What to look for in buying used.

[dk2429]

I posted a while back on which year of DMAX I should be aiming for for my first diesel. I'm ready to really start looking now.

Simple question is, what in general is there to look for in these trucks when buying used? With my price range I'll most likely be ending up with an LB7 or LLY. Never have owned a diesel, just looking for some general stuff to look at when buying these trucks.

Thanks

 

[zakkb787]

As a diesel newbie you really should get an LLY. Lb7 are a great motor but the injector issues aren't for the new or faint of heart. Mainly how well it's been taken care of. Whether or not it's been upgraded in any way. How it shifts. Suspension condition. Things like that

 

[TheBac]

Can you do your own maintenance/repair work?

LB7 will have injector issues as stated above, other wise solid engines. LLY also have injectors fail, but at least you can just replace the individual ones when they do, not an entire side/set. Some LLYs also have overheating issues. There are many ways to deal with that, though.

Guess its completely up to you which way you decide to go.

 

[dk2429]

I am mechanically inclined, however, I'd also prefer to have an LLY after doing my research, but if I find an LB7 for the right deal I'll go with it.

For the overheating issues with the LLY, I'm not too worried about that. I'll be doing a lot of towing, but nothing heavy enough to cause that issue. 2 main things I'll be hauling is a 3500-4000 pound boat, and a ~6500lb RV, but 90% of the time the boat. Also, I live in SE Texas, so most of our grounds are pretty flat unless when I go fishing up in East Texas or South Texas. Even then, the grades are not near what they'd be like say up in Wyoming/Montana.

I know to look for blow by on diesels, but not much more than that. Is there anything else to look for in the engine itself besides just blow by?

Just curious, how often would you typically expect the injectors to go out in an LB7? I'm sure it's just deal where they go out when they want to, but what's the typical mileage intervals to expect this?

 

[zakkb787]

Really depends on your quality of replacements. But I'd say no less than 70k. Maybe tom will pitch back in and correct me if I'm wrong. Plug in a scan tool and see if there are codes present and read the injector rates. All should be close to 0 if it's healthy but anything beyond +/-4 is bad. Also check desired vs actual rail pressure

 

[Pure Diesel]

I am mechanically inclined, however, I'd also prefer to have an LLY after doing my research, but if I find an LB7 for the right deal I'll go with it.

For the overheating issues with the LLY, I'm not too worried about that. I'll be doing a lot of towing, but nothing heavy enough to cause that issue. 2 main things I'll be hauling is a 3500-4000 pound boat, and a ~6500lb RV, but 90% of the time the boat. Also, I live in SE Texas, so most of our grounds are pretty flat unless when I go fishing up in East Texas or South Texas. Even then, the grades are not near what they'd be like say up in Wyoming/Montana.

I know to look for blow by on diesels, but not much more than that. Is there anything else to look for in the engine itself besides just blow by?

Just curious, how often would you typically expect the injectors to go out in an LB7? I'm sure it's just deal where they go out when they want to, but what's the typical mileage intervals to expect this?

There are no specific miles that the injectors last. Got a friend with an 03 LB7 and 340k miles. Still has the original injectors and just does maintenance. Me, I went through 4 sets in 115k with maintenance to the tee. My 06 LLY/LBZ transplant has 160k and still the original injectors. I have put 45K of the 160K. Its hit or miss on the LB7 injectors.

 

[Ne-max]

You get what you pay for........ Even though 200000 miles is not a lot of miles for a diesel, the rest of the truck gets wore out.

 

[lts1ow]

You get what you pay for........ Even though 200000 miles is not a lot of miles for a diesel, the rest of the truck gets wore out.

This.

Make sure you check all the front end for sloppiness. My friend got his 05.5 with a top A arm barely hanging on and the owner just shrugged when we told him. People are rather dumb sometimes when its maintainace time.

Try and check for any evidence of rigging electrically etc, those home jobs can be a nightmare to fix later on

 

[dk2429]

Thanks guys! I'll keep it all in mind. I'm really aiming to find an LLY with under 200k miles. I'll keep looking until find her!

 

[torqued2dmax]

Just be advised , if you put a big tune to it and run it hard often in big tune , in 5th , head gaskets ,studs machine shop to clean up heads,shift kit and torque converter mim.I am sure there are a some guys that have gotten away with 150 rwhp tunes towing in 110 heat up hills pulling 10,000 with noooo problem , but not me , GOOD LUCK! keep us up it date .

 

[dk2429]

I'm keeping my truck BONE STOCK.

I guess this would be a good time and ask.. Just know, this is my opinion, and the way I look at it. I've never owned a diesel, so I probably don't know what I'm talking about..

What is the point in folks putting programmers/tuners/chips on diesels to shoot them an extra amount of HP? I've grown knowing diesels are made to tow heavy and work, and they come from the factory ready to do just that. My truck will be used for towing, so I don't need a tuner to floor it and see how fast I can get it to go.

Just curious, I apologize if I offended anybody. I'm learning

 

[zakkb787]

Tuners can change more things than just power. A good tow tune can make your truck tow completely different. Get better mileage. Many many things can be done with a good custom tune.

 

[torqued2dmax]

Head gasket issues can happen tuned or not , just be aware and deal with it if it happens , dont let it keep you from owning a great truck . Good luck!

 

[dk2429]

Head gasket issues can happen tuned or not , just be aware and deal with it if it happens , dont let it keep you from owning a great truck . Good luck!

Yeah I understand that, it's just when you mentioned the tuner deal I figured I'd go ahead and ask what the deal is with tuning these trucks and putting all that after market stuff on them when they're ready to go as is.

 

[zakkb787]

Truth is they're not really as ready to go as they should be. Many things can improve not only power but also longevity. Fuel mileage. Durability. All sorts of things can be improved greatly

 

[torqued2dmax]

Many of us have kept logs on the improvements each thing we do to our trucks .When i first got mine it got 14 mpg and sluggish , now it gets 20 mpg and can tow anything and outrun many sports cars , I know childish for someone pushing 70 but I cant help myself its a disease !

 

[TheBac]

I'm keeping my truck BONE STOCK.

I guess this would be a good time and ask.. Just know, this is my opinion, and the way I look at it. I've never owned a diesel, so I probably don't know what I'm talking about..

What is the point in folks putting programmers/tuners/chips on diesels to shoot them an extra amount of HP? I've grown knowing diesels are made to tow heavy and work, and they come from the factory ready to do just that. My truck will be used for towing, so I don't need a tuner to floor it and see how fast I can get it to go.

Just curious, I apologize if I offended anybody. I'm learning

That is your choice. Just keep in mind that this is a Duramax Performance forum, and that is the view most of us take.

 

[Budneeds2beers]

You'd be surprised what a lbz mouth piece and a turbo back exhaust will do to a lly. Add a good tow tune with turbo brake and a tap shifter and towing becomes awesome. Just watch temperatures with the lly.

 

[zakkb787]

You'd be surprised what a lbz mouth piece and a turbo back exhaust will do to a lly. Add a good tow tune with turbo brake and a tap shifter and towing becomes awesome. Just watch temperatures with the lly.

Bingo.

 

[lts1ow]

Basic bolt ons and a canned tune nets my truck ~18.5mpg with mixed driving. Tune comes down when I tow with it, but if you plan on owning the truck for awhile, a mpg here and there can def pay off.

(least thats what I tell myself. :rofl