Help me build a list of things to check when buying a vehicle

For those of us who want to go in to more detail, plan for the many what ifs, and know the total cost of ownership in the future, I’m starting a list of often overlooked things to check for when buying a used car. Some of it even applies to a new car!

1 A. Check underneath for corrosion or rust. This is an important and complicated check. The paint protects everything from corrosion for a while. There is a wide range of paint quality. Paint can start to fail in as little as 6 years, or it can hold up beyond 20 years. After the paint fails, how much salt exposure there will be, how frequently it is washed off, and the quality of the steel determines how fast it will rust. Vehicles that are brought up from the south that have minimal rust but failed paint will rust out quickly when exposed to road salt.

1 B. Check the rocker panels (door sills) and the bottoms of doors for corrosion treatment. If there are rubber plugs along the bottom then the insides of the rocker panels were probably treated with some coating to prevent rust. Many vehicles have no paint or anything inside the rocker panel cavity. Salt will gradually work its way in there and then corrosion will occur at a much faster rate as moisture gets inside. After 15 years in a road salt area it is common for the bottoms of the rocker panels to be held together by only the paint. Check the insides of the strut towers for rust. If the vehicle has rubber floors instead of carpet, moisture could have gotten trapped under there, so check for rust under there. Also check for rust from the inside if water may have been dripping down inside the vehicle.

1 C. Is it a body on frame vehicle? Check to see how thin the frame is at its thinnest point. The thinner the metal the faster the frame will fail due to rust after the paint fails. Older trucks from the 90s and before typically have thick channel frames that take a long time to rust even after the paint comes off. They also don’t collect water inside. The 2004 F-150 introduced a thin square tube frame. There are already kits available repair the frames on these trucks that have become undrivable after only 15 years due to frame rust.

  1. Remember that vehicle issues and quality tend to go in a cycle. A vehicle maker that has earned a poor reputation after a decade of poor quality will tend to improve their quality, and a manufacturer that made good quality vehicles for a while and earned a good reputation may start putting out vehicles that have issues.
  1. Find out what engine is used in the vehicle and do some research to see if it has any major issues. Some examples are Toyotas that had oil consumption problems, and Ford’s first generation Ecoboost direct injection that had issues with the EGR soot clogging up the intake. If the engine has high miles, do an oil consumption test or oil pressure test to see if it is worn out due to neglected oil changes. If it has lower miles, to where it is less than mid way through its expected life but too soon for damage from neglected oil changes to show up, then try to find maintenance records or try to find out if the seller is honest by whatever means you can. An original owner vehicle will usually be better cared for. A person who did not plan on selling the vehicle is more likely to have properly cared for the vehicle. For instance, a sudden unexpected move, a death in the family, or a vehicle that is being sold because it was in an accident or broke down will be better cared for than a vehicle that is being sold by someone who knew they would be getting rid of it in a few years.

  2. Do the same research with the transmission. For an automatic transmission, city miles are far worse than highway miles. Many people don’t change their transmission fluid, even at the 30k or 60k miles that it is recommended. Even that many miles between servicing is high for all city driving. Take the pan off and see if the magnets are cleaned off and if there is sediment in the bottom of the pan. You can tell how long it has been since the last proper fluid change this way. Try to find out how the previous owner drove. Some people use nearly full throttle every time they pull away from a stop light. Doing that is going to put a lot more wear on the transmission. If you know that the P.O. drives this way, I would consider the transmission to have 1.5 times as many miles on it compared to one driven by an average driver.

  3. Check

  4. Check brake lines and fuel lines for rust. Replaced brake lines can fail again fairly quickly if not done correctly. They are often not routed correctly and end up getting their protective coating rubbed off. Shrink tube can be put over replaced lines to protect them.

  5. Look at how worn down the brakes are. A brake job is fairly easy, but excessive ware on original brakes indicates a lot of city or hard driving, which means transmission wear.

  6. Test the parking brake.

  7. Push the car down to try to bounce it. If the shocks or struts are bad it will be more bouncy.

  8. Check the rubber boots on the rack and pinion and on the CV axles for any cracks that would allow dirt to contaminate them.

  9. Check when the last timing belt and water pump service was done.

  10. Check for proper antifreeze in the coolant. An aluminum engine should not have just water put in it.

  11. Check that the AC, cruise control, blower motor, and climate control work properly.

  12. Check the tires for uneven wear, which would indicate an alignment problem.

  13. Check the fuel tank and fuel filler tube for rust or damage. Check the straps that support the fuel tank.

  14. Check all the lights. The reverse lights, turn signals, head lights, and all brake lights. Check the electrical connector for a trailer if needed.

