Maggie’s 6.6 duramax... good or bad?

[stello1001]

Like the title states, were these engines very problematic? I have no experience with diesel engines so hoping someone could be helpful.

Not too long ago, I got a Ford 6.0 and mostly everyone said they were not reliable unless bullet proof. Turned it around real quick for a profit.

From what I gathered, the "bulletproofing" process is Some thing that applied to those ford engines specifically and not all diesel engines. Having said that, can I expect to have piece of mind if I am to purchase this truck?

Thanks,

S


ETA:

The one I'm looking at is a 2004 with 210,XXX miles. Owner said he recently replaced injectors which is a very costly upgrade I dont have to worry about.

 

[silentwoods]

I own an 06 that we bought the end of 05.
It was a transition model I guess. Tbz with LLY coding.
Still have it, 140k, original injectors Allison 1000 series tranny, nothing but oil changes and drive it.
Been a hell of a truck overall, can't speak of the Late models. But mine is a simpler version than current models.

 

[Willoughby1971]

I’ve had three trucks with the Duramax (2007, 2012 & 2018)and they have all been trouble free.

 

[BigTex]

Its a solid motor, the Duramax has been a 6.6l the entire time with slight changes every few years. That said, there's more to a truck than the motor. What year model is the one you are looking at?

 

[stello1001]

I guess I should have mentioned that lol. I thought the 6.6 duramax trucks were only from a certain period but I guess not.

The one I'm looking at is 2004 with 210,XXX miles. Owner said he recently replaced injectors which is a very costly upgrade I dont have to worry about. It is also in very good condition. I know this guy and I know how he takes care of his stuff. I'm pretty sure it'll be hard to find another one as well taken care of as this one.

I test drove it and everything ran really freaking smooth. My biggest thing right now is the fact that I'll be going from an 04 crew cab, half ton, to a much bigger truck. I'm also looking at a crew cab but boy is that thing so much bigger. I guess it's a concern because it would also be my daily driver and I'm not too sure how I feel going everywhere with so much truck if that makes sense. Parking, backing up, driving, etc is not a problem and not something I'm concerned. Just rather the me going anywhere and everywhere with what will feel like a monster truck to me lol.

But I'm really glad to know that these trucks don't have a bad history like those ford diesel engines.

 

[safarigene]

I have a 2006 2500HD that I bought with 247K on it. Now has 259k and is still running strong. Only thing I have had to do is replace the fuel filter. Have towed a toy hauler several hundred miles with no issues. I have had two Ford 7.3s and one 6.0. One 7.3 had a Banks Powerpack on it and this Duramax flat out smokes it.

 

[benchmstr]

First off, all duramax 2500 and 3500 are 6.6...

and duramax is the best diesel there is!

I own 2 ford diesels now, but I’m always in the market for a good used duramax.

lbz, lmm, and lml are the way to go.

I personally would not get an 04...but it’s more personal preference than anything.

bench

 

[benchmstr]

I guess I should have mentioned that lol. I thought the 6.6 duramax trucks were only from a certain period but I guess not.

The one I'm looking at is 2004 with 210,XXX miles. Owner said he recently replaced injectors which is a very costly upgrade I dont have to worry about. It is also in very good condition. I know this guy and I know how he takes care of his stuff. I'm pretty sure it'll be hard to find another one as well taken care of as this one.

I test drove it and everything ran really freaking smooth. My biggest thing right now is the fact that I'll be going from an 04 crew cab, half ton, to a much bigger truck. I'm also looking at a crew cab but boy is that thing so much bigger. I guess it's a concern because it would also be my daily driver and I'm not too sure how I feel going everywhere with so much truck if that makes sense. Parking, backing up, driving, etc is not a problem and not something I'm concerned. Just rather the me going anywhere and everywhere with what will feel like a monster truck to me lol.

But I'm really glad to know that these trucks don't have a bad history like those ford diesel engines.

