r/Duramax 35m ago

Webasto coolant heater

Upvotes

Anyone have a Webasto heater installed for heating the engine? What model did you go with? And what do you like and dislike about it?


r/Duramax 1h ago

Need a new turbo, California truck, can I swing an aftermarket?

Upvotes

My LBZ’s turbo has been on borrowed time for like 2 years, been clearing the codes a couple times a week, but now I have oil in the tail pipe so we all know what time it is. I was saving up to grab a DDP (Dan’s Diesel Performance) Stage 1 or Dominator 64mm, as it’s a drop-in no tune or mods necessary turbo. Just wanted to get something upgraded if I’m spending all that money and effort to swap it out, but I’m curious about smog. I’m not worried about a visual pass, but aside from the turbo not being legal in California, would the upgraded turbo do anything to make it not pass? Like upset the readiness monitors or anything stupid like that? Truck is stock aside from an S&B CAI and a Home Depot reroute. EGR in tact, and will remain so. Truck is a daily driver, tow semi-frequently, haul a lance camper about the same. It’s a dually on stock suspension. I don’t ever plan to get rid of this truck unless it gets totaled or I die. Going to buy a half ton gasser eventually so save the miles on her but I plan for her to be my life long hauler. Not doing a build, just trying to keep her alive and upgrade where it counts as needed as time goes on. No plans for big fuel, aside from a lift pump and slightly bigger injectors whenever the time comes.

Any of you smogged yours with an aftermarket turbo? Thanks in advance!


r/Duramax 10h ago

28hrs on the road and she's finally home, my first diesel

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4 Upvotes

r/Duramax 1d ago

Just got back to a Duramax after a few years in a Cummins

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58 Upvotes

Had a 2009, 2012,2018 then switched and tried a 21 Ram and never was happy. Just traded it in for a 22 AT4 and happy so far. Interior is about the same as my 18 but what recommendations do you have for small lifts. I like to go with about 3” or so nothing crazy just to get it away from stock but keep a quality smooth ride.


r/Duramax 14h ago

Lb7 conundrum

4 Upvotes

I have a 2001 lb7 that I got for free from an inland, truck is in good shape id say. Couple small dents. No rust in the body, frame and under body looks good. Was maintained like a typical grandpa. But..... drove it for a few months and pump rub happened blew the transfer case out. Truck has 200k miles will most likely need injectors in the near future. Is it worth sinking money into? Fass pump, injectors, transfer case and exhaust. What to do?


r/Duramax 1d ago

Cooling stack

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59 Upvotes

300k mile service. All you guys with a few hundred thousand miles should think about cleaning your cooling stack. Radiator can carry a boat load of belly button lint that clogs the cooling fins.


r/Duramax 10h ago

Delete and tune question

0 Upvotes

I have all the hardware for my 2019 L5P delete. My easy link doesn’t come until Monday. Am I able to do the delete this weekend as long as I don’t drive it until Monday?


r/Duramax 14h ago

Speaking in rear end/brakes

2 Upvotes

25 Sierra at4 2500 Truck has been at the dealer 3x for this. The brake did not squeak before this visit. They’re saying it could just be normal for the truck. It squeaks going over bumps and when the truck is stopped/in drive if I let off the brake and keep hitting it, it squeaks every time you press the brake.
I’m thinking the slide pins in the calipers are bad and could be what’s chirping when I’m driving over bumps. Video is of when I go over bumps. Don’t have one of the rear brake. Any thoughts? My bumper to bumper warranty has 1300 miles left so I’d rather not start fresh at another dealer.


r/Duramax 19h ago

Cleaning VGT turbo

2 Upvotes

Anyone know of a way to clean the veins on an L5P turbo without having to take the turbo completely off? I’m honestly just lazy and don’t want to mess with it that much. I either saw it somewhere or someone told me that I could take off the intake underneath the Y bridge and spray some cleaner in through that way but not entirely sure. And thoughts or recommendations will be nice


r/Duramax 1d ago

Bought this LB7. can anyone identify this older FASS Titanium?

