I might Buy This 2003 Duramax How To UPGRADE a 2003 DMax

**In2Trux** · 03-19-2010, 08:53 AM

I'm looking at buying this 03 Duramax
2003 2500HD
4X4 crew cab auto. LOADED 153,000

I know it's the early generation engine, I forget which engine is in the 2003.
but... I've heard horror stores about the engines.. and I've heard some guys have never had an issue at all.

Question: If I was to buy this ? And I started to notice problems with the performance.
What can I do to this engine to make as good as ... maybe the LLY ???

**Gambit** · 03-19-2010, 08:59 AM

A diesel is so much easier to gain performance out of than a gas engine. Get yourself a cold air intake an exhaust and a hand held tuner from bully dog or some other reputable programmer and you can map out your performnace and have it change to meet what type of driving you are doing. As far as the generation of duramax. The only place i have heard of there being SERIOUS issues with the Gen 1 is here on this site. I have heard of your basic bugs other places but no where bashes the Gen1 like this site that i have seen anyway. What transmission is in it? If it is the Allison i would go for it. but that is me.

**In2Trux** · 03-19-2010, 10:01 AM

Thanks Gambit
Yeah !! all that I was gonna do.. no matter what year truck I bought. especially the hand held tuner.

I was wondering what upgrades Chev did to the first Generation engines?? and could I do them to this engine if it became an issue.

**Joeairforce** · 03-19-2010, 12:45 PM

They did quite a bit of upgrades from Gen 1 (LB7) to Gen 2 (LLY).... The injectors are the only thing I've really heard that make people want to stay away from the LB7's......

Upgrades as far as the LLY goes are... they have different injectors that tend to not go bad, a different turbo (variable vane turbo on the LLY vs a wastegate controlled turbo on the LB7) the heads were re-designed to make getting to the injectors easier (you don't have to pull the valve covers to change the injectors on an LLY like you do the LB7).... (i may have missed some but those are the big ones)

Unfortunately the "upgrades" on the LLY are not interchangeable to the LB7.....