Gmc/Chevy 3500 Duramax feedback!

morinj · #1 09-29-2020, 08:52 PM

I’m interested in possibly making a purchase, monthly payment on a 2011-2015, or maybe a lease on something new! Looking for feedback or advise! These things are expensive but I believe you’re definitely getting what you pay for!

jstubbs · #2 09-29-2020, 09:35 PM

I would avoid a high mileage unit for the 11-15 years. They are notorious for the CP4 high pressure fuel pump grenading, which sends shrapnel that wrecks your injectors as well. About a $11K bill to fix correctly. Buy a 2017+.

skidderman · #3 09-30-2020, 12:30 AM

I have a friend who just traded his 2016 in for a 20. In 80 K the C3 pump went twice costing $7500 each time. The 17 model has a different system. I believe the C3 pump issue can be resolved by installing a Fass fuel pump.

j335 · #4 09-30-2020, 08:16 AM

I had a 2011, blew the head gaskets on it and mechanic told me they didn't have good designs in 2011/2012 along with years prior to mid year 2006 models. I went back in time and bought a low mileage 2010 as I believe the LMM's are the most reliable units next to the overpriced LBZ's. LMM is definitely not a work horse like the LML's which the different chassis, but I don't pull huge loads so not as needed for me.

As others have mentioned CP4 failures are there on the LML, pretty low chance though so I'd recommend googling away on them to get familiar with it.

4thredneck · #5 09-30-2020, 08:54 PM

Get a 2015 or newer Ford 6.7 and be done with it. May not get as good of fuel mileage but you’ll be happier.

jstubbs · #6 09-30-2020, 09:10 PM

Quote:

Originally Posted by 4thredneck

Get a 2015 or newer Ford 6.7 and be done with it. May not get as good of fuel mileage but you’ll be happier.

I am a Chevy guy and I would buy a new Ford diesel over any of the others in a heartbeat.

Albertacoyotecaller · #7 09-30-2020, 09:26 PM

I have had an 07, 13 and now on a 17.

Drive them in the oil patch for 5 years or 350,xxx Kms which ever comes first. Honestly been really good trucks with minimal issues, just the regular wear items such as breaks, tires, shocks, and some minor front end work.

amosfella · #8 09-30-2020, 09:59 PM

Quote:

Originally Posted by skidderman

I have a friend who just traded his 2016 in for a 20. In 80 K the C3 pump went twice costing $7500 each time. The 17 model has a different system. I believe the C3 pump issue can be resolved by installing a Fass fuel pump.

It's a C4.2 pump in that era. Most of those failures are fixed almost permanently by installing a modified C3 pump along with a proper lift pump. Merchant Automotive has a kit for that. But it's cheaper than replacing all the injectors and fuel system from the filter onwards. Plus the Cat 2 micron filters that most of the lift pumps use make the fuel system last a lot longer.

The C4.2 pump was just faulty by design it seems.

amosfella · #9 09-30-2020, 10:04 PM

Quote:

Originally Posted by j335

I had a 2011, blew the head gaskets on it and mechanic told me they didn't have good designs in 2011/2012 along with years prior to mid year 2006 models. I went back in time and bought a low mileage 2010 as I believe the LMM's are the most reliable units next to the overpriced LBZ's. LMM is definitely not a work horse like the LML's which the different chassis, but I don't pull huge loads so not as needed for me.

As others have mentioned CP4 failures are there on the LML, pretty low chance though so I'd recommend googling away on them to get familiar with it.

The LMM seems to be pretty good if it's emissions deleted. From a GM master tech in the diesel field, he said the the emissions equipment on the 7.5-10 was causing head gasket issues from the extra heat kept in the engine. Delete the emissions equipment from the engine, and he said it was the best years so far.

He did recommend studding the head down though if it had been driven extensively (150k+) with the emissions equipment installed.

j335 · #10 10-01-2020, 07:53 AM

Quote:

Originally Posted by amosfella

The LMM seems to be pretty good if it's emissions deleted. From a GM master tech in the diesel field, he said the the emissions equipment on the 7.5-10 was causing head gasket issues from the extra heat kept in the engine. Delete the emissions equipment from the engine, and he said it was the best years so far.

He did recommend studding the head down though if it had been driven extensively (150k+) with the emissions equipment installed.

Yes I've heard the exact same thing from another mechanic about LMM's. I deleted mine right away with a low tow tune, plan to keep the truck for a while.

Just looked at used diesels on kijiji, man nothing around I would get a price on new one ordered from factory before I dived into some of those prices.