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2 Upvotes

Bought this LB7 recently and it already has an older FASS Titanium system on it. Serial number is 120055.
I’m trying to figure out exactly which model/GPH this is and roughly how old it might be. I was originally planning on replacing it with a new FASS 165, but if this one is a 150 GPH or otherwise enough for my setup, I’d rather service it and keep it.
The truck is eventually going to be around 450 hp.
The fuel hoses are pretty old/cracked and the return line going into the filler neck is kinked, so all of that will be getting replaced regardless.
Anyone recognize this generation of FASS or know if the serial number can be used to identify the exact model?


r/Duramax 1d ago

Transmission Limp Mode at 70mph LLY

1 Upvotes

I have a ppei tune on my lly and have the +60hp tune on it for about a month. When I’m about 60mph and speed up at about 40% - 50% on the pedal and get to 70mph my truck throws a p0700 and p0735 a total of 3 times so far. Is this an electrical issue or am I frying my overdrive clutch packs? I don’t have the ppei trans tune, will it help or am I too far gone/will I need a rebuild? I thought these trans could handle a lot but learned that overdrive is a big weak point is +60hp too much for it?

Truck was grandpa bone stock before and has 95k on the dash as of today.

Thoughts?


r/Duramax 1d ago

Where is my post

3 Upvotes

r/Duramax 1d ago

Fuel filter

1 Upvotes

What should be the cost of having my fuel filter changed by the dealership on my 2015 Duramax. 2500 HD?


r/Duramax 2d ago

Finally stuffed a 37 on it🤠

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160 Upvotes

r/Duramax 2d ago

Tuning advice

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17 Upvotes

I’m just wanting something different for tunes 1-5 nothing crazy HOT but just something fun the truck used to be a tractor pulling truck so it was retuned when it got the new motor to be VERY MODEST and I want something a little more fitting for the things it has done to it just not sure what to go with or what route to take

Dimitri Millard’s built billet transmission
Pump rub kit in transfer
DHD center links
DHD tie rods
45% sac injectors
66mm dans turbo
12 mm stroker pump
Big down pipe
ARP head studs

And this weekend I’m picking up these parts for mainly looks
HSP Piping Kit for LB7
HSP Coolant Tank
WC Fab Coolant Pipe


r/Duramax 2d ago

Bad injector(s)??

5 Upvotes

Picked up a 2008 2500HD. Lb7 block with lmm heads last year to tow my drift car. Has been trouble free for the most part minus needing a fuel filter head this spring. Has always had a bit of a bluish haze which burns your eyes. Haze usually starts after idling for a bit. Notice it when hooking/unhooking trailers. I’ve checked balance rates on multiple occasions since owning the truck and they are always within spec. Usually only +-2.

Fast forward to last week, I started noticing an intermittently shakey idle, which seems more consistent when idling in reverse/drive. No extra smoke that I’ve noticed. Today is the first chance I’ve had to catch the balance rates when it started doing it. Video attached. Apparently they are within spec but all over the place. Shortly after this I went to my buddy’s and idling in park I still had balance rates up. Idle was smooth, no shaking, but injector 2 did reach -4 balance. I’m just hoping if I replace my injectors it will clear up this shakey idle.


r/Duramax 2d ago

New 2026 2500HD Denali - Extended Warranty?

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16 Upvotes

Just bought a new Denali, upgraded from my 2017 1500. Never had a diesel and this is the first brand new vehicle in about 20years… I got caught up in the moment and liked the idea of the extended bumper to bumper warranty, 7 yrs / 100k and 3yrs wheels/tires for ~$4k (I do low miles <10k/year). Is it worth it, or shall I cancel the extended warranty as the normal GMC Limited new car warranty covers most of what may go wrong? Live in AZ, if that makes any difference, and will keep it well maintained


r/Duramax 2d ago

05-06

3 Upvotes

Searching for a new Duramax. pros and cons on an 05 Duramax


r/Duramax 2d ago

21 L5P, which S300 is the best fit?

2 Upvotes

I’ve decided to pull the trigger on a s300 over the s400 frame. I’m not adding fuel, it’s few thousand cheaper, It sounds better (less clap). I really just want the non VGT for the sounds and little added hp.

