Duramax 3.0 Complete Tear Down

[Xring01]

I have been watching this guy on youtube for a few years now.
He does complete tear downs of engines.. pretty much all of them for the most part.

You can fast forward to the 27minute mark to start seeing the damage… and the last 3-4 minutes he reviews what he thinks caused the failure.

However watching him tear this engine down, gave me more respect for DM 3.0… I will still not own one due to the oil pump belt which I have covered on the many threads of the DM 3.0.

This appears to be a well built diesel. The reason this one failed, appears to be low oil, at 146,000 miles.

 

[DarkHorseRacing]

This is for the older 3.0, correct? The LZ0 hasn’t been out long enough? Did they fix the belt issue in the new version?

 

[OCMerrill]

This is for the older 3.0, correct? The LZ0 hasn’t been out long enough? Did they fix the belt issue in the new version?

Thats correct, this is the LM2. Lack of oil pressure and this early engine consumes oil. The LZ0 has many improvements but shares most of the LM2.

I think its a pretty good engine myself.

I Do Cars is the youtube channel. He does midweek attempts to get certain cars he buys at auction running which I also find entertaining. He loves BMW's but damn when those things go bad they really are a challenge.

 

[JFMFG]

2021 gmc with 3.0 do I need to worry about this oil pump belt?

 

[DarkHorseRacing]

2021 gmc with 3.0 do I need to worry about this oil pump belt?

I dont think you have to worry about it per se, but save up your cash when it needs to be replaced as it’s pretty extensive labor getting to it.

Good news is I believe it’s a high mileage replacement item so not very often.

 

[JFMFG]

I dont think you have to worry about it per se, but save up your cash when it needs to be replaced as it’s pretty extensive labor getting to it.

Good news is I believe it’s a high mileage replacement item so not very often.

I plan to run this one between 150k-200k before I pitch it. I’ll roll the dice. The labor to repair will be cheaper than a new truck in 6 years lol

 

[Xring01]

2021 gmc with 3.0 do I need to worry about this oil pump belt?

When the DM 3.0 first came out. The recommend maintenance on the oil belt was to be replaced at 150,000 miles.
I have mentioned that on many of the DM 3.0 threads on RDP as the key reason I would not own one.

Because you have to remove the tranny and then dissemble the back end of the engine just to get to the stupid part that has to be replaced. Think about how many hours of labor thats going to be and more importantly COST…

I plan on keeping my trucks alot longer than 150,000 miles…

Thats what I stated prior to watching the above video.

This video clearly shows what the belt looks like at 150,000 miles, and all the work involved in replacing it. IMHO the DM3.0 appears to be well built engine…. Now that I see how it was all built… Why in the fuck are they useing a belt, when they could have easily installed a chain.. thats freaking stupid from the engineering design aspects.

Creating a huge cost maintenance item or a potential failure point… when all they had to do is change a few components replace a stupid belt with a chain… I am dissappointed in GM for it. They lost credibility in my eyes over that design FLAW.. fucking stupid.

 

[NeedlesRat]

I plan to run this one between 150k-200k before I pitch it. I’ll roll the dice. The labor to repair will be cheaper than a new truck in 6 years lol

Do you use this to pull your Magic, and if so how does it do? We have a Mach 26 and interested in the 3.0DM for the little amount we tow it and the possibility if we wanted to do longer trips towing the boat, or towing across the desert to bring the boat home from the river if needed.

 

[OCMerrill]

What makes diesel engines last is gear train. Chains and belts both build maintenance intervals.

Down side is its noisy and I am sure what GM was trying to avoid. Dropping a trans? I agree that's a bit much and a maintenance item like this should have been in the front.

 

[JFMFG]

Do you use this to pull your Magic, and if so how does it do? We have a Mach 26 and interested in the 3.0DM for the little amount we tow it and the possibility if we wanted to do longer trips towing the boat, or towing across the desert to bring the boat home from the river if needed.

Yes we do. We only tow the magic short distances in havasu but honestly it does well. You feel it slightly at takeoff but cruising speed everything is there. I made the mistake of wanting to save 1k on shipping earlier this year when my new catalogs for work were done since the printer was only 40 mins away and WAY WAY WAY overloaded the truck. I’m talking 12k lbs of catalog plus 24ft enclosed trailer weight. Truck pulled it again no problem sluggish off the line but cruising and obviously stopping with electric brakes on the trailer zero issue. When I do day trips to the desert I’ll have the enclosed trailer with can am, and dirt bikes in it and it’ll do everything and more I want it to. So for your Mach 26 I think there wouldn’t be a better move. I didn’t need the 2500 this go around since we have a motorhome now so the 1500 was ideal for me.

