5 Used Car Mechanical Checks to Never Forget

Buying a used car can be a stressful experience. After all, your car is one of the biggest purchases you’ll ever make—second only to purchasing a home. The stress level is often compounded by a pushy salesman, doused in cologne, buzzing in your ear. Price haggling and mounds of paperwork can also make you sweat like a summer afternoon in Arizona. Distractions abound, and you can easily forget to check the basics.

That’s why we’ve compiled a list of mechanical checks to never forget when inspecting a used car. Just keep this list handy and you’ll have no problem distinguishing a cream puff from a lemon.

Check under the hood

This is one of the most important steps when performing a pre-purchase inspection. Check all of the accessible fluids—not just the engine oil. Uncle Bob probably warned you to check the oil in that 1995 Dodge Neon you drove to college. But he may have forgotten the rest of the fluids.

When inspecting your future ride, you’ll want to take a look at the coolant, brake fluid, power steering fluid and automatic transmission fluid. Some modern vehicles have electric power steering and lack a dipstick for the transmission, but check what you can. While you’re poking around under there, you’ll also want to check for fluid leaks.

It’s harder to check fluids on a piping hot engine. Hot exposed metal can reach temperatures hot enough to burn errant hands, and opening a hot radiator cap could burst off and cause severe injury. Before your test drive, pop the hood while the engine is still cool.

All of the fluids should be filled to their full marks and clean. You can read up on how to check car fluids, but in general, this is what good fluids should look like:

  • Oil: should be honey colored. It should not smell burnt
  • Brake fluid: should be clear to honey colored
  • Power steering fluid: should be honey colored
  • Transmission fluid: should be pink and not smell burnt
  • Coolant: should be green, yellow, blue or red depending on the manufacturer

Pay attention to the gauges

Not all drivers pay close enough attention to their vehicle’s gauges. Gauges aren’t just there to light up and look pretty—they provide valuable information about the health of the vehicle.

During the test drive, pay particular attention to the oil pressure and temperature gauges. Allow the vehicle to reach operating temperature and drive it at different speeds and on a variety of roads.

Be sure to idle the car and observe its behavior. Engines are more prone to overheating at idle and low oil pressure is also more likely to be apparent. This is because the oil pump is driven off either the crankshaft or camshaft, meaning the oil pump turns faster at higher RPMs, and builds more pressure.

Listen for noises

Turn off the radio and instead listen to what the car has to say. Listen for clunks, rattles, groans and any other abnormalities. Make sure to test drive the vehicle at various speeds, both in town and on the highway. Some of the most important noises to listen for include:

  • Engine noises: knocking, rattling, or pinging from the engine indicate potential big-time problems.
  • Transmission noises: whining, growling or rattling noises from the transmission area could quickly empty your pocket book.
  • Differential and transfer case noises: whining or growling noises from the rear end and/or transfer case (if the vehicle is a four-wheel drive) are a very bad sign.

Like a toddler before bedtime—when it comes to cars, quiet is good.

Check the vehicle history

A Carfax report will provide insight as to whether a vehicle has been in an accident, if it has a clean title and how many owners it’s had. Don’t buy a used car without one. Here are few Carfax traits to avoid when selecting a vehicle:

  • Salvage title vehicles: it should come as no surprise that salvage title vehicles (a vehicle has been damaged and/or deemed a loss by an insurance company) ought to be avoided like gas station hot dogs. Stick with clean title vehicles, which are those that have never been in an accident where the damage exceeded the vehicle’s worth.
  • Vehicles that have been in an accident: no matter how well the vehicle has been repaired, no bodyshop guy has the precision of an assembly line robot. Accidents often cause structural damage to the car that is hard to find
  • Vehicles that have had more than three owners: if you’re buying a late-model car that’s less than five years old, it’s best if it’s had fewer than three owners. A car that’s been around the block is more likely to have been abused. Plus, the fact that no one wants to keep the thing should raise some eyebrows. What’s wrong with it? It is it a lemon? Don’t ask questions, just pass and move on to the next vehicle.

Check the undercarriage

Unless you’re buying a truck or SUV, you probably won’t be able to get completely under the vehicle for a lookie loo. However, you should still make a point of getting down to peek under the vehicle, looking for fluid leaks and damaged parts.

While you’re at it, take a look at the condition of the tires. After all, paying for a new set of tires is an ugly expense after shelling out significant money for the car itself. Tires should have at least 5/32” worth of tread (2/32” is the minimum to pass safety in most states), should be free of sidewall cracks and bulges, and should have a production date less than 10 years old. On all tires produced since year 2000, the last two digits of the DOT number listed on the sidewall will list the production date. For example, in the image below, the tire was manufactured in 2007.

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Image courtesy of TireRack.com

There you have it: the five mechanical checks you never want to forget when buying a used car.