The Used Car Checklist

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It’s always a good idea to have a used car you’re thinking about buying checked out by a mechanic before you buy it. But you don’t have to be a mechanic to do a few basic checks yourself – checks that can uncover red flags about the car’s condition and prior treatment. Find several of these, and you can save yourself the trouble of paying a mechanic to dig deeper – because you already know the car’s probably a stinker. For example:

* Oil check –

Most people know to pull the dipstick to check the condition of the engine oil. Black oil – or a tarnished dipstick – indicates few and far between oil changes, which suggests rough treatment of the engine. But keep in mind that it’s fairly easy (and inexpensive) for a seller/dealer to change a vehicle’s oil just before putting it on the market. And it’s not hard, either, to wipe off/clean off a tarnished dipstick to make it look like new – and give you the impression the car was well-maintained. And it may have been. But you want further confirmation.

*  Brake/clutch fluid check –

An oil change is easy; flushing out the brake lines/master cylinder (and clutch slave cylinder in manual transmission-equipped cars) isn’t. It’s also both important routine maintenance and – if not done – a strong indication the car wasn’t well-cared-for.

Fortunately, checking is easy. First, find the brake master cylinder. It is usually mounted on the firewall, driver’s side. It will typically have a plastic/translucent reservoir and a screw on (or pry off) lid. Open the lid and look inside. If the brake fluid is other than a light honey-color it is probably contaminated and the entire system is due for a flush at the very least (not cheap, by the way). If the fluid is dark, it’s a big red flag. It’s probably very old – and very contaminated. This not only suggests poor maintenance, it increases the chances you’re facing costly repairs if you buy the car. Failure to regularly change out the brake fluid can ruin the ABS pump (in cars with ABS brakes, which is almost every late-model car) among other big ticket items. Watch out. The same goes for the clutch fluid reservoir, which is usually mounted somewhere near the brake master cylinder. All modern cars with manual transmissions have hydraulically assisted clutches. The system uses brake fluid and it must be changed out regularly, too – for the same reasons. Look in the reservoir. If it is dark/dirty looking, at minimum, the fluid will need to be flushed/replaced with fresh fluid. And it’s entirely possible more work – and more expense – will be involved.

* Radiator check –

Here’s another good place to search for clues as to a car’s prior life – and for possible red flags. With the engine cold (be sure!) open the radiator cap and take a look in there. The coolant should be bright green (or red-orange, in some cases) but never brown or (much worse) oily. Brown coolant indicates old coolant that should have been replaced and wasn’t replaced; oily coolant indicates engine problems – and is your cue to say “thanks for your time” and walk way.

Like engine oil, though, it is fairly easy to change coolant prior to sale. You want to look a little deeper. Specifically, you want to look inside the radiator at the lattice structure that the coolant flows through. Assuming the coolant is not opaque (and if it’s fresh it should not be) you should be able to clearly see the first few rows of the internal coolant passages. These should be free of scale and build-up. If they appear clogged up, even partially, the radiator may need to be replaced – and the car may have been running hot, which amounts to abusive treatment. Red flag. At the very least, you’ll want your mechanic to give the entire cooling system a complete work-up before you commit to buying.

* Transmission fluid check –

Find the dipstick for the automatic transmission and pull it out. It usually has a red handle or is otherwise marked. The fluid should be translucent reddish (typically; there are other colors – but the colors are never black or brown) and not smell burned. Here, too, it is possible the fluid was changed out just prior to putting the car on the market. But it’s something you want to check anyhow because if the fluid is brown or black then you know the car’s not for you – unless you’re ok with the high likelihood it will need a new/rebuilt transmission in the near future and on your nickle. If the fluid looks – and smells – ok, you can further ease your mind by getting in, starting the engine and taking note of what happens when you move the gear selector from Park to Drive and then from Drive to Reverse. The transmission should engage almost immediately. If there is any significant lag between the time you move the gear selector from one range to the next and engagement of the gear chosen, it’s a red flag. Take the car for a drive. There should be no sensation of slippage as you accelerate and each gear change should be positive and free of any clunking or other obviously not-normal sounds. Get out on the open road and floor the gas pedal. This is an important test of normal transmission function. The unit should shift down to the next lowest gear and the car should accelerate normally. If there is any hesitation, or (worse) the engine seems to rev but the car doesn’t seem to be responding , you’ll want to make sure an expert mechanic gives the transmission a very close once-over before any money changes hands. 

