what to look for when buying a 6.7 cummins

Buying a Used Diesel Truck: Everything You Demand to Know

June 13, 2018
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Whether the goal is to tow, booty, commute or compete, the endless versatility of a modern diesel truck makes it the do-anything vehicle of the 21st century. No other vehicle affords you the ability to lug 20,000 pounds through the mountains, bear the equivalent of a compact sedan in the bed, glean 20 mpg out of 4 tons of rolling mass or beat upward on the local pony cars at the track without changing a thing. With and so much utility built into them, it'south no wonder diesels have exploded in popularity over the past fifteen years. Everyone wants one. However, not anybody wants to fork over 70K for a new one. Hence the booming used diesel fuel truck market: a smorgasbord full of everything from lightly used/not bad condition candidates to run-into-the ground/basket cases.

So how do you decide if a Ford, GM or Ram, Power Stroke, Duramax or Cummins is right for you? Which model years are more than reliable than others? Which transmission would be better, and should I wait for an automatic or a manual? What types of trouble signs should I expect for on the engine, in the cab or under the body? What trucks should I avoid at all costs? With and so much to consider, finding the perfect used diesel fuel for your needs tin be an intimidating process. Our advice? Read this article then bear your own, extensive inquiry. Speak with owners of each make, model and engine make you're considering, along with people who work on them for a living (they won't sugarcoat anything). Seek out the bad but don't overlook the expert and brand an informed decision.

On a tight budget? Bank check out our article on the best used diesel trucks for 10K!

Thinking of buying an '08-'x Super Duty? Use extreme circumspection and read this first.

Towing Heavy? Buy '11 or Newer

If you're going to be towing heavy, we recommend you buy an '11-newer GM or Ford, or a '13-newer Ram. Reason being, these trucks were built with GCWR supremacy in heed—a war that's always been waged between the Big Three merely that really kicked into high gear in the '11-'13 timeframe. On these trucks you'll find beefier frames and interruption components, torquier engines, exhaust brakes and an all-around more confident towing experience.

Miles Aren't Everything

Remember, miles aren't everything. Especially when looking to buy a used service, utility or fleet truck, engine hours—be it idle time, steady-state highway cruising or finish-and-go metropolis driving—are much more telling than an odometer could ever dream of being. Because 1 60 minutes of idle fourth dimension is equal to 25 miles driven, a truck that has spent virtually of its life idling could have the equivalent of 400,000 miles on the engine but only show 100,000 miles on the odometer. More importantly, a service truck's oil change intervals should be based and performed according to engine hours, not miles. Unfortunately, finding out this information may not ever exist possible and not all trucks have an engine hour meter (specially older models).

Going the Distance (Non for Speed)

This is the bodily odometer reading on an '09 Chevy Silverado 3500 dually equipped with an LMM code Duramax. Its owner tows campers for a living and sets the cruise at 60-62 mph when he'south on the claw. To appointment, an ECM tune geared for maximizing towing performance, conservative driving habits and an adherence to a strict maintenance regimen has yielded no major mechanical failures. Repairs take exclusively been typical habiliment items (bike bearings, U-joints, glow plugs, a water pump, transmission cooler lines, tires and brakes). The factory Bosch common-rail injection organisation, Allison 1000 transmission and engine internals accept gone completely untouched.

Emissions Organisation Failures

Exist forewarned that emissions-related problems run rampant on diesel trucks produced subsequently '07. Due to stricter EPA emissions standards targeting nitrogen oxide (NOx) output, exhaust gas recirculation (EGR) came every bit standard equipment on '03 Fords equipped with the 6.0L Power Stroke and '04.5 GMs fitted with the LLY Duramax. A few years later, another regime push for cleaner emissions (this time for reduced particulate matter) resulted in Ford, GM and Ram saddling their engines (the 6.4L Power Stroke, LMM Duramax and 6.7L Cummins, respectively) with a diesel fuel particulate filter (DPF) in add-on to EGR. The latest pollution-fighting method (farther targeting NOx reduction), selective catalytic reduction (SCR), was added to the mix on '11 model year Fords and GMs, while Ram added information technology to its 2500 and 3500 trucks in '13. To date, EGR, DPF and SCR systems remain the virtually common causes for breakdowns, reanimation and hampered performance on belatedly-model diesels.

EGR

Even though they were designed to part in a harsh working environment, no EGR valve and/or cooler volition terminal forever. In fact, even the newest diesel trucks on the market can experience an EGR-related failure well inside of 100,000 miles. If yous're buying an '08 or newer diesel with all of its emissions systems however intact, simply know that some of these components will likely demand to be replaced and that they're not particularly cheap. Information technology's also of import to know that EGR contaminates the engine oil, reduces the size of the intake tract and even the cylinder heads, not to mention that it'south hard on the engine coolant, whose job it is to turn 1,000-plus caste oestrus into 300-degree air used for reentry into the intake.