You have to understand, all diesels have a problem like bulletproofing.

the duramax of the year model you are looking at has cooling/ injector issues that cost as much as bulletproofing.

and every duramax after that has a good cooling system...but the fuel system is still very expensive if it shits the bed. Especially the lml(2011-2016) these had a cp4 fuel pump on them and no factory lift pump...when that cp4 died it was an automatic $10k bill because it took most of the engine with it!

I am saying now what I said in your original thread....this is the diesel game,everything is expensive and everything has its problems!

you won’t be in the diesel game without a lot of headaches.

I remember you being in Texas. If you choose to keep the 6.0 I can hook you up with my mechanic..I’ve used a lot but he’s the most honest and knowledgeable I have ever came across when it comes to ford diesels.

just had an oil leak issue on my built excursion and my lowest quote was $5k...he got it done for $850...he’s an honest man

bench

 

[benchmstr]

I have a 2006 2500HD that I bought with 247K on it. Now has 259k and is still running strong. Only thing I have had to do is replace the fuel filter. Have towed a toy hauler several hundred miles with no issues. I have had two Ford 7.3s and one 6.0. One 7.3 had a Banks Powerpack on it and this Duramax flat out smokes it.

Everything smokes a 7.3 lol

every one talks about 7.3 reliability, but no one talks about how they don’t make enough power, or rev high enough to hurt themselves.

basically if you have a modern 1500 series truck with a gasoline v6, you have significantly more power than that overhyped oil leak of a7.3

bench

 

[silentwoods]

Everything smokes a 7.3 lol

every one talks about 7.3 reliability, but no one talks about how they don’t make enough power, or rev high enough to hurt themselves.

basically if you have a modern 1500 series truck with a gasoline v6, you have significantly more power than that overhyped oil leak of a7.3

bench

Agree. Completely overrated.

 

[FishinGuns]

You have to understand, all diesels have a problem like bulletproofing.

the duramax of the year model you are looking at has cooling/ injector issues that cost as much as bulletproofing.

and every duramax after that has a good cooling system...but the fuel system is still very expensive if it shits the bed. Especially the lml(2011-2016) these had a cp4 fuel pump on them and no factory lift pump...when that cp4 died it was an automatic $10k bill because it took most of the engine with it!

I am saying now what I said in your original thread....this is the diesel game,everything is expensive and everything has its problems!

you won’t be in the diesel game without a lot of headaches.

I remember you being in Texas. If you choose to keep the 6.0 I can hook you up with my mechanic..I’ve used a lot but he’s the most honest and knowledgeable I have ever came across when it comes to ford diesels.

just had an oil leak issue on my built excursion and my lowest quote was $5k...he got it done for $850...he’s an honest man

bench

This is what I’ve come to understand about diesel. I don’t haul enough to ever justify the headache and costs. My next truck will be a 3/4 ton gasser coming from a current 1/2 ton. I’ll regear it if I want more pep.

 

[DukeGSP]

the 6.6 in the earlier models are solid. not any emissions on them to have to worry about. anything 15 and newer and it's pricey to delete. I'm a ford guy myself but the 6.6 is proven. I too once owned a 6.blow, I couldn't get rid of it fast enough. good luck with the new to you truck.

 

[benchmstr]

the 6.6 in the earlier models are solid. not any emissions on them to have to worry about. anything 15 and newer and it's pricey to delete. I'm a ford guy myself but the 6.6 is proven. I too once owned a 6.blow, I couldn't get rid of it fast enough. good luck with the new to you truck.

The 6.0 isn’t bad once you figure it out!

my excursion had half a million miles on it before I rewarded it with a built kill devil long block...it didn’t need a new engine, I just got it.


A lot of them were problematic, but a lot more were over-tuned, and under maintained.

 

[DukeGSP]

The 6.0 isn’t bad once you figure it out!

my excursion had half a million miles on it before I rewarded it with a built kill devil long block...it didn’t need a new engine, I just got it.