  15. Some engines have spark plugs that are difficult access. If this is the case, see when the plugs were last changed.

  16. If the windshield was recently replaced with a non OEM one, it will probably crack along the bottom during the next winter when you turn the heat on all the way. They all seem to do this.

  17. Do all the functions of the radio work?

  18. Do the power seats work?

  19. Do all the power windows work?

  20. Are the brakes fully functional? Are they softer than normal? Cheap replacement brake hoses may have been used. It should be possible to cause the wheels to skid on dry pavement. This is an important test. Front wheels should begin to skid before the rear. If the rear skid first, this is a serious safety hazard.

  21. The more worn tires should go in front or on one side. Putting new tires in the front can cause loss of traction in the rear before the front which is a serious safety hazard.

  22. Are the engine mounts bad? With an automatic transmission and front wheel drive, make a somewhat rapid acceleration from a stop. If the vehicle moves forward but then a fraction of a second later makes a small bump or lurch forward again, this could mean that the engine mounts are allowing the engine to rotate too much. When the engine mounts bottom out it causes the second bump forward. Have someone check the engine for rotation while you apply throttle while holding the brakes.

  23. Look for any cracks in rubber parts under the hood, such as the air intake. See what a replacement would cost.

  24. Check the NHTSA and IIHS safety ratings for the car. Keep in mind that the frontal tests are for crashes under 39 MPH and don’t tell you how the car would hold up in a higher speed highway crash. The side impact crash ratings are the most useful. The distance between the driver seat and the front bumper is an important safety factor. Compact cars with a short distance between the front bumper and front passengers lack crush space and therefore can never be as safe. If you plan to have people riding in the rear seats on a regular basis, beware of compact hatch backs that have little distance between the rear of the vehicle and the rear seating. They offer little protection to the rear passengers in a rear end collision.

  25. Does the rear window defroster work?

  26. Does the self check work on all the warning lights? Some could be burned out or intentionally disabled.

  27. Is there excess play in the steering wheel? There is usually a specification for much is allowed. This could mean there is a problem with the rack and pinion which is rare but expensive to fix, or more likely the tie rod ends are worn.

  28. Is the rack and pinion leaking any power steering fluid? This could be an expensive fix. Is oil leaking from between the engine and transmission? This is an expensive repair.

  29. Inspect the exhaust for corrosion and repairs. Modern vehicles use stainless steel for must of the exhaust system. However, repairs and patch work is often done using regular steel, or nice looking aluminized steel that looks nice but doesn’t offer any protection next to the welds. Patches done with non stainless pipes often fail within a few years.

  30. How wide are the bumpers that are under the bumper covers? Many cars have narrow bumpers that offer no protection in a minor parking accident where the corner of the bumper cover is hit. Some cars have bumper covers that are very low to the ground in front. One mishap with a parking barrier can rip the whole front off.

  31. How strong is the lower radiator support? Some are just plastic. If you ever run over something you could get a cracked radiator. Some cars have a metal splash shield connected from the lower radiator support that adds even more protection.

  32. Does it have low profile tires? Unless you really like the style or want to drive a sports car, low profile tires are something that you generally want to avoid. They offer a more bumpy ride, hold less air and have to be filled up more often, are expensive to replace, and hold up poorly to potholes. Having a flat tire and possibly a bent rim is common when hitting a big pothole with low profile tires.

  33. Are the owners manual and other original documents included with the vehicle?

  34. Do you know the radio anti theft code? Disconnect the battery to see if it has one.

  35. Do you have the keyless entry door code?

  36. Do you know how much a replacement key costs? Does it have a sepecial security chip in it?

  37. Does the vehicle have a theft prevention security module in it? Although this is nice to have on a new car, it can become a big problem in a used car if it or a related system ever fails, as special dealer tools may be needed to reprogram replacement electrical modules.

  38. When does the fuel pump typically fail on this type of vehicle? How hard is it to replace?

  39. Does the vehicle have a factory undercoat? If so, this is good! If it was done later on, this could be a very bad thing if it was not done properly. An improperly applied undercoat could trap moisture under it and accelerate corrosion.

  40. Was the hood ever replaced? If so, was it properly painted? Was the hood liner put back on? Were there front and rear seals on the hood that were put back?

  41. Was the license plate blurred out in the ad for the vehicle? This could mean that the seller is flipping it. So it may not really be grandpa’s car that is being sold because he can’t drive anymore.