 

[Bigbore500r]

This is for the older 3.0, correct? The LZ0 hasn’t been out long enough? Did they fix the belt issue in the new version?

They didn't change it, it's still the same design for the oil pump. But that being said - this motor has 150k on it and the belt looked decent. The fact you have to drop the trans to get to it sucks balls though, still the case

 

[Xtrmwakeboarder]

They didn't change it, it's still the same design for the oil pump. But that being said - this motor has 150k on it and the belt looked decent. The fact you have to drop the trans to get to it sucks balls though, still the case

But they did increase the interval to 200,000 miles on the LZ0

 

[Bigbore500r]

But they did increase the interval to 200,000 miles on the LZ0

Yea, probably because the belt looked ok at 150k, and everybody was pissed about the belt being a maintanance item at 150k. Calculated risk

 

[DarkHorseRacing]

Yea, probably because the belt looked ok at 150k, and everybody was pissed about the belt being a maintanance item at 150k. Calculated risk

I still think whether it’s 150k or 200k most vehicle owners are really going to have to do it only once. Most people don’t keep vehicles that long.

Now second owners might have to do the second one but they should know what they are buying, and I can’t imagine there won’t be other crap that breaks and kills the vehicle first.

 

[EmpirE231]

Haven’t watched the video yet, but the 200k interval on the belt isn’t that big of a deal anymore. Most likely by 200k, it’s about time to go through the trans anyway.

 

[Bigbore500r]

I still think whether it’s 150k or 200k most vehicle owners are really going to have to do it only once. Most people don’t keep vehicles that long.

Now second owners might have to do the second one but they should know what they are buying, and I can’t imagine there won’t be other crap that breaks and kills the vehicle first.

Once it hits 150k that baby is for sale to it's 4th owner at a random used car lot......
"Of course the belt was changed sir"

 

[Xring01]

What makes diesel engines last is gear train. Chains and belts both build maintenance intervals.

Down side is its noisy and I am sure what GM was trying to avoid. Dropping a trans? I agree that's a bit much and a maintenance item like this should have been in the front.

Dude did you even see the tear down video…
If you did, right behind the “oil belt”, is several chains for the timing systems. SEVERAL…

If your statement is accurate, then why use chains for the timing system, versus belts? Especially in the exact same area of the engine?????

 

[Xring01]

Haven’t watched the video yet, but the 200k interval on the belt isn’t that big of a deal anymore. Most likely by 200k, it’s about time to go through the trans anyway.

Damn, you guys have low expectations for very expensive Diesel Trucks.

My 2002 GMC 2500 6.6 DMax 4x4, was sold with 245000 miles pretty much bone stock. I think I replaced one ball joint, an o ring in the diesel primer bulb…. That truck got me from point A to B every time…

Thats was a 2002 truck that cost a hell of alot less than todays trucks.
Where am I headed…

If a truck is gonna cost me the price of todays trucks, then that damn thing better have a very long life expectancy and very low maintenance. Because if it doesn’t why would I pay such a premium for something that is worse than its predecessors? Might as well by a used one (thats more reliable and better return on investment) and fix it up…

Seriously think about what your saying.
If a Chevy 5.3 truck is $55K with an expected life of 250,000 miles… (if you doubt my expections, look my my old posts, when/before I purchased my 2021 Chevy 5.3 truck 2 years ago)…

and a Chevy 3.0 DM is $65K (OR MORE) for the exact same trim level… and an expected life of 150,000miles before a major repair/expense, or best case 200,000miles. Tows the same load as 5.3…..

Why in the hell would you pay the premium for 3.0 DM????? You not going to make the initial price difference over better fuel economy but added costs of DEF fluid. The 3.0 is going to take a huge depreciation hit 150,000 miles…

 

[LakeMead Boater]

Damn, you guys have low expectations for very expensive Diesel Trucks.

My 2002 GMC 2500 6.6 DMax 4x4, was sold with 245000 miles pretty much bone stock. I think I replaced one ball joint, an o ring in the diesel primer bulb…. That truck got me from point A to B every time…

Thats was a 2002 truck that cost a hell of alot less than todays trucks.
Where am I headed…

If a truck is gonna cost me the price of todays trucks, then that damn thing better have a very long life expectancy and very low maintenance. Because if it doesn’t why would I pay such a premium for something that is worse than its predecessors? Might as well by a used one (thats more reliable and better return on investment) and fix it up…

Seriously think about what your saying.
If a Chevy 5.3 truck is $55K with an expected life of 250,000 miles… (if you doubt my expections, look my my old posts, when/before I purchased my 2021 Chevy 5.3 truck 2 years ago)…

and a Chevy 3.0 DM is $65K (OR MORE) for the exact same trim level… and an expected life of 150,000miles before a major repair/expense, or best case 200,000miles. Tows the same load as 5.3…..

