Duramax knocking at idle. All 6600 Duramax™ diesel engines have this condition; however, some are more audible than others. When reved up the sound gets better but as soon as it gets back down near idle rpm it gets very loud. I originally thought injectors, and read the balance rates. It only happens at low RPMs and speeds of 15-35. Would a stuck injector cause it to knock extremely loudly and idle so roughly? I did not see any smoke but at the same time I did not leave it running long enough to look. Advance to timestamp 21:40 to view. Right after I bought the truck it started knocking bad and smoking a blue smoke out of the exhaust. Duramax Diesel Warm Engine Idle Knock Sound – TechLink (gm-techlink. Have approx. It's quiet/non existent at an idle. 6 LML suddenly began producing a loud knocking sound that I can hear through the air intake. Had GM replace all injectors 14 months ago. 6L LB7 Duramax Problems and how you can fix them. Jan 5, 2025 · Knocking/Clacking Sound bad idle knock Jump to Latest 1. 0 diesel truck, going on 2k miles. I hear it only on acceleration. Oct 4, 2021 · Brand new ‘21 Sierra Denali 3. I took the chevy dealer duramax mechanic out with me, very nice and not cocky one bitafter listening to it for couple of miles, he was pretty confident, although not fully certain, that it was an injector knock and suggested he put the scanner to it to determined which injector was fouling. |Yes and you'll hear the notorious injector knock. Cyl walls look good. When the engine starts to warm up after about 10-15 minutes of driving it has a subtle knocking sound. Stock injectors. No fuel smell in the oil. Brand new ‘21 Sierra Denali 3. I have a rod knock and scared it's got in my crank and rods cause there's alot of metal in the oil Discussion about finding a good place to Customers may also comment about hearing a tick noise inside the vehicle at idle such as when sitting at a drive through window. UPDATE: Diesel fuel additive has eliminat My lbz knock s at cold idle when injectors are dirty. Dealer said they all sound this way. I will be postin them later, but as far as i remember, there were a few in the 3. My truck was purchased new and currently has 3800 miles on it. Check for worn or leaking fuel injectors causing uneven combustion. 0 diesel it runs rough and has a knock type sound. Hi all, I’m new to the forum and also to the 3. Temperature is cold around freezing . I. I purchased a truck a few months ago. Seems to be only at idle when I can hear it. Picked up my LM2 end of January. How reliable is GM's 3. The last number will indicate what cylinder. Not badly mind you but you can feel it. After a minute or so the knock goes away and the engine smooths out and idle speeds up So this morning I went and started my truck after it sat for 5 days. In gear it is noticeable as well when the RPMs break 1,500 +/-. The noise then went away Started the truck yesterday and noticed the idle sounded off and that truck was shaking. If the knock doesn't go away, it's likely mechanical issues like a bent, cracked, or broken part. It will go away with more load and around 2000 LLY Duramax often faces intermittent engine knock and fuel injector-related noises during city cruising. I'm not sure if I should of posted this in the tuners/performace section or here. The old girl has 376000 plus on her and over 200000 on the injectors. Assumed, it was potentially normal as the engine continued to break-in. It does not knock when you raise the rpm above 1500. Find video that shows how to isolate fuel intake and return lines at 'quick' disconnects by glow plug relay assembly. Canada: Dealers can review TAC Talk 52018. But the knock is getting progressively worst. I swapped in 4 new injectors on passenger bank with no change. Went back in to the dealer before I even left the lot and saw the service advisor and the diesel tech Nov 14, 2019 · Just traded my 2018 2500 Duramax for a new 2020 2500 L5P and notice a throbbing sound at idle when the engine is warmed up ( currently 2200km). 0L Duramax can stem from low-quality fuel, carbon buildup, or timing issues. Has performed flawlessly until yesterday when, upon departing a parking area, a very loud engine knock developed during mild-moderate acceleration. 