* Body check –

It is harder to immediately notice evidence of a prior wreck these days because of much better color-matching by auto body shops. However, there are still often clues, especially signs of respray (overspray) underneath the car, or in the inner fenders, around weatherstripping and exterior trim/badges – which are often not removed before a car is painted but just masked over. Closely eyeball each fender, each part of the car, for signs of respray and if you find any, ask the seller about it. It might have been a minor fender bender and so no big deal. But if it was a major accident, it’s possible the car has leaks or squeaks or problems much worse than that. Either way, you want to know what’s up before you come to terms. It’s another thing to mention to your mechanic, if it gets to that point.

* Paperwork check –

You want to be sure the seller has a clear title to the vehicle – and ideally, that the title is in the seller’s name (if it’s a private party sale). Not all “curbstoners” – people who sell used cars on their own, but who are not dealers – are shady. But some are and it’s good reason to be wary. Generally, be on your guard if the seller is “selling it for a friend.” Reason? In the event there’s some problem, you’ve got less recourse than you would otherwise because the seller wasn’t legally the previous owner. Also, curbstoners are pros. So are dealers, of course. But dealers are more restrained by dint of being more accountable. They have a physical storefront, a formal business. The curbstoner you just bought that lemon from can easily just vanish and leave you holding said lemon.

So, be careful.

Even better, be suspicious.










  1. I know this is an old article, but I’m test driving a car tomorrow, and this has given me quite a bit of help. So thanks!

    But one thing, not sure if I can check the transmission by flooring it, as my mom will be with me. 🙁

    • Is it a manual or an automatic?

      If it’s a manual, the shifter should move through each gear smoothly with the clutch pedal depressed (car at rest, engine idling). The clutch should engage smoothly, without jerking (or slipping). Each gear change (while moving) should also be smooth and free of gear grinding (assuming the driver can drive a stick!). Put it in fourth gear at a relatively low speed (30 or so so) and give it full pedal. If the clutch is bad, you’ll notice slippage; the eengine revs but the car seems like it’s not picking up speed. You might smell something that smells acrid/burning – that’s clutch material.

      If it’s an automatic, you should feel an almost immediate positive engagement as you put it in Drive from Park or Neutral. Same with reverse. Accelerate from a stop. The car should move forward crisply and through each gear, from first to second, second to third and so on. Be sure to pull the transmission dipstick in the engine compartment. The fluid should be (usually) red-orange. If it’s brown or black or smells burned, it’s a sign the unit overheated and/or hasn’t been serviced in a long time.

    • Hi Larry,

      Checking the tires – including condition – is of course a good thing to do, too. But wear is not necessarily indicative of miles. For example, many late model cars come with soft-compound sport tires that will wear out in less than 15,000 miles if the car is driven aggressively. So, if you were looking at such a car with say 17,000 miles and it had brand-new tires on it, you might wonder why and worry that the odometer had been fiddled with when in fact it’s only that the tires were recently replaced.

      • When it comes to tires, check wear patterns, too. Uneven wear could indicate everything from needing an alignment to suspension problems. In addition, wear in the centers means overinflation and wear on the edges means underinflation, which could point to overall neglect/incompetent maintenance.

        Don’t forget an interior check. Use your nose to check for musty/burnt smells, which could mean leaks, wiring problems, that previous owners smoked it out, or heaven forbid, flood or fire damage. Check seats and pedals; well-worn seats and pedals and a low odometer reading could mean inaccurate/fraudulent mileage. Check carpets; a carpet that is recently replaced could mean anything from a big-time coffee spill to flood/fire damage too. Check overall condition. Yes, interiors can be easily slicked up and detailed, but generally speaking, a clean interior is a pretty good indicator of overall maintenance.


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