What to Look for when Buying a Used Diesel Pickup

Buying a Diesel Pickup Without getting Taken

Hello everyone.

Today I would like to talk about buying a diesel pickup. Specifically a used pickup, but I will include some thoughts on new trucks as well.
    While I myself specialize in medium and heavy trucks, the company I work for has several customers with fleets of from a handful to several dozen light duty trucks (pickups). When I talk about a light duty vehicle I am talking about those up to around 12,000 GVW (gross vehicle weight).
    Engines include the Ford 7.3, 6.0, (made by International/Navistar) and 6.4 Powerstroke, the GM Duramax (Isuzu), and Dodge (Cummins) 6.7

Do you really need a diesel?

    The first and foremost caution before you even start looking is to decide whether you really need a diesel powered truck. Do you tow or haul a significant load on a regular basis, or do you just want the status of driving a diesel? Keep in mind that a diesel will cost much more than a gas engine to buy, and much, much more to keep up and to repair. In the coldest weather it will need to be plugged in if you expect it to start, and the newest models require periodic refills of Diesel Exhaust Fluid in addition to fuel. This may not be much of an issue when the vehicle is under warranty, but if it is a used truck or you intend to keep it a long time, it should be seriously considered.

A check engine light is a red flag

    The first thing I will caution against is to NEVER buy one of these vehicles that has the check engine light on. I will stress this again, because it is that important. If the engine light is on or comes on after a 10 mile test drive, WALK AWAY and DO NOT LOOK BACK, no matter how minor the owner tells you the problem is. If it was a cheap repair, he would have done it before trying to sell. Modern diesels can set a light for bad injectors, mechanical problems, and emissions issues among other things, and all these things are expensive to repair.
    I can't tell you how many times we have customers come in having just bought a truck for, say, $3000 and find out it will cost another $2000 - 3000 to get the light off and get it to run properly. I am not exaggerating this problem, a turbo or set of injectors would START at about that much money.
    Engine component accessibility on GM or Ford truck especially, is absolutely horrible, and it gets worse every year as more is added to the engine bay area. Many models are also prone to exhaust and/or oil leaks.
    Parts costs can quickly add literally thousands of  dollars to a repair bill, and you don't really want to install cut rate parts, then have to pay another labor bill to replace them if they fail.

Three things to look for on a used diesel

    For these reasons there are several things to remember when looking at a truck. First, is the odometer mileage appropriate for the model year? The more miles the truck has on it, the closer it is to needing a major repair. Give the vehicle very little extra credit for being meticulously maintained or looking better than the mileage would indicate; neither of these conditions is nearly as important as you might think they are. We see some awfully pretty trucks with serious problems.
    The second thing to look closely at is the engine compartment. I stress looking very closely for evidence the engine has been worked on. Are any screws or other fasteners missing? Are all electrical connectors and sensor attachments intact and undamaged? Are any of the plastic parts broken off with missing mounting tabs? Does anything look like it has been glued or patched? All these things might indicate that there might have been a major repair.
   The third major checklist item is the road test. Never buy a vehicle without taking it on a long test drive. You need to drive it far enough to be sure it gets up to operating temperature and that there are no driveability issues at any temperature or engine speed. The engine shouldn't smoke any more than the occasional puff when accelerating, and it certainly shouldn't smoke at idle once warmed up. It goes without saying that there should be no unusual squeals, whistles, rattles, or knocks at any time.
    Lastly as with any vehicle, don't fall in love with a paint job or fancy doodads bolted to the truck. If it doesn't pass the above tests it isn't worth buying and you should move on to the next seller. Used pickups just aren't that hard to find.

Don't buy a pickup with a chipped ECM

    One word before parting: I suggest not even bothering to look at a truck that has been "chipped" or has other significant power upgrades beyond the stock setup. Despite what anyone or any aftermarket company says, the ONLY way to make  more power is to burn more fuel. A chip or specialty ECM will merely add more fuel, make more smoke, and possible reduce reliability.

Thanks for reading,
Bruce