if you are buying at a GM dealership, have them run and print you a VIS report on the truck ( uses the VIN number and will bring up the total vehicle warranty history, reguardless of where it was performed) also ask if there is a service history at that dealership.
'03 Dmax is just as susptable to injector issues as the '01-'02 trucks, but GM has not extended the 200k warranty to them.......yet (warranty on injection system ONLY ) thus, if the truck is over 100k, you will foot the bill for injectors (about $4000 if all 8 are replaced, as is normal course) This is the LB7 DuraMax, first version, not a bad engine overall, the injectors were/are an issue.
I used to work on these trucks, did WAY to much warranty repair to them (is why I no longer do this) and most always was an injector issue. DO NOT let them tell you maybe one or 2 will go bad, that is BS, once one goes, the rest follow suit in short order, seen it TOO many times.
If you want a Dmax, go for the trucks produced AFTER Jan 1 2005, these are equipped with the LLY engine, easier to service injection system, and much more reliable as far as the injectors go (but still a small issue) servicing the injectors on this engine does not require major surgery to perform as the injectors are EXTERNAL of the valve covers (LB7 is internal and a full on injector replacment is book timed at 12.5 hrs, customer pay)
Also, finding a COMPETENT tech to handle any injection issues is pretty tough, as by this point, most are so soured by the warranty screwing they get by GM that they'll slap it out with out reguard to quality. ( GM only pays 8hrs warranty for this job)
wish I could paint a more rosey picture for ya, but this is honesty from experiance
Kevin