A lot of them were problematic, but a lot more were over-tuned, and under maintained.

maybe so. but I don't think I should have to pay 50k for a truck to turn around and spend thousands more to keep it on the road. the 6.0 I had, had roughly 9-10K under the hood and it still went to the shop every other month. it put a bad taste in my mouth.

I owned two 6.4's that was also the bastard child of ford and I loved the hell out of them. both were deleted and made stupid power. I owned a 15 6.7 and also deleted it and it was probably my best engine to date. seems like ford is going to stick with this 6.7.

also owned a 7.3. it was a tank, it didn't go anywhere fast but it was a workhorse.

 

[benchmstr]

maybe so. but I don't think I should have to pay 50k for a truck to turn around and spend thousands more to keep it on the road. the 6.0 I had, had roughly 9-10K under the hood and it still went to the shop every other month. it put a bad taste in my mouth.

I owned two 6.4's that was also the bastard child of ford and I loved the hell out of them. both were deleted and made stupid power. I owned a 15 6.7 and also deleted it and it was probably my best engine to date. seems like ford is going to stick with this 6.7.

also owned a 7.3. it was a tank, it didn't go anywhere fast but it was a workhorse.

My wife's brand new king ranch 6.7 powerstroke didn't make it to it's first oil change! Lol

Going down 59 aat around 67mph with the cruise control set....dropped a valve and took the engine and transmission.

Ford had to do a metallurgy report on it....4 different valve keepers were poor quality metal..I had the option of a replacement truck or refund us what we had paid so far.

We opted for the money back...when that check comes in my wife is dead set on a new Duramax.

Bench

 

[Terry Cross]

Put 220K on a 2015 GMC 2500 HD with DuraMax and 6 speed Allison. Trouble free and a beast. Driving a 2020 GMC 2500 HD with 10 speed Allison since Feb. So far even more impressive. That transmission is giving me 18 to 20 MPG in city and mixed driving. I could care less about re-programming , etc because they accelerate like a race car, pull like a tractor and get great mileage as is.

Daily driver plus pulling trailer and fully loaded when doing classes. I believe Isuzu used to make that engine for GM. GM maybe making it under license now but they have that super high compression engine figured out.


./

 

[rlsmith1]

I had an 08 Duramax (LMM) for a year and loved it. Duramax's are great. As others have said, the LLY's (2004-2006) were known for their injector failures at 180k or so. The LBZ (2006-2007) and LMM (2008-2010) are very similar engines and are generally very reliable. A good lift pump with a water separator (FASS, etc.) really helps all the older Duramax's keep their injectors alive. duramaxforum is a great site with tons of info too.

If your truck is tuned / deleted, you need to be careful with the tranny. Anything more than +80hp is going to take away form the transmission reliability if you run it hard / tow with it. I ran my LMM on +150hp and it ran perfectly for me.

It's a good thing I sold that truck or I would have put 60% over injectors, compound turbos, and built the tranny to run 700+ rwhp and crazy torque. They are a blast to make go fast!

 

[wh20crazy]

04, or 04.5? They changed the engine from the lb7 to the lly mid- year. Lb7's fill the crankcase with fuel when the injectors leak. The design changed that for the lly. Lb7 had no emissions equipment. Lly has egr, PCV and cat. Head gaskets were hit or miss with the lly (fixed with the lbz). If the lly is tuned and HG's are original, they'll probably go. Stock lly tune won't make over 20lbs. Of boost. My 90 hp tune makes a bit more. Most shops are $4 to 5 grand to do the head gaskets and studs (it's a big job).

If it's tuned and has the stock trans, go easy on the 4 to 5 shift.

I have an 05 that my dad bought new. I added 5 efi live tunes (90hp max). Then I blew a head gasket. That's been the only problem I've had. 6,800lbs, 5.7 seconds 0 to 60 and 22mpg. Everything about a diesel is more expensive. I don't pull anything, but it'll be a long time before I go back to a gas burner.

