Buying Used? What To Look For

Used truck buying tips through a mechanic’s eyes

November 2017 Feature Kyle Parham

Buying a used truck can be scary, especially when you don’t know who you’re buying it from. Typically a large dealership is your best choice, but that’s not always an option. Major dealerships will not sell old worn-out trucks due to customer satisfaction and safety. Small or large used truck dealers who are not affiliated with a large corporate organization such as Ford, Chevrolet, or RAM are worth consideration, but I wouldn’t necessarily recommend it. Some used truck dealers will sell you anything they can to make a dollar and often buy what a major dealership will not sell and just “Band-Aid it” to get it on your driveway. I’ve seen a lot of questionable work to get a truck through auction then bought by a used truck dealer, bandage some more and sold to you, the consumer. As a mechanic at Biggboy Auto Repair in West Palm Beach, FL, in my opinion the private seller is my first choice, but either way you need to always proceed with caution.  

Just Needs A Sensor

I’ve seen sockets welded to tips of rocker arms to cover up a collapsed lifter in a 5.9L Cummins; it lasts a while if done right. I’ve seen NOx sensors unplugged so the regen cannot complete so the customer would buy a truck on the fact that it needs a NOx sensor and then they find out about the bad particulate filter.

What Gasket Problem?

I’ve seen the coolant cap that has been broken so no pressure will build in the cooling system. That fixes head gasket problems on 6.0L instantly—that is, if they’re not already completely blown. It will also cover up the water pump on a Duramax. That’s a $2,300 job and $1,100 job you get to pay for if you didn’t catch before you bought.

Check Light, Check Truck

If the batteries are dead or the check engine light is on, take it to a dealership for inspection. I’ve seen a lot of people finance trucks with the promise they are perfect when they are not. Or the oil pressure gauge moved closer to the oil filter on a Chevy so the gauge stays in the normal range, but you’re losing the pressure near the lifters. Almost any small lower-end engine knock can be covered up with enough Lucas.

Just Add Lucas Oil Products

I’ve seen a 6.4L Power Stroke with a completely worn-out rear main bearing but the seller put so much Lucas in it that the truck ran through inspection and was passed by a tech. It was almost sold, but luckily it locked up on a test drive before it could be sold.

Level Check

Look for wiring harnesses exposed and improperly routed, as well as the fluid level incorrect and dirty. High fluid level is a bad sign; it shows that more than likely someone inexperienced worked on it or another fluid is mixing with it. Too low, then there is a leak that’s been cleaned or unseen. Coolant jugs with a ring around the top are usually caused by oil or fuel in system. Wrong coolant can unglue injector cups over time and eat away your engine block.

Close Inspection

If you’re buying a diesel for the first time, they can become a money pit if not bought with caution. I’m a Ford master tech and I’ve seen the worst as well as the best, so be sure not to buy the worst by trusting someone who makes commission on you buying a truck. Take it somewhere knowledgeable about your brand and when in doubt get whatever you’re buying inspected. If you have $20,000 to spend on a truck, take it to a dealer and for $150 or so you may end up saving $19,850!


Biggboy Auto Repair


Lucas Oil


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