I have a buddy of mine looking at a 2013 Dmax. He asked what I thought of them, and I told him I wasnt really sure because I have never done any real research on them. He was curious about the DEF and how often he will be adding. How often are the Regen's occuring for a guy that doesnt drive his truck more then 30-40 miles a day on average? How to get 30+ mpg with a duramax? How has fuel mileage been on the average for you guys? Have there been any common failures with these late model trucks? I didnt have answers to most of his questions because I'm still running and figuring out my 03 still haha. Any input related, or not related to the above topics would be hugely appreciated. I told him Im sure he'd be happy with the purchase as he had an LMM a few years back. Thanks guys!
He'll like it. The duramax is entering its 20th year in production. That's a pretty good run. I have an 05 LLY with 240k on it. I've owned it since 08. I never had any issue with it. I average 17-18 mpg even after the square body swap. 30 mpg will never happen. Lots of internet rumors swirling about 20-25 mpg but I've never seen that confirmed. 20ish is a stretch. The def stuff is what it is. Lots of misinformation out there. If he deletes it, make sure he keeps it, as diesel emmission inspections are coming down the pipe.
I've had a Duramax truck ever since they came out. Currently driving a 2014 and my wife is driving a 2013. Also have a 2012, another 2014 and a 2015 in the fleet. I deleted my 2014 when it had 500 miles on it and I've never regretted it. People are always afraid of deleting the DPF because of the warranty coverage you may or may not lose. I never had any warranty problems whatsoever. The only problem with any of my other trucks has been with the DEF and exhaust systems. We went thru DEF heaters on a regular basis for awhile but I think they have that sorted out. Now it seems that we've reached the end if the life span for the EGT sensors. There's several of them, before the cat, after the cat and after the DPF. When you have problems with the EGT sensors the truck goes into a death countdown to limp mode. Nice to have a warning but you're afraid to go anywhere. 80 Miles to 65 MPH! Service Exhaust System Now! See owners Manual! Keeps flashing on the DIC (Drivers Information Center). Something else with this generation of Duramax that I've never had before is they develop oil leaks. The small, annoying, hard to find kind of oil leaks that spot your driveway and make a mess underneath. I've always heard and it seems to be true that if you drive a lot you'll be fine. If you only drive the truck 5 miles to work and back with no good long runs, you'll have problems. See, you need to build the heat up in the exhaust system. When it gets hot from driving the passive regens are automatic and you never notice them. If you do a lot of stop and go driving you are going to need regens on a more frequent basis. Some of them will be incomplete because they didn't have time to finish before you stopped the truck. I believe this leads to more build up in the DPF that will only come out if you do a forced Regen. And I can promise you'll use more DEF than you ever imagined. These trucks drink it! Overall I have no real complaints. They're good looking trucks! They drive great, they're nice and smooth.
Well, I've had three of them (2008,2012 and 2019). The 2008 was the first year of DEF and I was disappointed to see the mpg dropped from high teens, low twenties to 14 or so with the advent of DEF. Both the 2012 and 2019 have averaged roughly the same 14 mpg. I am pretty easy on vehicles...put 100k+ miles on both the 2008 and 2012 before changing tires and brakes. The 2019 is also at 14 mpg so 14 mpg is likely max you will see with DEF Duramax. I have to add 5 gallons approximately every 3-4 months. Trucks have been quite reliable, drive well, are comfortable and have plenty of power. I pull a pretty heavy(6500lbs unloaded) 23ft boat with ease. Regular oil changes are a must as with any vehicle. Fuel filters need to be changed every 25-30k miles and are on the expensive side if you have someone do it...they are kind of a PITA to do. The only repair complaints I have are I had to change the heater motor on both the 2008 and 2012 + I must have gone through at least 10 headlights between those two models. Although GMC won't admit it, I have to think there is a design/quality issue with heater motors and headlights. So far, the 2019 has been trouble free after about 30k miles. Overall, I like the truck and would recommend it. Hope this helps. Steve
