So I am new to the duramax world. I am getting ready to buy a 2004.5 LLY that's bone stock except new Michelins with only 12,000 original miles. Always garaged. I plan on towing my travel trailer as well as various trailers (Some fairly heavy and some not) for my business. Are there any mods that I should be considering that might prevent head gasket failure in the future? My second wish or preference is to improve MPG. I don't plan on adding insane amounts of HP or using my truck as a hot rod however I push snow in the winter which tends to block airflow through the stack. Maybe I will just use my 6.0 gas for pushing snow. What's your suggestions/ideas? Thanks.
LLY: I'm new to duramax and need suggestions
- Thread starter Gmclly
- Start date
Ensure it’s all in working order first. If it truly has that little miles then you’re gonna run into dry rot like the other guy said most likely. After that, exhaust, lbz mouthpiece, a good lift pump, and EFILive will give you a nice boost. Then save for a built transmission
I’d do a upgraded mouthpiece, egr blocker and a good exhaust and work it like you’re intending. Only hoses I’d worry about is the fuel lines off the cp3 and fuel filter housing, mine sat 6 years in a heated shop and everything was as good as new at 10k miles.
Yes, 12,000 miles. It gets exercised every couple weeks for the last 10 years as well as regular maintenance. It belonged to a relative who has meticulously cared for all of his vehicles for as long as I've known him. Belts, hoses, and etc were replaced in the last 5 years or so. New set of Michelins 6 months ago.
I have to ask. What you pick it up for? That’s a brand new truck thats going to just get used as a work truck..... crazy but congrats! I love my lilly great truck youll love it
I don't want to say exactly but I can tell you that it's under $20k. It won't necessarily be used as a work truck might be, I have a 2008 6.0 gas that's dedicated as a work truck. This lly will be my nicer one with leather and all the bells and whistles. It's spent it's life in the southwest and has never seen snow and salty roads. I do however want to us the lly to pull my camper and it will pull some of my trailers for my business from time to time. I'm undecided if I want to push snow with it since the plow greatly reduces airflow to the cooling system.
I wouldn't plow with it just since it will destroy the truck. Plow trucks usually don't last long or are all rotted out
s&b or lbz turbo mouthpiece and trans cooler
I had some overheating pulling a dump trailer with a 239d cat
this fixed it.
My engine still gets i little warm with weight in the rear with a plow on tho
mines also the 04.5
I had some overheating pulling a dump trailer with a 239d cat
this fixed it.
My engine still gets i little warm with weight in the rear with a plow on tho
mines also the 04.5
12k? Nice. The LLY I just bought has 405K on it:rofl: Well 405 on the body and axles everything else is new
I own 2 LLY with the 03 LB7 being converted to LLY. Heres my list in order of importance.
1. ice pick all 8 injector plugs, reroute injector wires 2 and 7 so they have some slack and aren't pulled tight against plugs on top of the injector.
2. Cut the zip tie holding the wiring harness to the FICM mounting bracket (silver box right front of the engine, under the air intake pipe), pull it back and make sure there is no bare wire showing from rubbing on the bracket, use a hose guard on the harness and zip tie it back down to the bracket.
3. LBZ or S&B mouth piece, huge problem with the LLY. Many threads on the Pros of this.
4. EGR delete or blocker plate. PCV reroute. These should be done together as the PCV oil and EGR soot really gum up the intake clams and heads.
5. 50-75 hp tune and a boost Pyro gauge, efi live, diablo sport, h&s whatever. Just leave it on one tune, switching tunes all the time just angers the transmission (it's a learning trans, based on HP and driving habits)
6. Shim the Fuel Rail relief valve, or install a race valve.
7. 4" exhaust.
8. Lift pump with some extra filtration, BD, Fuel lab etc.
That's about all I can think of and should be pretty bullet proof.
I own 2 LLY with the 03 LB7 being converted to LLY. Heres my list in order of importance.
1. ice pick all 8 injector plugs, reroute injector wires 2 and 7 so they have some slack and aren't pulled tight against plugs on top of the injector.
2. Cut the zip tie holding the wiring harness to the FICM mounting bracket (silver box right front of the engine, under the air intake pipe), pull it back and make sure there is no bare wire showing from rubbing on the bracket, use a hose guard on the harness and zip tie it back down to the bracket.
3. LBZ or S&B mouth piece, huge problem with the LLY. Many threads on the Pros of this.
4. EGR delete or blocker plate. PCV reroute. These should be done together as the PCV oil and EGR soot really gum up the intake clams and heads.
5. 50-75 hp tune and a boost Pyro gauge, efi live, diablo sport, h&s whatever. Just leave it on one tune, switching tunes all the time just angers the transmission (it's a learning trans, based on HP and driving habits)
6. Shim the Fuel Rail relief valve, or install a race valve.
7. 4" exhaust.
8. Lift pump with some extra filtration, BD, Fuel lab etc.
That's about all I can think of and should be pretty bullet proof.
Thanks everyone for the input. I realize that the knowledge you're sharing is based on problems that some of you may have had to learn the hard way. I'm grateful for forums such as this where others can share their experiences for the greater good. Hopefully one day I will be able to contribute and help someone else the way this group has helped me.
The first 3 I listed are well documented LLY problems, and are must fixes imop... Aside from the Mouthpiece the first 2 are easy and free:thumb:
You might have a lot of problems with that old truck , you should sell it to me now now before you do ! LOL! Great truck and do not plow snow and do not tow too heavy until all the necessary mods are completed , have fun and do not let it go !
Ha! I know, I'm sure I wouldn't have any problems selling it. I'm going to try and keep the miles down so it will continue to be a nice, low mileage truck for years to come. I have a 2500hd gas that is my actual "work truck".