Why in the hell would you pay the premium for 3.0 DM????? You not going to make the initial price difference over better fuel economy but added costs of DEF fluid. The 3.0 is going to take a huge depreciation hit 150,000 miles…

It’s surprising, but the price difference between the 5.3 and 3.0 is under $2000.

 

[HALLETT BOY]

He reminds me of a younger Adam Sandler , looks and sounds like him .

 

[Sleek-Jet]

I'm guessing GM runs a belt for vibration dampening instead of a chain. But I agree questioning the logic of using a belt in the first place and not running a gear.

 

[OCMerrill]

Dude did you even see the tear down video…
If you did, right behind the “oil belt”, is several chains for the timing systems. SEVERAL…

If your statement is accurate, then why use chains for the timing system, versus belts?

Chains don't go the distance like a gear train. They stretch and eventually need to be serviced.
Perhaps you have never owned and ridden a dirt bike. When I raced desert it was chain and sprockets every third race.

Maybe your not aware but all Duramax 6.6, 6.7 Ford, and Cummins use gears to run the timing including the cam and injection pump and oil pump. Eric has those videos to watch also.

Here is my 5.9 in an 04 truck. No belts...no chains. Noisy as shit. That was my point. This is a 280k+ mile gear train. No wear what so ever. Removed cover to sleeve crank and replace the crank seal and a ton of other maintenance.

 

[4Waters]

I'm guessing GM runs a belt for vibration dampening instead of a chain. But I agree questioning the logic of using a belt in the first place and not running a gear.

A gear may cause a whine

 

[Xring01]

Chains don't go the distance like a gear train. They stretch and eventually need to be serviced.
Perhaps you have never owned and ridden a dirt bike. When I raced desert it was chain and sprockets every third race.

Maybe your not aware but all Duramax 6.6, 6.7 Ford, and Cummins use gears to run the timing including the cam and injection pump and oil pump. Eric has those videos to watch also.

Here is my 5.9 in an 04 truck. No belts...no chains. Noisy as shit. That was my point. This is a 280k+ mile gear train. No wear what so ever. Removed cover to sleeve crank and replace the crank seal and a ton of other maintenance.

View attachment 1302506

DUDE…
COME ON MAN…

Look at the video that I posted above…

The picture your showing is not the DM 3.0…

The DM 3.0 Oil belt is in the rear of the engine behind the fly wheel, and behind that is the time system/chains…

If a chain is good enough for the time system of a DM3.0… and the oil system is right in front of the timing system.. Why use a belt??? Both systems are literally stacked next to one another at the rear of the system. You literally have to remove the oil belt to get to the time system/chain.

Your statements make no sense when you truly look at exactly what I am referring to, please look at the video I posted above…

 

[Xring01]

It’s surprising, but the price difference between the 5.3 and 3.0 is under $2000.

That changed since 2021…when I bought my mine.

maybe because they where not selling the volume they thought. Thats a guess on my part

 

[Taboma]

I'm guessing GM runs a belt for vibration dampening instead of a chain. But I agree questioning the logic of using a belt in the first place and not running a gear.

According to a Pickup Talk Youtube discussion with a GMC rep, the decision was essentially due to packaging restraints with regard to a chain of the required length requiring a tensioner adding to engine length.
Also, that loss of this belt is not immediately catastrophic such as breaking an interference timing belt, as it provides adequate warning allowing time to pull over.

 

[Xring01]

According to a Pickup Talk Youtube discussion with a GMC rep, the decision was essentially due to packaging restraints with regard to a chain of the required length requiring a tensioner adding to engine length.
Also, that loss of this belt is not immediately catastrophic such as breaking an interference timing belt, as it provides adequate warning allowing time to pull over.

So they acknowledge a chain was the better option, and chose a work around…

The last sentence/comment makes no sense. Regardless of a chain/belt a failure should react the same way with “adequate warning” if the systems are built to the same standards. The bigger question to me is which one is more reliable and less likely to fail.

 

[timstoy]

Once it hits 150k that baby is for sale to it's 4th owner at a random used car lot......
"Or course the belt was changed sir"

And a Krylon engine rebuild!

 

[Taboma]

So they acknowledge a chain was the better option, and chose a work around…

The last sentence/comment makes no sense. Regardless of a chain/belt a failure should react the same way with “adequate warning” if the systems are built to the same standards. The bigger question to me is which one is more reliable and less likely to fail.

