I took my 30k mile 2016 Sierra 3500 to the dealer for an oil change and let them talk me into a fuel system cleaning over the weekend. They had an issue with it after the cleaning and didn't have a diesel mechanic on site who could look at until Monday. Ended up having compression issues with several bent push rods. Any thoughts on how badly they could have damaged the engine or what they could have done to cause this? They said the valves and springs are fine.
txn
How did they determine there is no valve damage?
Because if the push tubes are bent, that generally doesn't happen unless the valves hit the piston.
How many are bent? And did they say what happened before that? Did they spray anything in the motor and cause and overspeed?
Because if the push tubes are bent, that generally doesn't happen unless the valves hit the piston.
How many are bent? And did they say what happened before that? Did they spray anything in the motor and cause and overspeed?
They took the valve covers off and visually inspected them.
They haven't given me any details on what happened except for the turbo "popped" when it spun up after the cleaning. Enough were bent that they are replacing all 16. Haven't gotten ahold of the service manager to get details on what exactly they did with the cleaning or how many were bent. The fact no one on site was qualified to troubleshoot the issue after they serviced the truck is concerning. I'm worried other components could be stressed from whatever happened and could fail down the road from this.
They haven't given me any details on what happened except for the turbo "popped" when it spun up after the cleaning. Enough were bent that they are replacing all 16. Haven't gotten ahold of the service manager to get details on what exactly they did with the cleaning or how many were bent. The fact no one on site was qualified to troubleshoot the issue after they serviced the truck is concerning. I'm worried other components could be stressed from whatever happened and could fail down the road from this.
Well you can't see the valves from under the valve covers so I'm not sure how they inspected them. All you can see is the very top of the valve stem, and the springs. They could have bent stems and you may not be able to see that from just taking the valve cover off.
The pistons could also have damage to them if they did indeed strike the top of them. And if the valves are bent, I have seen them gouge the head, and being an aluminum head, it isn't that hard to do.
I'd also definitely be concerned about the events leading upto the bending of the push tubes. In fact, I'd be more concerned about that knowing they managed to bend the push tubes.
The pistons could also have damage to them if they did indeed strike the top of them. And if the valves are bent, I have seen them gouge the head, and being an aluminum head, it isn't that hard to do.
I'd also definitely be concerned about the events leading upto the bending of the push tubes. In fact, I'd be more concerned about that knowing they managed to bend the push tubes.
This is a common thing as someone takes there truck into the dealer for a simple oil change an something else seems to happen why the trucks in there, your best bet is to look around in your area for a legit diesel shop an have them look at it. Not saying all dealers rip you off but 95% do cause like you said no one qualified to work on a diesel told you something was wrong, spend the extra money an take it to a reliable shop the first time, cause by now you pull it out of there pay them an pay a legitimate shop your into a lot of money
Thanks for the replies.
I've got a call lined up with them tomorrow and am hoping to get exact details of what they did ahead of this. How many cylinders failed the compression test afterwards, and how many rods bent.
Going to another mechanic is my backup plan and for future work. For now they are covering the costs, but I'm thinking they should be replacing more than just the rods to make sure I don't have other parts break. The warranty expired about a week before this so giving them a chance to make this right. My thoughts are it was a practically new engine when I dropped it off and now a fair amount of it could be stressed.
I've got a call lined up with them tomorrow and am hoping to get exact details of what they did ahead of this. How many cylinders failed the compression test afterwards, and how many rods bent.
Going to another mechanic is my backup plan and for future work. For now they are covering the costs, but I'm thinking they should be replacing more than just the rods to make sure I don't have other parts break. The warranty expired about a week before this so giving them a chance to make this right. My thoughts are it was a practically new engine when I dropped it off and now a fair amount of it could be stressed.
I predict whatever they were using to clean the fuel system got into the engine and my guess is that the substance was very flammable compared to diesel. So, easy to see an engine overrun as some dope does not know diesel. That's my .02.
From talking to a couple guys at work who have owned diesels for years they were thinking either 1) like you said, they got something highly flammable in the engine and caused a severe detonation or 2) they flushed it with something, didn't drain it, and hydro locked the engine. One of them said I should be demanding a new engine if they hydro locked it (I realize this is probably a pipe dream).
If they admit that it was something from the cleaning got into the engine and caused an overrun do you think having them just cover the rods is sufficient or I should be going after them for more?
