2015 GMC Duramax Diesel -- Update! See Post 17 for those curious

[lintesia]

I’m in the unexpected position of having to find and purchase a used truck. My beloved 2007 Chevy Silverado 2500 HD was in an accident and was totaled (no horses or horse trailer involved, fortunately). I loved the truck and intended it to be the only truck I would ever own.

But life happens. Someone at my barn is selling their 2015 GMC Denali – it’s Duramax Diesel, 3/4 ton, with about 115,000 miles. I would use it only for hauling my 3-horse GN trailer.

Does anyone have experience, positive or negative, for this era truck? Any red flags I should be aware of? TIA!

[endlessclimb]

Is it deleted?

How much highway vs city driving has it done? How much hauling?

[steelerino]

My boyfriend is a diesel mechanic and I don’t see many of them at his shop if that helps lol

[lintesia]

@endlessclimb

Is it deleted?

How much highway vs city driving has it done? How much hauling?

I’ll have to find out. I’ve been googling the “deleted” thing – am I correct in thinking that this means the emissions controls have been tampered with? I’m in CA, so that would be a no go if that’s the case.

[endlessclimb]

It could still be deleted, so double check.

Honestly the engines run better deleted, so if it was deleted but returned to stock for sale, I would be unconcerned. Lots and lots of cali guys run deleted trucks with sims in the sensors, allowing you to keep a stock look for inspections, and it’s easy plug-and-play to return it to stock if needed to smog - so, buyer beware.

If you’re buying from a dealership, it would not be deleted due to state law. If you’re buying private owner, double triple check that it’s returned to stock (make them sign something if you have to) before moving forward.

[endlessclimb]

Re: city vs highway…

These new trucks and their need to regenerate the diesel particulate filter (DPF) are NOT designed to only be driven in the city, nor are they designed to idle for a long time. Diesel Exhaust Fluid (DEF) is a big improvement on the original systems - the original systems needed exhaust gas temps (EGTs) in the 1000F+ range to properly regenerate, which is not going to happen at idle, or during city driving. The inability to regen causes huge issues in the DPF long term.

DEF allows for a lower temperature regen, but still - these are not trucks that you can have a diesel for funsies - they need to be worked pretty hard to run right.

[SusanO]

So making 200 mile hay runs on the interstate is good for them? And 150 mile towing trips? I will tell that to my truck.

[endlessclimb]

For the post-EPA diesels, that’s a resounding YES. They need to work hard to clear the soot out of that filter.

[cbg]

I have a 2016 one ton version of this truck (bought it in 2019 with 40k miles, now has 88k). Other than a problem with the DEF module the first summer I had it (a known issue, covered under warranty) I haven’t had any other difficulties with it.

I had the exact same 2500 as you before I got this truck, and so had to get used to carrying around boxes of DEF, but other than that I like this truck. The Denali has all the bells and whistles - heated seats and steering wheel, lights in the truck bed, backup cam, sunroof, etc etc so it’s comfortable on long drives.

[SeeSpotEvent]

We had this truck before we sized up to a 3500 GMC and it was great! Looks super and hauled like a champ for our two horse BP. We were very sad to sell it when we bought the big truck. No issues with reliability, we’ve had GMCs for years and very good luck.

[Calvincrowe]

I have this truck in the one ton version, and it has been fantastic. No issues, runs and hauls like a dream.

[LCDR]

If it still has its original batteries, they are living on borrowed time. For reliability and peace of mind replace them. Dual battery setups should be replaced together, even if just one of them tests iffy or bad, but you know that from your other diesel. And at 7 years old, the original tires are likely at the end of their lives too, so budget for batteries and tires sooner than later.

[CanteringCarrot]

If be impressed if the truck still had the original tires with that many miles on them. In fact, if the truck still has its original tires and they’re not dry rotted and/or totally bald, tell me which tires those are, I’m interested lol

Jokes aside, I think those are pretty good trucks. If the price is right, and it suits your needs, I’d go for it. Due to where I live I always look for rot/rust, but that might not be an issue for you depending which part of the state you’re in and if the truck has been there it’s whole life.

Inquiring re the delete is a good idea, and also the type of miles.

It’s been a few days now, did you make a decision yet?

[Aces_N_Eights]

I have a 2016 GMC 2500HD with the 6.6L Duramax. I haven’t had any issues(knock on wood). First Duramax I’ve owned after being loyal to Dodges with a Cummins.

I’ve always been told, don’t know how true it is, run the exhaust brake all the time to help keep the DPF and the turbo cleaned out. (Along with getting on the freeway and blowing it out)

[endlessclimb]

The exhaust brake will not clean out the DPF, but it is important to run it a lot to keep the vanes in the turbo from getting sooted up and seized. Note that it does put TREMENDOUS back pressure on the head, so I don’t run mine until I know the truck is within 20deg of operating temperature (for me, that’s 180F on the coolant). On my Cummins, the exhaust brake will exert 40-50# (!!!) of back pressure.

My routine is: Start truck, put in high idle, turn on exhaust brake (puts about a 10% load on the engine at high idle). Let it warm up to 100F on the coolant. It’s ready to drive, with a light foot and with the exhaust brake OFF. So, turn the exhaust brake off, drive easy until truck reaches 180F on the coolant. Now it’s ready to haul and be driven normally. Turn exhaust brake back on.

[lintesia]

Tires are new. No delete.

Pre-purchase exam this morning! I’ll keep you posted!

[lintesia]

Just wanted to provide an update. A few things came up in the PPE which would cost around $4k to fix. I made an offer that was $4k less than the asking price and my offer was not accepted.

I had also looked at 2007 Silverado 2500 HD (Duramax Diesel), almost identical to my truck which had been totaled. I had a PPE done on that and only minor things were found, all of which were promptly addressed by the seller. So, this afternoon I wrote the check and I’ll take possession on Friday.

When all is said and done, the truck I bought certainly doesn’t have the highest end touches of the Denali (but it’s still an LTZ so pretty darn nice). And I am supremely relieved that I won’t have to worry about the emissions issues that trucks of the Denali era one that I was considering seem to be plagued with.

I appreciate everyone’s help and input – thank you COTH-ers!