Yup, they acknowledged that the belt is good enough and if you don't like it, move on. By the way, when you find an automotive manufacturer who doesn't make compromises based on marketing, price, packaging, and something being good enough, please post it up.

 

[pkrrvr619]

Do you use this to pull your Magic, and if so how does it do? We have a Mach 26 and interested in the 3.0DM for the little amount we tow it and the possibility if we wanted to do longer trips towing the boat, or towing across the desert to bring the boat home from the river if needed.

We tow our 25 daytona behind the yukon with the 3.0 and it works great.

 

[NeedlesRat]

We tow our 25 daytona behind the yukon with the 3.0 and it works great.

Thanks. My biggest issue with my current Silverado with the 5.3 isn’t the towing with it, it’s getting it out of any ramps that are shit since it’s 2WD, it spins the tires a bit and I don’t want to end up on YouTube as “that guy” at the ramp lol. Since the last boat was a Stoker, never even thought about it but now I want something better suited for the boat. It never goes more than a few miles from storage to the ramp, but I want the flexibility to tow it comfortably across the desert or on long trips if we decided to do something different.

 

[Xring01]

Yup, they acknowledged that the belt is good enough and if you don't like it, move on. By the way, when you find an automotive manufacturer who doesn't make compromises based on marketing, price, packaging, and something being good enough, please post it up.

Agreed, but I was holding GM to a higher standard than their competition…

 

[Xring01]

Thanks. My biggest issue with my current Silverado with the 5.3 isn’t the towing with it, it’s getting it out of any ramps that are shit since it’s 2WD, it spins the tires a bit and I don’t want to end up on YouTube as “that guy” at the ramp lol. Since the last boat was a Stoker, never even thought about it but now I want something better suited for the boat. It never goes more than a few miles from storage to the ramp, but I want the flexibility to tow it comfortably across the desert or on long trips if we decided to do something different.

I launched and retrieved my deckboat many many many times with my 5.3. 2021 Chevy on many many different launch ramps.
Never used 4x4 once… Towing weight was less than 5000lbs I am guessing.

Those must be some shitty launch ramps.

 

[Justsomeguy]

Damn, you guys have low expectations for very expensive Diesel Trucks.

My 2002 GMC 2500 6.6 DMax 4x4, was sold with 245000 miles pretty much bone stock. I think I replaced one ball joint, an o ring in the diesel primer bulb…. That truck got me from point A to B every time…

Thats was a 2002 truck that cost a hell of alot less than todays trucks.
Where am I headed…

If a truck is gonna cost me the price of todays trucks, then that damn thing better have a very long life expectancy and very low maintenance. Because if it doesn’t why would I pay such a premium for something that is worse than its predecessors? Might as well by a used one (thats more reliable and better return on investment) and fix it up…

Seriously think about what your saying.
If a Chevy 5.3 truck is $55K with an expected life of 250,000 miles… (if you doubt my expections, look my my old posts, when/before I purchased my 2021 Chevy 5.3 truck 2 years ago)…

and a Chevy 3.0 DM is $65K (OR MORE) for the exact same trim level… and an expected life of 150,000miles before a major repair/expense, or best case 200,000miles. Tows the same load as 5.3…..

Why in the hell would you pay the premium for 3.0 DM????? You not going to make the initial price difference over better fuel economy but added costs of DEF fluid. The 3.0 is going to take a huge depreciation hit 150,000 miles…

That was a good truck. I've had a few little things on mine. But my biggest complaint is the front end. How you only replaced one ball joint blows my mind. I have a had a few front wnd issues. But im kinda weird about noise or feelings that seem off to me. Maybe some are in my head. Maybe its because i cant leave anything stock. Wno knows. I get it was stock. But still. It's a lot of weight on ifs. Other than that. Pulley and belt in Pismo a few wewks ago and a rubber fuel hose split. The other trouble makers, well that off roading incident.

With the price and problems of modern day systems. I'm not sure I'll get rid of mine. So cal diesel block and Inglewood transmission should send this thing into a nice lifespan after this factory power train gives out. Full kryptonite front end now. So any replacements are easy.

 

[pkrrvr619]

Thanks. My biggest issue with my current Silverado with the 5.3 isn’t the towing with it, it’s getting it out of any ramps that are shit since it’s 2WD, it spins the tires a bit and I don’t want to end up on YouTube as “that guy” at the ramp lol. Since the last boat was a Stoker, never even thought about it but now I want something better suited for the boat. It never goes more than a few miles from storage to the ramp, but I want the flexibility to tow it comfortably across the desert or on long trips if we decided to do something different.

