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2017+ L5P reliability. Post good & bad

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2018GMC Senior Enthusiast

2018GMC

Posted
Posted

I’ve seen a few 2017 and 2018 L5P’s come up for sale private party.

 

They all have 7k - 10k miles. 

 

I know there will be some teething problems with an all new engine. 

 

Please post your good and bad experiences with the 2017+ L5P. 

 

Pics welcome!

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Waaazooo
Waaazooo

You know what I don’t like. That the DEF gauge in the DIC just has “Ok” until you get to the bottom 30%. It should have a scaled indicator like the oil life or fuel filter life. Just my .02 Sent

redwngr
redwngr

I still don't understand the fuss.   When it starts to give an % indication, it still has more range than the fuel tank. (and if the fuel tank is low when it gets to the 1000 mile def w

redwngr
redwngr

Fuss comment wasn't aimed at anyone in particular, just at the overall def gauge 'chatter', here and every other forum discussing GM diesels.       GM doesn't say use GM only.  Certainl

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redwngr Senior Enthusiast

redwngr

Posted
Posted

Nov 1 update should clean up most of the reported teething issues.

 

Some have had smell from burn-off at first regen, and a few are reporting smell later -- but reason and corrections are as yet unreported. 

 

I'm pleased with mine.  It had the updated programming when built and has been problem free.

480Ruger Enthusiast

480Ruger

Posted
Posted

I’m curious myself.  Just ordered one Friday.  Love my 16 except for the steering going out 4 times in 22,000 miles.

Waaazooo Senior Enthusiast

Waaazooo

Posted
Posted

I have about 7k miles on my l5p and this truck feels much better than my 1500 and my conworkers Ram 2500. I average about 16-17mpg when I commute. I tow a 34’ trailer and it’s a breeze. This has been a really good experience so far


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2017HD Enthusiast

2017HD

Posted
Posted

9600 trouble free miles. Had the dealer do the ECM TCM re-flash - did not really notice any changes. My daily drive to work just get it warmed up to operational temp - but I have noticed about once a tank full it does a re-gen. The exhaust gets hot and smelly - but I have yet to get the "drive more" message. It seems like the regen is able to start and start at will.

 

I saw a video where Gale Banks did a tear down of the L5P and from what I saw and what Gale said these new engines are well built - Gale feels that there is 20% more in the engine without much work - including the bottom end. They also tore down the top end and it was equally impressive.

Waaazooo Senior Enthusiast

Waaazooo

Posted
Posted

You know what I don’t like. That the DEF gauge in the DIC just has “Ok” until you get to the bottom 30%. It should have a scaled indicator like the oil life or fuel filter life. Just my .02


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FreeAmerican Enthusiast

FreeAmerican

Posted
Posted

I got mine in June,  z71 4x4 crew.  Bought it to pull our camper, so reliability was a concern for us and I was a little worried at first.  I had a CEL for the emissions that kept coming back.  I did have some frustration but it was more with my dealer and their lack of knowledge on the new engine.  

 

But it turned out to be a pinched wiring harness that broke through the wire's insulation.   They replaced the harness and that was it.  I did get ECU and seat belt recall done.  The ecu did seem to help drive ability and my commute millage went up a little. 

 

But no other problems and I am very happy with my truck.

KMGZ400 Senior Enthusiast

KMGZ400

Posted
Posted
3 hours ago, Waaazooo said:

You know what I don’t like. That the DEF gauge in the DIC just has “Ok” until you get to the bottom 30%. It should have a scaled indicator like the oil life or fuel filter life. Just my .02


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I agree with this as well, I dont know GM couldn't put at least a percentage meter for the DEF fluid

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redwngr Senior Enthusiast

redwngr

Posted
Posted

I still don't understand the fuss.

 

When it starts to give an % indication, it still has more range than the fuel tank.

(and if the fuel tank is low when it gets to the 1000 mile def warning, it's highly likely that there will be 2 fuel stops before adding def is a must do)

 

The '11's didn't have one at all, and it wasn't a problem to 'manage. 