From what y'all have said, I'm thinking the next step if the only thing they are willing to do is replace the rods is have it towed to a diesel shop and have them inspect the valves and pistons for damage.
First diesel I've owned and by no means an engine expert so any advice is appreciated.
If they admit that it was something from the cleaning got into the engine and caused an overrun do you think having them just cover the rods is sufficient or I should be going after them for more?
From what y'all have said, I'm thinking the next step if the only thing they are willing to do is replace the rods is have it towed to a diesel shop and have them inspect the valves and pistons for damage.
First diesel I've owned and by no means an engine expert so any advice is appreciated.
So you took your perfectly-running truck in for an oil change, and they get you to do the 'fuel system cleaning' and now, your truck has popped turbos and bent valves. They trashed your truck my friend.
Pushrods bend when valves hit pistons. That's it. I doubt highly that any sort of detonation event could've caused this - diesels run off 'detonation events' more or less... Although, as was said, if they tried to run some sort of gasser injector cleaner through the engine, it could've oversped the engine. Hearing that 'turbo popped' also sounds like it would support this theory. Bent pushrods also should not cause low compression - a bent rod becomes 'shorter' and cannot adequately travel to open a valve any longer. Low compression means bent valves, bent connecting rods, cracked pistons.
I feel they probably hydrolocked your engine. That will mean more than bent pushrods. Connecting rods, pistons, valves. Lots of stuff bends and breaks when non-compressible fluids get trapped between the piston and the head.
Two things to keep in mind here. You took a healthy, running truck in to a dealer for service. You now have a dead truck after their service.
I would not be having any conversation with anyone that involves taking the truck to another shop for repairs or paying for any repairs out of pocket. Your 30k mile, 5 year old truck should have power train warranty regardless. Pushrods and pistons are power train. You need to demand the dealer tear the engine down. You need to get GM involved asap. If the dealer or GM does not want to play, file a claim on the dealer with the BBB in your state. Do not accept any dealer B.S. that the engine was hurt/damaged before you bring the truck in. This is them trying to screw you. Most states also have a Bureau of Automotive Repair (or equivalent) that regulates dealers trying to do shady stuff. Reach out to them.
Best of luck, we're here to help.
Pushrods bend when valves hit pistons. That's it. I doubt highly that any sort of detonation event could've caused this - diesels run off 'detonation events' more or less... Although, as was said, if they tried to run some sort of gasser injector cleaner through the engine, it could've oversped the engine. Hearing that 'turbo popped' also sounds like it would support this theory. Bent pushrods also should not cause low compression - a bent rod becomes 'shorter' and cannot adequately travel to open a valve any longer. Low compression means bent valves, bent connecting rods, cracked pistons.
I feel they probably hydrolocked your engine. That will mean more than bent pushrods. Connecting rods, pistons, valves. Lots of stuff bends and breaks when non-compressible fluids get trapped between the piston and the head.
Two things to keep in mind here. You took a healthy, running truck in to a dealer for service. You now have a dead truck after their service.
I would not be having any conversation with anyone that involves taking the truck to another shop for repairs or paying for any repairs out of pocket. Your 30k mile, 5 year old truck should have power train warranty regardless. Pushrods and pistons are power train. You need to demand the dealer tear the engine down. You need to get GM involved asap. If the dealer or GM does not want to play, file a claim on the dealer with the BBB in your state. Do not accept any dealer B.S. that the engine was hurt/damaged before you bring the truck in. This is them trying to screw you. Most states also have a Bureau of Automotive Repair (or equivalent) that regulates dealers trying to do shady stuff. Reach out to them.
Best of luck, we're here to help.
Not sure if this is related, but it might be worthwhile to checkout. At 5000 miles my 17 Duramax puked while towing my toyhauler, had to have it towed to the dealer and they found out the pushrods were bent. They replaced them all and told me that this was a known issue where GM got a bad lot of pushrods. With yours being a 16 and mine a 17 there is probably a slim chance they are the same, but stranger things have happened.
Don't get me wrong. I'm pissed, but trying to stay calm until I at least have something in writing from exactly what happened. Finally got some answers from them which are pretty much what jharp expected.
- overboost from flare up during the fuel cleaning.
- A bent pushrod caused the compression issues and the valves are fine. (pretty sure this isn't right)
- just received this from them "performed compression test found good compression 375 -400 lbs. in all cly. reinstalled glow plug have no start with popping from throttlebody". So there is a chance someone misspoke earlier in the week. Trying to get a copy of the test results with date/time.