 

[mtrmn]

If you don't pull loads day in/day out or maybe have a large travel trailer or stock trailer I'd say stick with a gas burner. These modern diesels are extremely expensive when you buy them and they never stop sucking up all your money. I have a Chevrolet HD with a 6.0L gasser that has pulled everything I've tied behind it without a problem, and I can replace the engine (and maybe transmission too) for what it costs to put an injector pump on a diesel. The latest model Fords (don't know about others) require complete removal of the cab for just about any engine work. I'm a mechanic by trade and this lack of any common sense whatsoever (tilt cab anyone?) makes me want to throw up. JMHO and YMMV

 

[isofahunter]

BIL has an 04 with 300k on it, most of those with a trailer behind it. Injectors were done 225Kish and it has been trouble free.

 

[candyx]

2018 its a rocket off the line only got 15,000 miles on the stock tires before they were slicks. Then I had to use four wheel drive in the rain just to take off at a light.

 

[BigTex]

My '15 is great. I plan on driving it another 10 years.

 

[AKMarty]

I guess I should have mentioned that lol. I thought the 6.6 duramax trucks were only from a certain period but I guess not.

The one I'm looking at is 2004 with 210,XXX miles. Owner said he recently replaced injectors which is a very costly upgrade I dont have to worry about. It is also in very good condition. I know this guy and I know how he takes care of his stuff. I'm pretty sure it'll be hard to find another one as well taken care of as this one.

I test drove it and everything ran really freaking smooth. My biggest thing right now is the fact that I'll be going from an 04 crew cab, half ton, to a much bigger truck. I'm also looking at a crew cab but boy is that thing so much bigger. I guess it's a concern because it would also be my daily driver and I'm not too sure how I feel going everywhere with so much truck if that makes sense. Parking, backing up, driving, etc is not a problem and not something I'm concerned. Just rather the me going anywhere and everywhere with what will feel like a monster truck to me lol.

But I'm really glad to know that these trucks don't have a bad history like those ford diesel engines.

Mine is an 07 (LBZ) 2500HD. It’s my daily driver. Parking & driving not a big issue. I’ve replaced a couple half-shafts over the years due to boots splitting. Easy fix. I’m due to replace the shackles on the rear springs. I did just replace all 8 injectors. Glad they lived this long after she was fed gasoline by accident. Still don’t know who.

I like the Duramax/Allison combo. Don’t like the Chevy wiring in the cab. Lots of backlights have gone out in the dash as well as a broken wire in the gearshift tow/haul switch.

All stock, 204,000mi.

 

[1moaoff]

I own a few from each manufacturer. Duramax and allison combination is good but they still have quirks like any other. If you are not hauling more than 40% of the time buy a gas motor. Just a top end rebuild comes closish to a long block in gas motor, plus everything else is more expensive.

 

[benchmstr]

If I had to get a new truck today to replace my excursion(sad day). It would likely be a newer lml duramax.

I would immediately delete it completely, swap the fuel pump to a cp3 from the cp4, throw on a light tune and lift pump and drive it forever in complete confidence.

bench

 

[BigTex]

If I had to get a new truck today to replace my excursion(sad day). It would likely be a newer lml duramax.

I would immediately delete it completely, swap the fuel pump to a cp3 from the cp4, throw on a light tune and lift pump and drive it forever in complete confidence.

bench

That is exactly what I have. Its been great!

 

[stello1001]

Thank you all for the responses. The truck is fucking badass and I like it. Again, it's an 04 and with 210,XXX miles, it's really well taken care of. It has a bully dog (I believe that's the name of the brand) programmer as well as new injectors. I definitely like it.

However, after much thinking, I'm not sure I'll buy it. I have a pretty large travel trailer but I rarely move it. It might get moved about 3 to 4 times per year. This year, it has not been moved. While not ideal, my half ton truck has been the one to get it done in the past. I'm not entirely sure I can justify buying that truck for how much I'll actually need the extra power over my current 5.3 gas engine truck.

Thanks all for helping...

