More LM2 Duramax 3.0 Issues - Chevy and GMC Duramax Diesel Forum
2020+ LM2 Duramax Powertrain Discussion of components that are directly involved in the power production and all that is needed to get and keep the truck moving . Engine , Transmission, Etc.

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post #1 of 2 (permalink) Old 01-14-2020, 06:01 AM Thread Starter
Join Date: Jan 2020
Posts: 1
Unhappy More LM2 Duramax 3.0 Issues

I bought a LM2 duramax recently, a black RST. I really do like it, but it has problems.

First problem: After getting off the highway and stopping at a light, exhaust fumes flood the truck through the air vents. I thought maybe it was just one of those new car smells, and I thought it might go away, but nope. But it doesn't really smell like a fresh messy oil change, and my when I took my GF out we both felt sick. Now the windows stay down.

Second problem, just a lot of weird engine rattles to pay attention to when applying the gas, sounds sort of like injector problems. Power can feel inconsistent from one half throttle pull to the next, but it doesn't feel like it's stuttering or anything.

The good stuff? Interior noises, there are 0. I have had a ton of new cars Audis/Fords/Toyotas/Bmws/multiple challengers/hellcats, this is one of the best interior experiences as far as no random interior rattles. The inner door panel could use some work though, it creaks and feels cheap when you use the inner handle.

Hope a dealer can fix it without tearing it up, but I think she's probably not going to make it out unscathed.
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post #2 of 2 (permalink) Old Yesterday, 11:51 PM
DiNoto's Avatar
Join Date: Feb 2020
Location: Southern Commiefornia
Posts: 1
Just checking in to see if you had a chance to have your truck checked for those engine noises. I have been having the same issue. This is my second diesel truck and I am a big fan of diesel clatter and injector noises and all of the diesel goodness. That said, I am having unusual combustion noises like irregular pings and cylinder rattles. Really noticeable when in a regen. I am also having excessive regens (every 150 to 250 miles - when manual says it should be approximately once per tank of fuel). My fuel economy isn't that spectacular either. I am averaging 25.3 mpg on my 2wd that is rated 23 city / 33 hwy. In contrast, my '16 Colorado with the 2.8 Duramax was averaging 27.1 mpg with 91k miles and was rated at 31 hwy mpg. I drive them both the same, but get worse fuel mileage. I have been reluctant to take this in for service because it isn't throwing a code. My unfortunate experience with Chevrolet service is that if it isn't throwing a code and they don't have a TSB, the techs are completely lost and cannot diagnose problems. Hoping you had good luck that you can share.
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