2017 Duramax Owners Report

[Hans627]

Any other reports on real world experience with the 6.6 L Duramax in a 2017 or '18 GM HD?

Thanks!

[wulfraat]

11k mostly towing miles on my 2017 L5P and no problems. Great match for my 30’ international.

[Tater]

Originally Posted by Hans627

Any other reports on real world experience with the 6.6 L Duramax in a 2017 or '18 GM HD?

Thanks!

We now have our 18 Silverado Duramax. We have 6,000 miles on it and had it's first oil change yesterday in Sheridan, WY. We are headed to Alaska so truck will have at least another 10,000 miles before returning to Florida. We are averaging around 12.8 MPG towing 2012 Classic fully loaded both truck and trailer. We have added 5 gallons of DEF when warning appeared. The dealer who changed the oil said they only needed about a gallon to fill it up. I'm not convinced they put the DEF in at all but we will see. So far, very happy with the truck and Duramax.

[wulfraat]

I’ve found that when towing the 7 gallon DEF tank will last maybe 3-4k miles before the light comes on. I fill it myself.

That’s how you know Chevy are not cheating on emissions with the L5P duramax - they dump an appropriate amount of DEF into the exhaust when the engine is under load.

[peggy2ten]

2018 GMC Sierra 2500HD Duramax 12k
Check engine light four times.
Third and fourth led to regen message that would not go off despite hours at expressway speeds AND then reduced power regime--nifty towing into Black Hills at 30mph.
Two visits to Rapid City dealer the last finding a GM bulletin: the engine plant had been misfitting a turbocharger pipe such that exterior air was sucked in; realigned by dealer.
Been to Salem OR rally and heading east since with no further problems.

[thewarden]

Originally Posted by ashrink12

I have a 2016 Silverado Duramax and I have had no problems with it whatsoever. I have about 13,000 miles and most of that is towing. I do have one question for Duramax owners. After each oil change my engine oil is almost immediately dark to the point of being almost black. This happens in a very short amount of time. I understand that there is a reservoir of oil that does not get changed when you change your oil and that this small reservoir can quickly darken the new oil. If anyone has any thoughts or knowledge about this matter I would appreciate it. I am just concerned that my oil is dark, almost immediately after having it changed.

Thx
Greg

Perfectly normal for a diesel. It is the soot which is a byproduct of burned diesel, which liquifies and makes the oil turn black.

[brick1]

My 2018 Ford F-250 has had no recalls...
brick

[jwpaquette]

‘18 Silverado 3/4 w/ Duramax. No issues as we approach 10,000 miles at the 4 month mark. Will need a fuel filter in a few months and another oil change and tire rotation. Aside from regular maintenance, the truck has run incredibly well. Has pulled our 30’ FC from Ohio to Florida, TN and Montana. With a 25 MPH headwind, mileage was down in single digits as we pressed through Great Plains states. Mileage returned to mid teens once the winds subsided. Without towing, mileage is in high teens, low 20s.

[ImaTarHeel]

I have a 2017 Silverado 2500 HD. Towed my 19’ Bambi from the guy I bought it from in OH back to East TN. No issues whatsoever, in fact it was easy to forget I was towing anything. Got right at 15.8 mpg on the towing trip! Very happy with my Duramax!

[GOUSC]

I have a 2018 Sierra SLT 2500 HD Duramax diesel with 4,000 miles and half of that towing. Only issue to date was a leaking pinyon(?) seal at the rear axle. Covered under warranty and no issue since then. MPG seems to get better with more mileage. I live in Mooresville, NC and picked up Globetrotter in Tampa FL. 18.5 mpg going down to pick up and 13 mpg towing back. Most of that was flat.

Since then I've moved up to 21.2 mpg for the full trip without towing to Mountains and back with a best mpg of 25.1 over a 50 mile stretch. Towing to mountains and back I get 14.5 mpg's.


Coming down eastern continental divide on I-40 from Asheville east the exhaust brake kept everything under control w/o having to use regular brakes. So far so good with no regen or DEF issues. I have a 5 week trip out West coming up in the fall that will be the real test.

[rocco52]

2017 Silverado 3500 Duramax, 18,500 miles. No issues yet. Software update about 10k ago changed the shift points to lower speeds. I like that very much. It takes better advantage of the torque. The only downside to the update is that it now does a Regeneration about every 400 miles. Fuel economy for entire 18,500 miles (I have never reset trip B) is 16.4 mpg which includes about 10k of towing the 6K 25FB.