2005 lly 240k miles. ok well i have been noticing a little bit of a knock not very loud but if u get out at idle you can hear it a little, and when im in the throttle about half at around 2k or so it knocks, only at high rpms. I have a really hard time believing that GM would consider this knock "normal". But it has developed a knock. Piston protrusion is all within spec. Can it be assumed that this noise was not there prior to the injector replacement, or was it also making this off idle knocking prior to the injector replacement? Hey does anyone else experience a ticking sounds outside your truck under the passenger side when its parked at an idle? My truck does this periodically I've noticed when I hop out after driving it. The nine most common LB7 Duramax problems are LLY motor ran great yesterday. Last week I had a knocking or chatter noise from the engine bay at idle. 6L Common Engine Noises Information Tip: United States: A description of these noises and an audio file of what they sound like can be found in: 2018 SKH Seminar Feb Emerging Issues #10218. Fueled it about a week ago and it’s just over 1/4 tank. However, it has continued to get worse. I am assuming an injector knock, but unsure. 6 trucks and still have a 16 Denali 2500HD with 209k miles that was put on a diet. Does not happen during acceleration or Gordy 424 & and I have been working on his LLY. Used to these things idling nearly dead still or at least my previous DMAX have including the 2017. Love it. I’ve Owner alarm over the sound won out, so the engineers at DMAX and GM Powertrain reduced the engine's oil pressure in later generations of the Duramax 6600, which seemed to help with the odd noise. Also, when I'm cruising in overdrive if i give it throttle and get the turbo spooled up then ease off slightly there is a rattle or knock. Sounds like a gas engine with low octane fuel. Engine knocking in the LM2 3. I just pulled off the interstate into the rest area and when the rpm came down to idle, it started knocking. I have a Knock on the drivers side. It doesn't go away until engine is warm. Backing off the throttle resulted in the loss of the knocking. I love the truck and I am trying to learn what is normal for this specific engine. As I put my foot on the brake it drops to normal idle and goes away, then won't come back until the next Alright I need help. Fuel burns late causing knock. Knocks at idle and during accleration. Unsure if it’s okay to drive short distances or not but don’t want to mess anything up too bad if I can Video: LBZ knock and rough idle Jump to Latest 4. Engine build variation from engine to engine contributes to differences in perceived volume. It happenes when I let off the Well driving home tonight on the freeway I noticed my truck sounding a little different than normal, well when i got off the freeway and it went to an idle it sounded horrible, sounded like a nasty knock with a grinding noise but as soon as you start to put a load on it, it goes away Some 2020 Silverado 2500HD/3500HD and Sierra 2500HD/3500HD trucks equipped with the 6. Anyone else? It is loping at an idle sometimes worse than others and on occasion after driving for extended periods of time it will idle smooth. this is my first diesel and i was told ill have to get used to the sounds of it and i My LLY has a pretty loud knock under acceleration/cruise, the more im on the pedal, the louder it gets. Knock caused because injection is not atomized at idle'drippy'. 2 in gear and warm with the rest below one. 5K views 6 replies 2 participants last post by mijdirtyjeep Jun 27, 2018 C I'm new to the form, Just bought a new 2011 duramax as a leftover this spring. I’ll be putting the My 21 denali 3l makes a engine clacking noise just before it shifts up to 4th gear rpms low ,if I give it a bit more gas higher rpms it does not do it ,runs great just makes the clacking or diesel noise ,don't remember if my 2020 3l did it ,sorry if it's a dumb question lol. Began having what sounded like valve clatter around around 2k rpm. Does anyone know what this is or have any of Where would be a good place to look about a reman motor. Truck ran great on the road but now at idle it has a loud knocking. Not a normal sound. Could this be the FPRV? What are the other culprits? Hey everyone! I’m brand new in the diesel world and just bought my first diesel. I came up this hill and thought I'd floor it just to feel the power. The trucks starts fantastic then goes into high idle. On the highway is was fairly quiet. Check for proper fuel octane and clean fuel injectors to prevent deposits. 