves.