Chevy and GMC Duramax Diesel Forum banner
  • Hey Everyone! Enter your ride HERE to be a part of this months Ride of the Month Challenge!
1 - 20 of 28 Posts

·
Registered
2017, 2500HD, LTZ, front guard, Duraflap mudguards, Leer bed topper
Joined
·
857 Posts
Discussion Starter · #1 ·
Tuesday my Duramax showed a CELand error code for a failing glow plug.
Also, 2 of my neighbors with Duramax had same failure..

what are the odds that 3 trucks, different years, would have this happen on same day?

ya think ONstare is drumming up service work?
 

·
Registered
2017, 2500HD, LTZ, front guard, Duraflap mudguards, Leer bed topper
Joined
·
857 Posts
Discussion Starter · #2 ·
Bumppppp
 

·
Registered
Joined
·
1,191 Posts
I see one is an L5P. What are the other 2 trucks? GM hasn't really been known for their excellence in glow plugs for the past several years now. I'd say you have to change them like spark plugs in an LML but they don't last as long as good spark plugs.
 

·
Registered
2017, 2500HD, LTZ, front guard, Duraflap mudguards, Leer bed topper
Joined
·
857 Posts
Discussion Starter · #8 ·
I see one is an L5P. What are the other 2 trucks? GM hasn't really been known for their excellence in glow plugs for the past several years now. I'd say you have to change them like spark plugs in an LML but they don't last as long as good spark plugs.
Mine and another L5P. And an LML. My 2017. A 2018 and 2015
 

·
Registered
Joined
·
6,390 Posts
Stop stealing each other's glow plugs🤣
 
  • Like
Reactions: cfell

·
Registered
2017, 2500HD, LTZ, front guard, Duraflap mudguards, Leer bed topper
Joined
·
857 Posts
Discussion Starter · #12 · (Edited)
A little different question... does anyone know if the L5P Glow Plug tips are ceramic? I have seen pics of some removed which appear to be missing some material...

Since my truck has started consuming oil, this is a concern to me, about what is happening inside the cylinder(s)..

Thanks in advance! R/S

UPDATE:
I found this:

also, several non Duramax similar problems with melted GP tips or just 'broken'.. There is no definitive reason they fail by the tip of the GP shattering.. could be defect, poor install handling, shipping damage, carbon deposit flaking off or coming into the cylinder and smashing into the tip... The general opinion is the debris is shattered and flushed out the exhaust. "HOWEVER" they also 'borescope' the cylinder to ensure there is no cylinder damage.. and look for the part bouncing around..

I did hear an unusual sound one day, but it cleared quickly (warmup idling in driveway).. I gave it no second thought at the time, thinking it was just exhaust expansion...

It has been noted on the forums here , somewhere, that the GPs are good for under 60K miles... This has been mentioned in other places in the Wild Wild World of the Internet as well.. paranoia???. yup. Don't need this stuff...

I have had aircraft engines, with less than 50 hours blow the jug off in flight.. and in an airboat application... it makes a really bad noise and spills your 'drinks'...
 

·
Registered
2017, 2500HD, LTZ, front guard, Duraflap mudguards, Leer bed topper
Joined
·
857 Posts
Discussion Starter · #13 ·
Bosch seems to agree.. they don't last.. and when one fails, they are all about ready to fail..
 

·
Registered
2017, 2500HD, LTZ, front guard, Duraflap mudguards, Leer bed topper
Joined
·
857 Posts
Discussion Starter · #14 ·
Just returned with truck from dealer.
applied update:
#20-NA-176 Reprogram of Glow Plug control module.
1087868
 

·
Registered
2017, 2500HD, LTZ, front guard, Duraflap mudguards, Leer bed topper
Joined
·
857 Posts
Discussion Starter · #16 ·
Is that the tsb from 2017?
the number begins with “20”.. does that mean 2020?