02V. When I start it from cold I don't notice it at all, but when it warms up it comes right back. Went and drove it and it drives great, no smoke , no knock above idle. Inspect the EGR valve and intake for carbon accumulation causing uneven combustion. The dealership has opened a "Tact" case no answers at this stage I have a 2007 LBZ with 140K, and it has been knocking on and off at idle and under light load. 6L, but this is not the ticking or cycling that I have Customer: Hello, good afternoon. So that is a Thumping sound heard at idle and increases with RPM as you drive. Anyone else? Mar 3, 2020 · PIP5711 2020 6. Start off by saying the truck runs and drives good. com) Duramax Diesel Warm Engine Idle Knock Sound April 15, 2020 Some 2020-2021 Silverado 2500HD/3500HD and Sierra 2500HD/3500HD trucks equipped with the 6. Started it this morning to go to work and it’s now knocking. However the motor has developed a loud knocking noise. I checked the balance rates with my v2 and one was 1. I have a 2002 2500HD. 0 when warm and accelerating from a stop. We left for our up north camping trip, towing our 9500# travel trailer, halfway through the trip the motor started making a knocking noise, not a constant knock but periodic noise, it would do it when I was coasting more with limited throttle to keep my speed up, when I accelerated hard it would While running, disabling injector 3 changes the pitch of the knock. It sounds like a rod knock but would one let go out of nowhere? Do these injectors stick with no warning? PIP5711 2020 6. Truck had Information on Duramax Diesel 6. . And has a rough idle. Dealer says it's normal, and that there is a bulletin on it. It will not come out of idle. 0 Duramax. In park at about 1,500 RPM I hear the knock. Pop the hood and you can see the engine shaking. Check engine light is on. Issue is intermittent, doesnt do it on all start ups. 5's in drive and one around 7. Dealership says it is covered under the #16-NA-32 Bulletin on common engine noises Duramax 6. Light exhaust haze at idle, scanned to check injector balance, believe I have a fuel knock, trans code on dash for range Yes absolutely it can! Most likely it'll throw a p020? Code relative to it. Can hear it easily when standing outside front or when listening near front wheel wells and from inside the truck. So just replaced the fuel pressure regulator, truck starts better, doesn’t lope at idle anymore but the rail pressure at idle is unbelievably high, goes back down with throttle but just seems to get 4200 miles on truck and while sitting in the seat the truck is shaking. 0L Duramax? Read about common problems with the LM2 Duramax such as injector, HPFP, and EGR failure, and more. I thought great a stuck lifter maybe. If there are any old school gas guys out there, this sounds just like a chevy 350 C. 03D-0D March 2018 — Powertrain segment. Kinda like a LB7 does with bad injectors. The knocking sounds Subtle and short lived engine knocking in a 2021 Silverado 1500 Duramax 3. Upon acceleration, the engine makes a pinging or knock noise. My problem is I have a knocking noise that I never noticed before. 3K views 5 replies 3 participants last post by Hate2looz Jan 6, 2025 Feb 22, 2020 · :confused: Hi everyone. No codes, no check engine light. 6L, but this is not the ticking or cycling that I have New to the forum. Of course, the truck stopped making the noise before I drove I bought my first duramax. NO CEL!! If I drive at say 5mpg A forum community dedicated to Chevrolet and GMC diesel truck owners and enthusiasts. It usually subsides after a few minutes but its an early concerning issue I've picked up on in my '17 Duramax (duh!) w/only 7,100 miles, purchased at 4,700 miles. We had the injectors tested, and cleaned, and are within factory specs. When the noise first became present, I stopped at a truck stop and poured in some Lucas injector cleaner. At idle I don't even notice it. Just signed up to the forum. Comprehensive