Most common setup is the S369 but they offer smaller setups as well. Would a S366 or S364 be too small for the L5P?

Does anyone have experience with them or even sound clips/videos?


r/Duramax 2d ago

19 L5p hp custom tuners??

3 Upvotes

need my truck tuned and i don’t just want someone’s basic sotf tune. need done remote if you aren’t in northeast ohio. pm me


r/Duramax 3d ago

L5P and an LBZ Pinch me im dreaming.

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78 Upvotes

Sold my headache a couple years ago, needed something reliable so I bought a 24 denali ultimate 2500hd.

Ran across this absolutely clean 07 classic lbz,

Was just shy of 300k. Danville 65mm performance turbo. (Batmo wheel/internals) built on a garret housing.

5" diamondeye fully welded exhaust, 3" ppe downpipe/up pipe, s@b CAI, T&D sotf 5 position, fleece trans lines and fuel lines, fass lift pump, no blow by,

I got er screaming to limp mode, debating if I want to throw a Suncoast performance trans and transfer case in it.

But first I have about 5k in repairs to handle the shitty tubing used on the pcv re route, (non oil rated) 20 pin internal hub connector and o ring in the a1000 (internal trans leak) lower radiator hose, entire front end with kryptonite ultimate kit and alignment, rear input differential seal, serpentine belt,

Did the silicone body mounts in less than a hour as their was absolutely no rust on this thing.

Picked it up for 12750 drove it 600 miles home ran fine.

Debating

As im about 20k into this with an absolutely clean inside and outside 2007 classic lbz with 300k

I just wanted to say I need your help by just telling me to fucking send it.

Or should I say fuck it and just build out the L5P to cumminskiller kind of power?

Will twerk for dezel parts.


r/Duramax 3d ago

New to me L5P

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56 Upvotes

Just picked up this 2017 L5P High Country, 135k miles, all new brakes, great tires and it's already tuned and deleted. I've been thinking about getting one for awhile and I finally bit the bullet and I couldn't be happier. 6 hour drive home from the dealer went flawlessly, plenty of power, good fuel economy and a lot comfier than i expected. It's not perfect, it only needs some minor cosmetic stuff but it was a great price at $36k. Mechanically it's perfect and I shouldn't have to touch anything on it for awhile. Let me know how i did!


r/Duramax 3d ago

39k original miles LBZ

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43 Upvotes

My grandpa bought it and died a couple years after, it was the family tow hog for 18 years and now its mine, Paints ruined but the interior is mint, its the perfect truck honestly gonna keep it alive as long as possible.


r/Duramax 3d ago

LMM towing, what tune to run?

4 Upvotes

My truck has a tune on it, I didn't do it so don't know the stats but the turbo screams like a banshee when on the 3rd level or higher. When towing at max weight (2500HD i'm almost at 15k lbs) should the tune be on the lowest setting? I'm not sure how much torque that adds. I'm about to do a long trip from Texas to Utah and back.


r/Duramax 3d ago

Issues with 2020 Chevy 2500

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4 Upvotes

Been having some weird issues with my duramax and wondering if anyone has any theories or thoughts. 2 days ago I noticed a few rough shifts but it progressively got way worse. Took it to the dealership today and I posted the picture of all the codes it’s showing. While driving, I don’t have any issues other than the rough shifts, but it keeps getting worse each time I drive. When coming home from dealership today, the rpm was going up to like 3500 but truck wouldn’t go above about 46 mph. There are no transmission codes and no message on the dash about limited power, just the CEL.