Service guy initially said 2019.. over the phone. I did not see anything about superseding a previous one you mention from 2017.

not much different than the 2017 TSB.. except engineering in the 2017 is seeking “information from the field”.. maybe the one they applied is the actual fix.
Can’t help but wonder “do they just turn off the failed glow plug” until several fail?

nah, that would be unethical.

 

·
Registered
2017, 2500HD, LTZ, front guard, Duraflap mudguards, Leer bed topper
Joined
·
857 Posts
Discussion Starter · #18 ·
First drive home the truck ran fine, 15 miles on D48m interstate… 70-75.. “Like buttah..”

Condition 1
  • 1/2 tank fuel, nothing in bed of truck
  • startup at dealer no problem or CEL noted
  • slight new “harmonic” sound and vibration.. subtle … except I know my truck pretty well
  • idle for about 90 seconds all good, same sound/vibe as mentioned
  • leave dealer and leaving stoplight gave a very little “jab”, get a little “pause” in engine..

Condition 2
  • continue Condition 1
  • enter superslab about a mile up as temp coming off the peg.
  • accelerates to posted speed on service road, no problem
  • temps up above 170-180(gauge)
  • Exhaust Brake on
  • tow-haul (TH) off
  • great performance.. but not yet discernible differences
  • speed 70 MPH.. (posted 75)
  • note DIC MPG once temp is 200+
  • throttle response slightly spongy… (probably a relearn after update)

Condition 3
  • continue from Condition 2
  • switch on Tow-haul (TH)
  • note MPG
  • note throttle response… not precise, but no stumble

Condition 4
  • continue from Condition 3
  • two miles letting traffic thin out.. then increase and decrease throttle, trans seems to release, engage the TCoverter (TC)
  • TC behavior settles to previous “feel”
  • release of throttle and apply light brake, EB kicks in
  • turn EB off, EB doesn’t engage with throttle/brake but transmission can be felt decelerating

Condition 5
  • Continue 4
  • TH and EB off
  • modulate throttle
  • deceleration is less pronounced, no tentative transmission feel
  • engage cruise… holds great on incline and decline
  • Check MPG during next 6 miles on Cruise

Condition 6
  • continue Condition 5
  • exit interstate and enter in town traffic, 40MPH, level for 2 miles
  • holds on cruise
  • turn EB and TH off and on, no change
  • turn in EB and let off throttle… different deceleration, more pronounced on brake apply (hmm, that’s a little different)
  • EB and TH on thru town. Throttle decel, definitely decel by engine and trans.. more when brake touched.

Condition 7
  • Continue Condition 6
  • 18 miles driven, many throttle and setting changes
  • at 35 MPH smooth and precise throttle response RPM stays about 1400 and doesn’t shift higher (same behavior as before)
  • vibe/sound not changing… varies with engine speed

Condition 8
  • continue condition 7
  • vary speed and idle into residence area.
  • no “lurching” as before when light throttle going downhill.. smooth
  • same sound from engine..
  • shut off engine as always…
  • end ride at home.

All in all, dealer said “we have never seen such a clean Dmax and you have used it! We found no oil anywhere around engine.. coolant held pressure.. we updated the GPCM and no check light or out of spec GP’s or engine sensors.”… “with regard to oil consumption, here is GM spec… but I don’t know why they say that… towing may (will) increase oil consumption.. as prolonged high speed (above 65).”
 

·
Registered
2017, 2500HD, LTZ, front guard, Duraflap mudguards, Leer bed topper
Joined
·
857 Posts
Discussion Starter · #19 ·
Update.. truck running ok.

there is no CEL.

Interesting, however, when I checked, the “permanent code” is still on the truck…

My understanding is the code will automatically reset once the problem is resolved.

Should I clear the code or return the truck to the dealer?
 

·
Premium Member
2018 Silverado 3500 LTZ Z71 L5P CCSB
Joined
·
221 Posts
I would recommend a tin foil hat.
 
1 - 20 of 28 Posts
Top