How to Buy a Used Car – Pt. 3: Due Diligence (The Inspection)

Steven Lang
by Steven Lang
how to buy a used car pt 3 due diligence the inspection

You can rigorously apply the tests described by previous installments of this series without encountering a single setback. However when it comes to buying a used car, it pays to assume one simple salient fact: you don’t know the complete truth. At least not yet. When it comes to pursuing the deeper truths about a used car, an experienced mechanic will inevitably become your greatest ally and advocate. For most consumers, finding a knowledgeable mechanic will be the most important step in the used car buying process.

Before we talk about that, I want to be perfectly clear on this point. A used car is guilty until proven innocent. Do not buy one without taking the car for a professional inspection. If the seller doesn’t agree to let you do so, you’re done. Period. No exceptions. Ever.

Now, mechanics tend to divide into three categories: the shade-tree, the Nazi and the diligent professional.

Shade-tree mechanics are hobbyists on limited budgets. Due to the lack of equipment (or experience), they may not be familiar with the unique wear issues and maintenance needs for your vehicle. The shade-tree mechanic will look at the car’s basics, take it for a short test drive and call it good (or “not bad”).

The Nazi will attempt to perform every mechanical test known to wrenchkind, submit the car to a standard of inspection that is rooted in la-la land, and then make you financially fearful of buying anything other than (cough! cough!) one of their vehicles.

Obviously the Nazi is a non-starter. Often times, these party members will work for dealerships (but not always), and are therefore pre-occupied with meeting their service department’s monthly quota of service hours and revenue.

Unless your next car has a prancing horse or bull at the front of it, you’re usually far better off with a diligent mechanic. The diligent mechanic will work through a standard check list, and then take the car for a test drive in a variety of operating conditions.

Diligent mechanics are experienced independent professionals with established roots in your community. To find one, I strongly recommend visiting the Mechan-X files at I also can’t over-emphasize the importance of personal recommendations– especially from people who own the same model of car you’re considering buying. Many small to medium-sized repair shops will post testimonials on their “ego wall.” Read them carefully.

Before the inspection takes place, collate the list of the concerns you created during the test drive. When you deliver the car for inspection, go over them with the mechanic one-by-one. Make sure you both have a clear understanding of all your potential concerns. This will provide a base line for the inspection to follow.

Some mechanics inspect used cars for a set fee. Others charge an hourly rate. In both cases, the post-list discussion should conclude with a confirmation of the probable inspection cost. Leave some leeway; you don’t want the mechanic to stop their investigations for the sake of a few bucks. (Leave your contact number for this possibility.)

The best way to build a healthy relationship with any mechanic is to simply try not to be one of “those” customers. Just let them get on with their job. Don’t stare at the mechanic while they’re doing the inspection. In fact, it’s best to leave the premises entirely. And don’t phone your mechanic two hours later and ask for a status report; wait for their call.

Once the inspection is completed, sit down for a one-on-one debrief with the mechanic (even if you have to come back on another day). I always prefer to speak with the actual mechanic involved in the inspection, or at least have them in attendance with the “service advisor."

First, let the mechanic speak without interruption. Some diligent mechanics will go on for quite some time; some will simply say “here’s my report.” Either way, review the information and let him explain every issue and potential issue to you. After they’re finished, don’t be afraid to say “I don’t have a clue what you’re talking about” or “Is this a sign of normal wear or abuse?”

Make your own list of trouble spots from this conversation, noting down the potential cost to repair, replace or reinvigorate each item, and whether or not the issue is urgent, eventual or unimportant.

Once you’re finished the play-by-play, ask a few general questions. I always ask “Did the owner do a good job maintaining this vehicle?” and “Did the owner use good parts or cheap parts?” Either of these inquiries usually invites a deeper conversation with the mechanic.

If the used car has survived the inspection process without revealing any critical issues to your diligent mechanic, it’s time for the final negotiation with its owner.

Steven Lang
Steven Lang

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  • Corvette Blogger Corvette Blogger on Jun 29, 2007

    Working as I do for a GM Certified Pre-Owned dealership, I have obseved what is sold both certified and not. The certified process is an excellent approach because the factory requires that the dealer prepare the car or truck properly. As an "insider" I think certification is the way to go!

  • Gottleib Gottleib on Jun 29, 2007

    Lumbergh21----of course the lawyer trusted the used car guy, I think they call that professional courtesy. Politicians, well they are somewhat of a hybrid combining the worst of used car salesman and lawyers. If you don't believe me just look at our Congress......

  • EBFlex Will the frame break in half too? That would be the ultimate throwback to the first generation Raptor.
  • Jam65757601 This is a way of saying the VW empire is shaky,
  • RICK Lou, not sure about panthers and Cougars , BUT at 76,I now consider myself a vintage Rolls Canardly. I roll down one hill and Canardly get up the next! Wishing you a Very Happy, Merry HanaKwanzaMas. 🎅🎄
  • Lou_BC The dealbreaker for me is the $80k starting price in Canada.
  • Zipper69 The Grenadier was designed ground up to be a "better Land Rover" and by most press accounts comes close.What little we know about the Quartermaster it's clear that it's intended for serious off road work without additional aftermarket fettling needed.The price is clearly a barrier, but IF it's the real deal, it will have a slot in the market.