 

[jphil108]

My 7.3 has been good but they are definitely underpowered for their displacement, that lower brake mean effective pressure of the old international is part of why they run so long, they just can’t push themselves hard enough to break that much. Absolutely the worst water separator drain valve ever out in. A diesel. the Chevy trucks I’ve driven have all been pretty good and have run the gamut of engines and fuels, 2000 with a 454 ( I think) 05 with a 6 liter, and an 07 with a duramax. I loved that 2000 model it’s was comfortable as hell and did great pulling but the duramax was a solid and responsive engine and puts my 7.3 to shame (it should, it’s 8 years and a generation newer). We clogged the diesel particulate filter on the duramax by idling in the cold watching a team member test winter tires at concord speedway, but the delete stuff can take care of most of that kind of problem. I also remember oil changes being a pain in the ass but you’re going to have trouble like that with any bigger truck. I hate to say it but the Cummins have the least number of parts to fail and everything is in a straight line so they’re pretty easy to work on in comparison and it only has half as many head gaskets to fail. Sometimes you can find Frankenstein trucks with a Cummins engine, Allison transmission, and a ford chassis, if they get the electrical right those are pretty good vehicles. What was mentioned above about getting a gas engine if you don’t tow much is sound advice, maintenance is a lot cheaper, and the Chevy 6.0 is about as proven as a design can be. Even a replacement long block is pretty cheap when you wear out the original.

I wouldn’t worry about the size of the truck, you’ll get used to it really quick, plus Chevy has pretty tight steering radius in most of their trucks. My ford needs a turning basin like a super max tanker to do a u-turn. I went from a mustang to a crew cab dually in college and it wasn’t a problem, the first time you realize you can just drop a 4*8’ sheet down in the bed or move half your stuff in one truck load, you’ll quit caring about how hard it is to park and then you’ll figure out you can park anything. you can also usually just park a little further away and walk, keeps you healthy and out of the morbidly obese rat race to nab the first spot closest to the door.

 

[benchmstr]

That is exactly what I have. Its been great!

People are scared shitless of the cp4 on the duramax...but the 6.7 powerstroke has the same pump! The only difference is the Ford has a factory lift pump.

Im really not concerned about the cp4 shitting the bed with a lift pump..I’ve owned 3 6.7 powerstrokes and Never had an issue....I just don’t see why why GM didn’t install a factory lift pump! They usually have their shit together but dropped a $10,000 ball on that one.

bench

 

[BigTex]

People are scared shitless of the cp4 on the duramax...but the 6.7 powerstroke has the same pump! The only difference is the Ford has a factory lift pump.

Im really not concerned about the cp4 shitting the bed with a lift pump..I’ve owned 3 6.7 powerstrokes and Never had an issue....I just don’t see why why GM didn’t install a factory lift pump! They usually have their shit together but dropped a $10,000 ball on that one.

bench

I agree, I went ahead and did a CP3 conversion when I had everything else done, didn't cost much more since they were already in there. That with the 165gph Air Dog 4g and I'm all set.

 

[Lazlo]

I agree, I went ahead and did a CP3 conversion when I had everything else done, didn't cost much more since they were already in there. That with the 165gph Air Dog 4g and I'm all set.

CP4 victim here. Not a fun experience.

Either a lift pump or fuel additive will help with the CP4 grenading, as the issue apparently stems from the US conversion to ULS diesel and lowering the lubricity content. Use an additive that increases fuel lubricity by replacing what was lost in the sulphur reducing process, and you should be ok.

 

[benchmstr]

CP4 victim here. Not a fun experience.

Either a lift pump or fuel additive will help with the CP4 grenading, as the issue apparently stems from the US conversion to ULS diesel and lowering the lubricity content. Use an additive that increases fuel lubricity by replacing what was lost in the sulphur reducing process, and you should be ok.

I use archoil on every fill up in every diesel vehicle I own....its not a luxury, its a necessity with a modern diesel.

when I forget to order a new bottle, I will use the hot shot secret EDT because I can get in locally....but its just until the archoil comes in.

bench