If you think of how many diesel trucks have been produced in the last few decades, it becomes clear just how many used diesels are out there. The fact that many pickups are used as fleet vehicles or work trucks and are replaced every few years, means the market is regularly flooded with fresh batches of slightly used vehicles that are often sold for pennies on the dollar.
Since diesel powertrains have become increasingly complex (and therefore more problematic and expensive to fix), a used truck buyer must be on his or her toes when it comes time to make a purchase. Here are a few of the more common items and problem areas to look for when purchasing your first used diesel truck.
1989 to 1993 5.9L Cummins
First-generation Dodges have more than likely succumbed to rust in the Midwest and Northeast, but there are still quite a few left in the Western states. Keep an eye out for electrical problems when buying these trucks, as well as aged transmissions (both manual and automatic) that might be ready to fail. The good news is these trucks are light, exceedingly simple, and can get excellent fuel economy.
1994 to 1998 5.9L Cummins
The classic hot rod of the Dodge group, second-generation Dodges have a loyal following and not many major issues. Their interiors wear out fast, the headlight switches burn out, and blend doors (for the air conditioning) stop working, but they have very few serious mechanical issues other than the killer dowel pin problem, which also plagues first-generation Dodges. This is a locating pin (installed in the front gear case at the factory) that can fall out and cause damage to the engine, but many high-mileage trucks have already had this problem addressed, and if it hasn’t been fixed, it’s rather cheap to repair.
’99 Dodge Ram 5.9L
1998½ to 2002 5.9L Cummins
The VP44-equipped trucks made from ’98½ to ’02 are fairly reliable, as long as you’re willing to replace the injection pump every 150,000 to 200,000 miles. The lift pumps in these trucks also need to be addressed and can take out an injection pump if proper pressure is not maintained.
’05 Dodge Ram HD 5.9L
2003 to 2007 5.9L Cummins
Newer common-rail Dodge trucks are also fairly problem-free, although injectors are a wear point and are expensive to replace. If you are going to buy one of these trucks with high mileage, plan on replacing injectors sooner rather than later.
1994½ to 1997 7.3L Power Stroke
The ’94½ to ’97 Fords were the first batch of Blue Oval diesels to receive the direct-injection 7.3L Power Stroke. They were also the first trucks to truly pave the way for electronic power-adders in the diesel aftermarket. As is the case with most older trucks, rust can be an issue in humid and salty climates, but (other than stock E4OD automatic transmissions being a weak link with added horsepower) the engines themselves have no problem lasting 300,000 to 500,000 miles with proper maintenance.
’00 Ford Super Duty 7.3L
1999 to 2003 7.3L Power Stroke
If you’re looking for a rock-solid reliable engine and a truck built to tow, look no further than the first go ’round of Super Dutys. They came with an intercooled version of the 7.3L Power Stroke, did away with the problematic Dana 50 TTB front end under F-250s in favor of the Dana 60, and set the tone for the coming age of ever-increasing payload and towing capacities between the Big Three. Trucks outfitted with programmers that tow and see high EGT most of their lives run the risk of cracking pistons, but low-mileage stockers are very reliable.
’07 Ford Super Duty 6.0L
2003 to 2007 6.0L Power Stroke
Perhaps the most maligned of all Fords is the 6.0L Power Stroke. International originally designed the engine (VT365) to make about 245 hp, but the 325hp version found in Ford trucks has been plagued with issues since it was introduced. Turbos that stick, blown head gaskets, plugged oil and EGR coolers, and bad injectors are all common problems on these trucks, and they can be expensive to fix. Many 6.0L trucks are cobbled into running order and then sold, so unless you know the truck’s history, we’d be wary of these rigs. There is also the possibility of spending a few thousand in repairs up front, so keep that in mind when buying. After all the 6.0L’s problems are addressed, they are actually pretty good engines. The Super Duty trucks themselves are well built in our minds.
2008 to 2010 6.4L Power Stroke
By far the easiest to hot-rod of the bolt-on tuner trucks, the common-rail 6.4L Power Stroke can make amazing power (like 550 rwhp with just a programmer and exhaust) and face much less serious issues compared to the 6.0L Power Stroke. However, as these trucks age, high-pressure fuel pumps are dying sooner than comparable CP3 injection pumps (found on ’03 to present common-rail 5.9L and 6.7L Cummins, as well as ’01 to ’10 Duramax engines). Finding a low-mileage 6.4L would still be well worth it in our minds. With the right combination of aftermarket parts, you can have a 550-rwhp play toy that can still tow anything you need it to, and won’t cost an arm and a leg to get there.
’04 Chevy Silverado HD 6.6L
2001 to 2004 6.6L Duramax LB7
Early Duramax-equipped rigs are very good trucks, other than one Achilles heel: common-rail injectors. These early LB7 engines had injector issues and would often fail on a bad tank of fuel, or within 100,000 miles. They’re also hard to get to (located under the valve covers) and expensive to change, but they’re one of the few problems on these early trucks. If the injectors have been changed, make sure they are legitimate Bosch parts and all eight have been replaced.
’05 GMC Sierra HD 6.6L
2004½ to 2005 6.6L Duramax LLY
Although the ’05 LLY model didn’t have the injector issues of the LB7 engine, it had its own problems—mainly in the form of overheating issues during heavy towing. Other than an aftermarket radiator, there’s no real way around this, so if you tow heavy, it might be wise to skip on the LLY- engine model.
’06 Chevy Silverado HD 6.6L
2006 6.6L Duramax LBZ
If an LBZ truck is running funny, we’d definitely shy away. The ’06 engines can crack pistons when pushed hard on high-horsepower tunes, so, like the 6.0L Power Stroke, we’d buy a truck we knew the history of. Other than that, these are solid trucks that can make excellent power (500-plus) when turned up They also came with the six-speed Allison 1000, which could handle more power than the five-speed in previous models.