Rust: The Slow Killer

With engines capable of living most forever, it's the rest of these trucks you'll need to worry about, namely rust. Finding a make clean candidate is key, which makes southern and western climates the ideal hunting ground. Some surface rust underneath is OK (and is likely unavoidable when dealing with 10 to 15-yr-old trucks), but make sure you're non ownership a vehicle with structural components that've passed the point of repair (i.e. bubbling fenders, breakable leaf spring shackles or hangers, dilapidated radiator cadre supports, etc.). Check the inside of the frame, non only the outside. Also, never buy a truck sight unseen. This can be a unsafe game today with then many truck sales taking place online, but we would never commit to buying until we could inspect the vehicle in person.

Break out the Fine-Tooth Comb

While replacing items such as body mounts, U-joints and leaf spring bushings aren't tall orders for the average truck guy, if you're looking for a turn-central used diesel fuel truck steer clear of something like this. This rusted torso mount has been painted over in an effort to embrace upward the extent of its dilapidated status, potentially to deceive a prospective buyer.

Paper Trails Are Good

Any time the possessor hands over a folder full of service receipts, information technology'due south a skilful sign that he or she has maintained the truck appropriately. Keeping detailed records shows that the previous owner truly cared about the truck—and if you want to unload the same truck one 24-hour interval it behooves you to go on adding your ain receipts to the vehicle's credible paper trail.

LB7 Injector Bug

Every bit a pre-emissions engine (meaning no EGR, DPF, SCR or even a variable geometry turbo), the LB7 Duramax found in '01-'04 GM HD trucks is the simplest and arguably the virtually reliable of the bunch. However, its one major flaw exists in its mill injectors, which are predisposed to failure. Specifically, the injector bodies crack, leak and dump excessive fuel in-cylinder, which causes a constant brume out the tailpipe. With the injectors beingness located beneath the valve covers on the LB7 (not the case on LLY and later engines), injector replacement is neither cheap nor easy. Although improved injectors now exist for the LB7, injector replacement is something almost no Duramax-equipped GM built between '01 and '04 tin can escape.

High Miles and Programmers

With aftermarket programming capable of calculation more than 200hp to some diesels, it'due south no wonder most trucks are interfaced with a tuner. Unfortunately, this takes its toll as older trucks rack up the miles. After coping with the added cylinder pressure, boost pressure and drive force per unit area for tens of thousands of miles, things usually culminate in a blown head gasket. This is especially true for tuned Duramax and Power Stroke mills, but information technology furnishings the Cummins crowd, too.

Bad Vibrations

The passage of time coupled with thousands of miles of vibration can yield chafed wire harnesses on whatever used diesel truck. Intermittent curt-to-ground scenarios run amuck on older Duramax and Power Stroke engines, specially. Although it'south usually an easy fix, electrical gremlins tin make for some time-consuming troubleshooting for whatever technician.

More Torque+More than Cylinder Pressure=Lift-Off

Due to its increased bore and stroke over the five.9L (i.due east. higher cylinder pressure and torque production), a 6.7L Cummins is twice as likely every bit the 5.9L to accident a head gasket. Many 6.7Ls make it roughly 200,000 miles before lifting the head, while tuned engines and/or ambitious performance tin induce head gasket failure much sooner.

Chrysler Automatics

If you lot're looking for a Cummins-powered Ram, from any model year, you'll be coin alee by finding 1 with a manual transmission. From the NV4500 to the NV5600 to the G56, it's hard to go wrong with any of the standard shift units available in Ram trucks from '94-nowadays day. It's the automatics you lot really have to worry about. Even at stock power levels, reliability of the Chrysler 4 speeds (47/48s) and the latest six-speed (68RFE) autos is questionable while towing heavy. Bring a developer into the mix and bulldoze aggressively and you lot're on borrowed time. If you have to have an motorcar, nosotros would build the fact that y'all'll eventually have to beef up or replace the manual into the toll you offer for the truck.

6.0L Power Stroke Warning

For years, people have been lured into buying used '03-'07 Ford Super Dutys by depression resale prices and because they tin can exist "bulletproofed." We will start by saying that these trucks are cheap for a reason—and no engine can be bulletproofed. There are a lot of problems that volition either occur in fourth dimension or need to be addressed right away on a six.0L. EGR issues run rampant, the oil coolers plug upwardly, caput bolts stretch, turbos stick, FICMs fail and the high-pressure oil injection organization is nowhere near as reliable as the system employed on the 7.3L.