Yep my 2500 duramax spins the tires as well at some ramps. hop on the hitch and it solves the spin however the smaller yukon with 4x performs flawlessly.

 

[Taboma]

Agreed, but I was holding GM to a higher standard than their competition…

Well when Chrysler/Ram introduced the 3.0 Ecodiesel, between two neighbors they went through three of them before 5,000 miles.
New HD Ram diesels owned by members are suffering catastrophic transmission failures shortly after purchase.

One of those was holding out to purchase a new Yukon Denali with the LZO, after reading of it's improvements over the LM2, this belt wasn't a negative for him, but then like me, he's old and likely he'll suffer a physical failure before the truck does.
When he discovered that GMC for whatever reason had chosen to continue the LM2 in the Yukons, unlike their trucks, he bailed and bought a Lexus Hybrid as fuel economy was his prime motivation.

I'm still disappointed in Ford's putting form over function with their decision to place the front license plate bracket in front of the Turbo intercooler. That according to my Ford R&D Engineer neighbor was 100% based on marketing feedback and went with that in spite of the engineers concerns.
Ford's brilliant marketing remedy was to issue a supplement advising to remove the plate when off-roading.

Good luck sorting out the market to find a vehicle that has the features you desire and hasn't compromised in to many other areas.

 

[EmpirE231]

Damn, you guys have low expectations for very expensive Diesel Trucks.

My 2002 GMC 2500 6.6 DMax 4x4, was sold with 245000 miles pretty much bone stock. I think I replaced one ball joint, an o ring in the diesel primer bulb…. That truck got me from point A to B every time…

Thats was a 2002 truck that cost a hell of alot less than todays trucks.
Where am I headed…

If a truck is gonna cost me the price of todays trucks, then that damn thing better have a very long life expectancy and very low maintenance. Because if it doesn’t why would I pay such a premium for something that is worse than its predecessors? Might as well by a used one (thats more reliable and better return on investment) and fix it up…

Seriously think about what your saying.
If a Chevy 5.3 truck is $55K with an expected life of 250,000 miles… (if you doubt my expections, look my my old posts, when/before I purchased my 2021 Chevy 5.3 truck 2 years ago)…

and a Chevy 3.0 DM is $65K (OR MORE) for the exact same trim level… and an expected life of 150,000miles before a major repair/expense, or best case 200,000miles. Tows the same load as 5.3…..

Why in the hell would you pay the premium for 3.0 DM????? You not going to make the initial price difference over better fuel economy but added costs of DEF fluid. The 3.0 is going to take a huge depreciation hit 150,000 miles…

My 05 1500 w/ a 5.3 needed a trans at 175k. Then lifters went out @ 200k.

 

[Xring01]

Well when Chrysler/Ram introduced the 3.0 Ecodiesel, between two neighbors they went through three of them before 5,000 miles.
New HD Ram diesels owned by members are suffering catastrophic transmission failures shortly after purchase.

One of those was holding out to purchase a new Yukon Denali with the LZO, after reading of it's improvements over the LM2, this belt wasn't a negative for him, but then like me, he's old and likely he'll suffer a physical failure before the truck does.
When he discovered that GMC for whatever reason had chosen to continue the LM2 in the Yukons, unlike their trucks, he bailed and bought a Lexus Hybrid as fuel economy was his prime motivation.

I'm still disappointed in Ford's putting form over function with their decision to place the front license plate bracket in front of the Turbo intercooler. That according to my Ford R&D Engineer neighbor was 100% based on marketing feedback and went with that in spite of the engineers concerns.
Ford's brilliant marketing remedy was to issue a supplement advising to remove the plate when off-roading.

Good luck sorting out the market to find a vehicle that has the features you desire and hasn't compromised in to many other areas.

As far as I am concerned… I did…
Highly modified 2016 GMC 6.6 DM, 4x4. Bought it used, highly modified by a Mechanical Engineer who purpose built it to his standards. Lets just say all the typical things that fail on these trucks has been removed, and everything else has been upgraded.

Its a beast that loves towing.

I hope to keep it till I die. Unless it gets totaled or completely worn out… Then its going to be my old man truck when I get there. But I am only 52 years old. Time will tell.

 

[Bigbore500r]

Im just here to remind the blue oval folks that the Ford 5.0 and 2.7 Ecoboost have an oil pump belt, located in the worst spot possible - behind 2 rows of DOHC timing chains and tensioner assemblies, which are behind the front timing chain cover, which is behind all of the engines accessories and water pump ........

 

[JFMFG]

Yea, probably because the belt looked ok at 150k, and everybody was pissed about the belt being a maintanance item at 150k. Calculated risk

Speaking of calculated risk is Eric still in Mexico lol.