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LML CP4 Lawsuit

Will L.

Well-Known Member
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Boulder City Nv
The air pockets formed because of reduced lubricity...
I don’t think this writer describes the situations well, but we all know if I did it a book would ensue, so... haha

Hopefully gm and all other mfrs make the effort to not have this bite them in the future at least. I believe gm will walk clean of this unless those suing have some kind of a “Ivey memo” proving gm knew and opted to just save money. Even if so, it is their option to simply sell an inferior product knowing they have to eat a percentage under warranty. Caveat emptor...


Active Member
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I see tons of issues with the CP4s. I've probably condemned over 10 of them this year. And when they come apart they tend to take out the entire fuel system.

We have a L5P in the shop now that had ALOT of water ran through it. $30k to replace the entire fuel system. Insurance is covering it.


Lucky To Be Here
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Appalachian Mountains
This is the first L5P we got to tear into. Personally I would NEVER own one. These things are just stupid. And I thought the LML was a pain in the ass to work on. If you want a duramax get a LLY or LBZ.
Yelp, something years ago just told me to buy the 2006 LBZ. It was December 2005 the dealer had some left over LLY Trucks, but I said nope I want the LBZ, its got more power. So here I am I have the 2006, 2500HD crew cab 4x4, with about 87,800 miles on it.

I know a guy that has a white 2006 crew cab, 4x4, 2500HD, LBZ with only 20 some thousand miles on it. He only tows his 5th wheel camper around with it.


Well it hits on 7 of 8...
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This is the first L5P we got to tear into. Personally I would NEVER own one. These things are just stupid. And I thought the LML was a pain in the ass to work on. If you want a duramax get a LLY or LBZ.
I take a 6.5TD over an GM Uber screwup LLY Duramax overheater any day because the temp problems on a 6.5 are a known known and can be fixed. (Except for Hummers: they just expend the engines.) My modified cooling system 6.2 turbo IDI has drug many trailers through Death Valley in the 121 degree temps with the AC on. First (only and last) trailer I drug through Death Valley with that POS LLY overheater I had: it was a survival situation with the heater on high in 121 degree temps and nothing was cooling it down. The LLY had programming and the AFE intake elbow to help with known LLY design defects aka temp problems before setting out. No, backing off the throttle and manual downshifting to keep RPM up doesn't stop the temp runaway on an LLY when it decides it's going to pin the guages in the red.

Plenty of ideas and theories out there that one can test on an LLY, but, experimental and expensive $$$$... that's not your point of a reliable easy to work on Duramax. The LLY is the ONLY Duramax that has a deserved reputation of not being up to the job.

My LLY was a nice truck otherwise, but, Patch a 1993 6.5TD with a hybrid 6.2 turbo dropped in kicked it ass on a regular basis for hauling trailers in the heat. Even our LMM ran hot, but, got the job done with only minor loss of oil pressure alarms. If you just need to get the groceries maybe an LLY is right for you.


Staff member
Lead Moderator
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So far the L5P has been pretty solid. Banks is pushing some big numbers with them straight from GM(not the ones they have built special for them). It's just the next step of evolution of the DURAMAX design.