Chevy and GMC Duramax Diesel Forum banner

"OFFICIAL" LML Blown Engine Thread...

134K views 225 replies 93 participants last post by  dustanperras 
#1 · (Edited)
"OFFICIAL" LML Blown Engine Thread...

Ok, fellas... I'm on a hunt to see how many people have been having engine issues with their LML, specifically piston failure... I've quit counting how many haulers in my area here have '15s that have had pistons grow holes... I'd like to figure out if there is a problem with the pistons, or if these issues are specific to deleted trucks, or specific to certain tuners, etc... I do know that the pistons have been getting less and less material with each passing generation of engine. I wonder if they just got a bit to thin in the later LML's, or what's happening... I'm also very interested in how the L5P pistons will hold up to heavy hauling in the long run...

This is what I'm looking for...
1. What year is your LML?
2. Stock or deleted?
3. If deleted, how many miles stock, and how many miles deleted?
4. If deleted, what tuner?
5. What other mods if deleted?
6. Under what circumstances did your pistons fail? Normal driving, racing, towing, etc...
7. In what cylinder did the piston fail?

Any pictures of carnage would be great!! >:)

My experience:

I haul heavy, grossing 20-26k daily, and have been from the 1st day I got the truck. The truck was deleted around 120k, I had no issues whatsoever with the truck up until this mileage, one day it gave me reduced engine power. I turned it off, back on, and got home, but immediately deleted. At 170k I was loaded around 28k one day, pulled hard all day in the WV hills, notice very slight blue smoke out of the tail pipe all day, and that evening on the way home, empty, up a slight grade on the interstate, the truck started shaking and belching blue smoke. I immediately knew what had happened, so I got another truck to pick me up and hauled me home. And the rebuild started...

2015 GMC SRW 3500...
Stock for 120k, deleted ever since 120k, blew motor at 170k...
Kory Willis (PPEI) heavy tow tune
Stock downpipe, 5" straght FloPro
Failed while empty after a day of pushing it fully loaded...
Piston #7 failed for me...



Looking forward to seeing what all has happened out there already...



 
See less See more
2
#5 ·
I've read of plenty incidents on the different DMax forums, hoping everybody chimes in... If you know of somebody somewhere, link them to this thread, or post for them if they're not on the forum...
 
#14 ·
All my injectors tested good, I'm still running them now... I'm thinking it was a combination of my oil getting to hot, and to high EGTs... My coolant was higher that day than it ever was, which was a sign to me that the oil was plenty hot. I didn't have an EGT probe in then yet, so I don't know what they actually were...

I'm very interested in this. I've only had mine since June 2016 and haven't been able to wear the "new" off yet but I do have plans for it down the road. Definitely would like to know if there is a particular cause before I start dumping money into it. If you care to share at this point, do you personally think it's more strictly piston construction or it was another failure, modification or type of use that exposed the lighter piston?
I have a piston out of my '11 dually, a piston that came out of a set of bank-specific pistons, and also have the one that went bad out of my '15. I'm gonna cut both of them down the middle, and see if there's any difference in them. I was told numerous times that piston production was moved overseas around 2013. Did anybody else hear anything of the sort? That would make me wonder a bit if they were...

15.5 lml Denali dually
29k miles
#7 cylinder cracked
PPEI tuning

WOW! That thing got a working over!! Wonder what made it split rather than get a hole inside the bowl? Do you know if that truck was used for towing, or just a DD?

Was everyone towing when there shit went? or lifted? or a combo of both? Also in everyone that I have seen with a blown motor that is tuned is using ppei.. Not bashing just stating what I have seen.. Trying to put pieces together
Exactly what I'm trying to figure out, if there is a certain factor tying all the different incidents together...
 
#8 ·
I'm very interested in this. I've only had mine since June 2016 and haven't been able to wear the "new" off yet but I do have plans for it down the road. Definitely would like to know if there is a particular cause before I start dumping money into it. If you care to share at this point, do you personally think it's more strictly piston construction or it was another failure, modification or type of use that exposed the lighter piston?
 
#10 ·
Was everyone towing when there shit went? or lifted? or a combo of both? Also in everyone that I have seen with a blown motor that is tuned is using ppei.. Not bashing just stating what I have seen.. Trying to put pieces together
 
#22 · (Edited)
Man I would be willing to say we tune 25-50% of all tuned LMLs... So the chances would be higher.

FWIW - I tow at 600rwhp@1250-1400* egts. Engine temp gets to around 215 on sustained 45+psi of boost on inclines. I have blown intercooler, but thats about it. EOT was getting very warm from the compounds, so i switched to synthetic oil and the issue has been very low now.

For me to hit 600rwhp, it takes a opening time of around 1900uS duration on the injectors. You guys at 500 and sub 500hp will be around the 1500uS mark. The main thing to monitor is EGTS... keep egts down below sustained 1350 range and you should be fine. Just note: GM makes replacement pistons not because only around 2% of the Duramaxes on the market that are tuned - but rather than parts just fail over time... and sometimes - soon than others.
 
#17 ·
Subd................

And now im super Fing nervous
 
#25 ·
How about a " seasoning" factor? When you get a new motor, aluminum steel alloys, heat soak plays a big factor when when running in a new motor. I know there's talk that guys buy these trucks with 0 on the clock and put it right to the floor and run it hard and have no issues.
I ran conservatively for 1000 then got harder and harder on it and now at 49k and still running strong.

Just a thought ?????


Sent from my iPhone using Tapatalk
 
#26 ·
@FC5452 what do you use your truck for? Do you DD it empty, or pull a trailer? I'd like to hear more input from others on what you shared, "seasoning", or break-in... I've always pulled from day 1 with mine, and never had issues before... Not beat on it, mind you, but worked it good... My brother-in-law has always done the same thing with his new DMaxes that he hauls with since he started on 2006, and has never had issues with any of his...


Sent from my iPad using Tapatalk
 
#27 ·
I have always "broke in" a new engine by driving it for about the first 1000 miles with varying rpm and some heavy acceleration mixed in with normal driving. After that, I change the oil to get the initial shavings and casting impurities out and use her for what she was meant to do. My current pickup I changed oil at 800 miles then hooked a 11000lb load behind it and set the cruise at 75 down the interstate. That trip I burned a little over a quarter of oil (obviously rings weren't seated), but now at oil changes I can barely tell any change in oil level after 5000 miles. The truck is mainly used to pull camper, haul stuff for the farm when needed and haul snowmobiles to the mountians. Not saying what I do is right either but I have never had any issues with this process.
 
#28 ·
M.A.M this is semi-related to this thread, but What tune were you running if any?
 
  • Like
Reactions: Heeb3
#32 ·
Does your brother-in-law tune his trucks,and if he does what tuner and tune is he running?

BTW when you started your motor build thread
I dropped my tune to optimized stock from tow tune.Your blown motor scared me LOL.
 
#33 ·
2015.5 deleted at 23k
I had piston 5 cracked in half at 38000. Mostly DD no load. went with heavy load on heavy tow. Kory Willis Tuning.
 
#35 ·
has anyone blown a motor with duramaxtuner tuning?
 
  • Like
Reactions: SeanScott
#38 ·
It has been great on all my trucks.
 
#39 ·
OT question: I see you ran the motorops tunes on your last two trucks, but now you have duramaxtuner. Were the motorops tunes too smokey? I would love to delete this truck for the sound and mpg, but that's about it.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top