- only the push rods would have been damaged. Nothing else could have been harmed or stressed from this and they are designed to give so nothing else is damaged. (I am not buying the nothing else would be stressed)
- The engine was not trashed and will be good as when I brought it in after the rods are replaced.
- they are sending me all of the test results and back and forth with GM that they have been having this week.
The push tubes will likely bend before the valves bend, they are softer so that should be the 'crush' point. Sounds like they don't know what they are doing on a diesel for a fuel system cleaning though- if they put it in the intake tract like happens with a fuel system clean (which includes the intake cleaning) on a gas vehicle, it gives it an unmetered fuel source to run off of- basically causes a runaway. I would be very cautious of them and their repair in this situation, as well as moving forward
They were honest from the start that the diesel mechanic wasn’t on site the day of the issues and he has been the one working on it after that. So I’m thinking if it really only is the pushrods I’d trust his work replacing them (assuming someone convinced me there aren’t other issues). Lesson learned to take it to a diesel shop in the future. The real question now is what else could have been damaged and if it didn’t actually fail the compression test does that change things.
The forces required to bend the pushrods puts HUGE loads on the lifters and camshaft. You need a written, lifetime, guarantee on your trucks engine, or they should give you well beyond trade in value on a 2021.
Sure, it will run for awhile with new pushrods....
But when this thing goes "POP", its going to be on your dime.....
![1084854]( "1084854")
Sure, it will run for awhile with new pushrods....
But when this thing goes "POP", its going to be on your dime.....
The more I think about this, the more I realize you've been really screwed..
Search "LML CP4 failure" on this board. You're head will start spinning.
It's a known issue on the LML's under the best of circumstances.
Overspeeding the crap out of it, didn't do it any favor's.
If the dealer wont give you a written, iron clad, lifetime engine warranty that cover's the fuel system too..... it's time for you to Lawyer up....
Search "LML CP4 failure" on this board. You're head will start spinning.
It's a known issue on the LML's under the best of circumstances.
Overspeeding the crap out of it, didn't do it any favor's.
If the dealer wont give you a written, iron clad, lifetime engine warranty that cover's the fuel system too..... it's time for you to Lawyer up....
I agree with the rest of these guys, be prepared to make them cater to you, and make you feel comfortable driving the truck again.
But at the same time, what they did is not okay. These are certified techs, not average grease monkeys. Honestly, I dont even know what a "fuel system cleaning" consists of, never heard of doing it to my lml... but they surely used something in your engine that shouldnt have been in there. And that is concerning.
Personally I'd be leaning toward telling them to buy the truck back, or get yourself a comparable payment on a newer model without cp4. With 30k on the truck... that must have had a steep price tag even being 5 years old.
Who knows where you'll be, or when that engine could fail now. Like you said 'trust' that's a big thing with your vehicle.
But at the same time, what they did is not okay. These are certified techs, not average grease monkeys. Honestly, I dont even know what a "fuel system cleaning" consists of, never heard of doing it to my lml... but they surely used something in your engine that shouldnt have been in there. And that is concerning.
Personally I'd be leaning toward telling them to buy the truck back, or get yourself a comparable payment on a newer model without cp4. With 30k on the truck... that must have had a steep price tag even being 5 years old.
Who knows where you'll be, or when that engine could fail now. Like you said 'trust' that's a big thing with your vehicle.
So they sent me passing results from a compression test (just the summary that all were between 375-400) so it looks like it was a miscommunication that it had failed one. Probably should have talked to the tech working on my truck days ago instead of the server coordinator to clear that up. From going back over voice-mail it looks like they were concerned about compression issues and then either I missed it or they didnt mention they tested it and it passed. So they still screwed it up, but hopefully this means I won't have any valve or piston head damage they didnt find.
They admitted it was overrun from a flare-up after the cleaning so unless I am missing something I can see how that could result in 4 bent rods without valve damage. Probably stressed the lifters and having something in the fuel system that shouldn't have been there and was probably more flammable than diesel I'm assuming the fuel system could have been harmed.
Warranty hit the 5 year mark about a week before taking it in.
From other things in the past I've already had to replace wiper fluid pumps and sensors, DEF injectors and pumps, and the ECM from what I think was one electrical issue, part of the dash was warped when I went to pick it up which that dealer replaced. Horn assembly. Those were all warranty at least. Different shop for those. Makes me consider the new truck option though considering all the issues within 30k miles and now I'd be worrying about mechanical issues on top of all of that.