guide to 6. No drop in gas milage. Oil level was good and there was no blowby so I added a Hey guys, just bought my 1st NEW Duramax (EVER) and have a question. There's a knocking noise from the engine. This is my 4th Duramax so I am familiar with all the ticking noise complaints but this is not a tick. Does the new models have a different sound to them? It is hard to describe Hi all, first post. I traded my 18 canyon duramax in last December for a 2021 1500 elevation. It has this weird non-rythmic knock only at idle. It has an Airdog 150 I installed with the injectors and run additive and Just traded my 2018 2500 Duramax for a new 2020 2500 L5P and notice a throbbing sound at idle when the engine is warmed up ( currently 2200km). I picked up my 2020 Denali 2500 hd duramax this week and noticed a loud knocking at idle which increases in volume as the engine warms up. ATL Diesel's expert advice on how to fix the knocking sound in any diesel engine, ensuring smooth operation and reduced engine wear. My Duramax 6. 9 owner and that truck was really only loud on idle. The truck is running, but now we have an intermittent knock at idle. OK the other day out of the blue the engine developed a loud knock. Stumped. I’ve noticed When i start my 2022 yukon slt with 3. Then all of the sudden a large knock developed in the engine. He could use His Tech II or other good handheld diagnostic reader and turn off injectors one at a time to find the one knocking. Switched from being a hard core Powerstroke guy, to the D-max a few years back, and I really don't Information on Duramax Diesel 6. When I get in the truck I have heard a knocking/thumping sound (consistent with RPM) in the cab towards the center of the dash. piston slap or crank bearing knock. 8,000 miles on my 25 Silverado 1500 with the baby max LZ0. Come join the discussion about duramax engines, performance, builds, modifications, classifieds, troubleshooting, maintenance, and more! This occurs at idle and may seem to be louder when standing just behind the driver’s front wheel. 6L Duramax diesel engine (RPO L5P) may have a thumping or knocking sound coming from the rear of the engine. When truck is started hot or cold (doesn't matter 70psi oil pressure or 30psi) it knocks like a ROD knock at idle same sound everytime. 6 L5P Duramax Warm Engine Idle Knock Noise Models Correction: The noise described in this communication is audible in the interior and exterior of the vehicle but is more pronounced in the interior. At 1000rpm and light load, it shows up. I was towing my horse trailer about 7K# about 250 miles, upon returning home, I noticed the knock showed up. I now have the engine out and down to a short block. The surge is likely from the FPR causing rail pressure to rise at idle. The only time it doesn't knock is when you coast down hill Hello, My brand new l5p has a nasty knock at idle. It shoots and gets when you step on it and kicks out black smoke. Balance rates have been fine. When I got off of the highway I noticed a rotational knocking. The knock is rhythmic, always the same and is consistent with rpm. -Aaron- Need LB7 Injectors? Check these prices out! Just bought truck and haven't even gone thru a tank of diesel yet. Figured it’d warm up and stop but it did not, drive to Walmart and could notice it while driving also. I cannot hear this same noise outside or under the truck. I have an issue with my 2014 LML. Use clear 1 gallon container with your preferred anti carbon injection cleaner. Checked balance rates and surprisingly they are all within 1-2 2. My LB7 daily has developed a knock at idle and low rpm. The truck is a 2023 GMC AT4 HD! Have owned many used high mile 6. I have got an 05 duramax with 165k miles. I am a former cummins 5. The truck has 5000 miles on it. Intermittent clatter at about 24% throttle in the 2004. It didn't happen while driving it happened immediately after restarting from a trip to the store which was about 40 mins on the highway. 5 LLY Duramax can stem from injector issues or fuel pressure irregularities. The noise may be more noticeable in the first 20% of engine oil life. I got a pre-owned 2022 Silverado 2500 with about 50k miles. My DMax is the opposite. fpd03z, om1wb, 1w9t, oqb4z, pesvp, 5m7zu, pmb5b, ie8kg8, 2biv2, bdtm,