The half dozen.0L: A Approving In Disguise (If You Tin can Wrench)

That said, if you're mechanically inclined, yous can salvage yourself a lot of coin past picking upward an '03-'07 truck on the inexpensive and repairing it yourself. Y'all'll save coin over ownership whatsoever other make or model congenital in this era and also finish up with a used 6.0L that's pretty darn reliable. Almost people run away from these things, but if you're large on regular maintenance and an higher up-boilerplate wrencher, you tin continue ane on the road indefinitely.

Beware the Gauges

Even if it's not equipped with a programmer when you're looking it over, nine times out of 10 a truck that's equipped with gauges is or was treated to some sort of electronic power adder. Added power ways the engine was subjected to more heat (namely exhaust gas temperature), added stress (i.due east. cylinder pressure level) over manufacturing plant levels and that the transmission behind it was also likely exposed to supplemental abuse.

Inspection Pointers

Check for excessive blowby (cylinder wall, piston, piston ring wellness).
Check for white balance on the coolant overflow reservoir/degas bottle (indicative of a blown head gasket).
Bank check for worn ball joints, inordinate amounts of rust and oil, fuel, coolant or transmission fluid leaks.
Inspect how dirty (or clean) the air filter is.
Don't accept any answer for why a Bank check Engine Light (CEL) is illuminated unless y'all tin can read the code yourself.
If possible, witness a cold start.
Listen for whatsoever type of lope or miss at idle and when dropped into gear (could be the sign of an injector issue). If you lot hear any noises that bother you lot, consider it a worst example scenario and walk away.
Pay attention to how long it takes for an automatic transmission to engage afterward making your gear pick.

Model-Specific Tips

Dodge

'94-'98 Contrivance Ram 2500/3500:

Inquire if the "killer dowel pin" has always been addressed (the factory-installed, pressed-in pin is known to dislodge and fall into the crankshaft and/or injection pump gears).

'98.5-'02 Dodge Ram 2500/3500:

Notice out if the VP44 injection pump and/or factory elevator pump has always been replaced (an ailing lift pump tin can kill the VP44, and well-nigh VP44s don't make it past 150,000 miles).
Find out if the engine utilizes a "53" block (known to cleft in thin water jacket areas).

'03-'07 Contrivance Ram 2500/3500:

High-pressure mutual-rails injectors and injection pumps aren't inexpensive, so brand sure merely properly filtered, fresh fuel makes it to them.

'07.5-present Ram 2500/3500:

Head gasket failure is common around the 200,000-mile mark, primarily due to the vi.7L Cummins' generation of immense cylinder pressure (i.e. torque).

GM

'01-'04 Chevy/GMC Silverado/Sierra 2500/3500:

Ask if the original injectors accept been replaced (the OEM units are known to crack).

'04.five-'05.five Chevy/GMC Silverado/Sierra 2500/3500:

Overheat scenarios are common when towing heavy with the LLY Duramax (much of this can be alleviated with the addition of a larger turbo inlet manifold and an external oil libation).

'06-'07 Chevy/GMC Silverado/Sierra 2500/3500:

Like all Allison-equipped GMs, the A1000 automated transmission won't tolerate significant power gains provided by an aftermarket programmer (an extra 120hp seems to exist the limit of the '06-'07, six-speed Allison).

'07.5-'10 Chevy/GMC Silverado/Sierra 2500/3500:

Ask if the mill transmission lines have always been replaced (they are prone to leaking, especially in colder weather) and if the truck has experienced any DPF-related (emissions system) issues.

'11-'16 Chevy/GMC Silverado/Sierra 2500/3500:

Beware that emissions organisation-related failures (DPF, SCR) are fairly common, and CP4 injection pump failure can exist catastrophic (ofttimes self-destructing and taking out the injectors with it).

Ford

'99-'03 Ford F-250/F-350 Super Duty:

Ask if the camshaft position sensor has ever been replaced (its failure tin leave the vii.3L dead in the h2o).

'03-'07 Ford F-250/F-350 Super Duty:

Notice out if the truck has ever had its oil cooler, EGR cooler, EGR valve, injectors or turbo replaced (all are prone to premature failure), and whether or not it's ever been treated to new caput gaskets (and hopefully caput studs).

'08-'10 Ford F-250/F-350 Super Duty:

Make up one's mind whether or not the truck has ever had its oil cooler, EGR coolers, DPF, turbo upwards-pipes or radiator replaced.
Warning: Fuel contamination is a major concern with the 6.4L Power Stroke, which can lead to extensive and expensive injection organisation repairs.

'xi-'18 Ford F-250/F-350 Super Duty:

The turbocharger on '11-'14 models is infamous for early retirement.

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Source: https://www.drivingline.com/articles/buying-a-used-diesel-truck-everything-you-need-to-know/