Sounds like realistically my options are
1) lawyer which I imagine is going to turn into a pain and not be a quick process, have an upfront cost I may not get back, and could result in not having a truck for a while.
2) They replace the rods (they did order a replacement set of 16 that they are covering. Not saying that is enough, but at least they admit their work was the reason they need replaced and they did it without me having to ask) give me detailed compression test results with readings per cylinder to confirm that it wasn't an issue and extend the warranty by a couple years. I would still need to get them to agree to the warranty. Kinda feel like this is only better in the short term and still could bite me down the road. Also still run the risk of breaking anytime and anywhere even if the costs would be covered.
3) Get them to buy it back and get another truck. I've only got two payments left on this one so not loving the idea of starting that again. I've done a bumper swap, added steps, and a headache rack to the current truck which I'd need to repurchase for a new truck. Probably the most expensive short term for me and let's them off easy, but sounds like the easiest and quickest way to be driving a reliable truck again. This is the first vehicle I've bought new and first diesel so I'd like to keep it, but thats probably more sentimental reasons than a good idea.
They admitted it was overrun from a flare-up after the cleaning so unless I am missing something I can see how that could result in 4 bent rods without valve damage. Probably stressed the lifters and having something in the fuel system that shouldn't have been there and was probably more flammable than diesel I'm assuming the fuel system could have been harmed.
Warranty hit the 5 year mark about a week before taking it in.
From other things in the past I've already had to replace wiper fluid pumps and sensors, DEF injectors and pumps, and the ECM from what I think was one electrical issue, part of the dash was warped when I went to pick it up which that dealer replaced. Horn assembly. Those were all warranty at least. Different shop for those. Makes me consider the new truck option though considering all the issues within 30k miles and now I'd be worrying about mechanical issues on top of all of that.
Sounds like realistically my options are
1) lawyer which I imagine is going to turn into a pain and not be a quick process, have an upfront cost I may not get back, and could result in not having a truck for a while.
2) They replace the rods (they did order a replacement set of 16 that they are covering. Not saying that is enough, but at least they admit their work was the reason they need replaced and they did it without me having to ask) give me detailed compression test results with readings per cylinder to confirm that it wasn't an issue and extend the warranty by a couple years. I would still need to get them to agree to the warranty. Kinda feel like this is only better in the short term and still could bite me down the road. Also still run the risk of breaking anytime and anywhere even if the costs would be covered.
3) Get them to buy it back and get another truck. I've only got two payments left on this one so not loving the idea of starting that again. I've done a bumper swap, added steps, and a headache rack to the current truck which I'd need to repurchase for a new truck. Probably the most expensive short term for me and let's them off easy, but sounds like the easiest and quickest way to be driving a reliable truck again. This is the first vehicle I've bought new and first diesel so I'd like to keep it, but thats probably more sentimental reasons than a good idea.
Man this whole situation really sucks. I really don’t know what I would do if I was in your place. Just throwing out an idea here: maybe talk to a certified diesel tech from another shop. If their opinion is that a complete tear down should be done, have them put it in writing and their name beside it and take it to the dealer. Also, if you go the trade in route, I wouldn’t settle for less than retail value not trade in. I think your owed at least that and probably more. Anyway, no matter what you do, I feel for you.
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Some of these dealers have real idiots working who joy ride your nice cold vehicle and you have no recourse...
Basically what has happened is what you see alot on here with ether/starting fluid talk. They say to never run it or it causes issues with predetonation, dry cylinder firing, and uncontrollable revolutions. Idk how many times I've seen on dmax forum especially to never use starting fluid or anything in these intakes.
In order to bend pushrods, they had something in your system that everyone one here preaches to avoid. Except me, lol. But I'm not an idiot w it n have no intake heater. Either way, improper practice by uncertified techs resulted in your engine failure. Thats a serious issue whether they "fix" it now or not. No telling what kind of stress bottom end saw, valve adjuster screws saw, lifter/lobe, the list goes on. And the techs know that, but their boss won't admit to it.
In order to bend pushrods, they had something in your system that everyone one here preaches to avoid. Except me, lol. But I'm not an idiot w it n have no intake heater. Either way, improper practice by uncertified techs resulted in your engine failure. Thats a serious issue whether they "fix" it now or not. No telling what kind of stress bottom end saw, valve adjuster screws saw, lifter/lobe, the list goes on. And the techs know that, but their boss won't admit to it.
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