When the 1000 mile warning occurred, simply put 'get def' on the to-do list. 

 

It was really no different than obtaining/adding windshield washer fluid when that light came on. 

 

DEF was harder to locate in late 2010 and early 2011 than it is today. 

Now, it's available at pretty much every high volume diesel location and at almost all auto part supply places.

 

  • Like 2
Waaazooo Senior Enthusiast

Waaazooo

Posted
Posted
I still don't understand the fuss.
 
When it starts to give an % indication, it still has more range than the fuel tank.
(and if the fuel tank is low when it gets to the 1000 mile def warning, it's highly likely that there will be 2 fuel stops before adding def is a must do)
 
The '11's didn't have one at all, and it wasn't a problem to 'manage. 
When the 1000 mile warning occurred, simply put 'get def' on the to-do list. 
 
It was really no different than obtaining/adding windshield washer fluid when that light came on. 
 
DEF was harder to locate in late 2010 and early 2011 than it is today. 
Now, it's available at pretty much every high volume diesel location and at almost all auto part supply places.
 

If you’re going to go through the steps of having a warning and reminder system. Why not just have a gauge? My DIC will tell me when my fuel is running low, but also gives me a gauge. Added that GM throws the “only use ac-delco def” but I have to order it for my convenience because my dealer charges $20/jug versus 12.50-13.00 from amazon.

Yes DEF is available everywhere... as is gas; however, there are plenty of places I wouldn’t trust buying fuel for my ex wife’s dads lawn mower.


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redwngr Senior Enthusiast

redwngr

Posted
Posted
34 minutes ago, Waaazooo said:


If you’re going to go through the steps of having a warning and reminder system. Why not just have a gauge? My DIC will tell me when my fuel is running low, but also gives me a gauge. Added that GM throws the “only use ac-delco def” but I have to order it for my convenience because my dealer charges $20/jug versus 12.50-13.00 from amazon.

Yes DEF is available everywhere... as is gas; however, there are plenty of places I wouldn’t trust buying fuel for my ex wife’s dads lawn mower.


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Fuss comment wasn't aimed at anyone in particular, just at the overall def gauge 'chatter', here and every other forum discussing GM diesels.  

 

 

GM doesn't say use GM only.  Certainly not in print in the owners manuals.. 

They say "can " be purchased at a dealer and then go on to suggest other locations.

 

The manuals also say:

"Use only DEF that is GM approved, or fluid containing the API certified or ISO 22241 label.
The use of other fluids could damage the system, requiring costly repairs that will not be covered by the vehicle warranty." 

 

Pretty much like every other fluid.  Use our brand or any other that meets the spec. 

 

I've never yet seen or heard of any DEF that is not ISO 22241 certified.

 

If anyone is aware of any, please post the info.

 

 

 

  • Like 2
2017HD Enthusiast

2017HD

Posted
Posted

I will have to agree that the one and only time the DEF low indicator came on for the 1000mi warning I was near the middle of no where and had just fueled up. I thought I could make it back home with my trailer without another warning - I was only 150 miles from there. However I got about 75mi out and the second warning came on, by the time I got home it was threating a slow down. Added 5gal of DEF and all was good. Dealer topped off the tank at the first oil change - have not added any more since.  I suspect that my selling dealer did not fully fill the tank upon delivery.

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m5guy Enthusiast

m5guy

Posted
Posted

Almost 23,000 relatively trouble-free miles.  Have experienced the following problems:

  • Low coolant warning message - Leaking lower tube and three service trips to get "air bubble" out of the system
  • Emmission code - required replacement of DEF tank (sensor problem in tank)
  • Minor surging and slow speed drivability issues - resolved by ECM flash in November/December

Love the power levels and lower noise from the L5P versus my previous LML's.  Overall positive experience with this truck.  Only two things I don't like:

  • Regens - very noticeable (higher idle) and always a burning chemical smell if I come to a stop - drive thru's are the worst if you have a regen underway - have not raised issue to dealer
  • Lack of some more modern features (heads-up display, push button start, active cruise, etc.) which should be resolved in next generation model

Overall, I would buy this truck again.

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