  42. Don’t be afraid of a major problem like a head gasket or transmission that is known to fail. Consider the cost of the repair and plan to pay that much less. A single major problem does not necessarily mean that the rest of the vehicle will have more problems than usual.

  43. Is the spare tire included?

  44. Avoid all wheel drive unless you really need it. If it is AWD, check to see if there are special considerations such as needing to have all tires replaced at the same time to ensure that all tires are the same diameter.

That’s all I can think of for now. I didn’t include things that obvious, like a headliner that has come unglued. This list is supposed to be for things that get overlooked. Please help by adding some more things!

Is anyone going to read all of that ? Not me.

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I guess just another reason to not try to sell a car yourself. Who would want this kind of inspection in their driveway? And as a consumer, another reason to just buy new instead. Risk averse people should not buy used.

This is the problem. Many people make the decision to make a big purchase like a vehicle or a house on emotion. You’ll spend more time reading about programming your satellite TV receiver than preparing to buy a $10,000 car. But you clearly don’t qualify for this topic as described in the 1st paragraph.

I read it all and the SNOWMAN just pointed out every thing that has been discussed on this forum many times I think he is off his MEDS again. :upside_down_face:

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I just check the condition and level of the fluids, look for evidence of past accidents (overspray, tool marks on fender bolts, differences in shade of paint between panels), look for leaks, look for rust, and look at the condition of the overall vehicle. Then watch the gauges and look for a check engine light during a long test drive. Generally, if a vehicle has a serious issue, it’ll show up on a decent (15 minute) test drive. I’m not buying anything after a once around the block drive. I try not to buy any vehicle that has a known reliability issue or that I’m just totally unfamiliar with. That’s about it for me.

It’s been my experience that if you’re buying a used car from an individual and all of the fluids look good, the interior is well kept, it has good tires, etc., chances are the owner took care of it and it’s probably ok if the test drive checks out. Pretty good chance they didn’t maintain the vehicle if it has bald tires, hasn’t been washed in years, and the interior is all stained and nasty. I’d hate to buy an older used vehicle from a dealership and I probably wouldn’t. They clean it up and put new tires on it and you can’t really tell what you’re getting, although it’s sometimes obvious they’re polishing a turd :stuck_out_tongue_closed_eyes:. Like when they detail the engine bay with that armor all / clear coat spray junk but the oil on the dipstick is black as your soul.


I was driving by a farm and saw my 61 Corvair parked in the weeds. The guy hadn’t really thought of selling it but I got it for about $100. Needed some work but served its purpose. It did stall on me once driving it home but it was only a vacuum leak so no big deal. You cut corners when you are young and broke.

I bought my 67 Buick wagon the same way I guess. Needed it for house building and the girl was selling it after her guy took off and was just trying to make house payments. Paid $250 for it another $350 for engine work, plus tires, etc. Served it’s purpose and sold it 5 years later for about $250.

I think fraudsters may prefer to sell to dealers. I learned about one story where someone got a diesel Ford pickup from a dealer with something like 90k miles on it. It turns out that the previous owner had likely swapped out the cluster and seats from a junked vehicle, and then put the original parts back in before trading it in to the dealer. It must have had more than twice that many miles on it.

In the olden days checking the wear on the brake pedal was one way to guess if the odometer was rolled back. I think brake pedals have improved in quality so this is no longer applicable.

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That’s a good indicator of use. Mileage used to be a big deal because cars didn’t have overdrive, so the amount of engine wear difference between city and highway driving wasn’t as much, and the thing that would usually send a vehicle to the junk yard would be a worn out engine. Today the engine wear difference between city and highway driving is greater, but a properly maintained engine usually won’t wear out before the rest of the vehicle anyway. The rest of the vehicle, especially the transmission and suspension, is worn out more by how many hours it has been on the road instead of how far it has traveled. More wear is done doing an hour of driving at 30 MPH on a bumpy road with stop and go traffic than an hour at 60 MPH on the highway. A 200,000 mile almost all Interstate highway miles vehicle will be in better condition than a 100,000 mile vehicle that was used for city deliveries. The 100,000 mile vehicle would have more hours on it than the 200,000 mile one.

So engine or moving hours is a far better indicator of vehicle wear compared to mileage.

Like I said before, we traded in our 3 year old 58 Chevy wagon with something like 60K plus miles on it. A couple weeks later it ended up on the OK Used car lot at the Chevy dealer with 28,000 miles on it. Looked great. They had repainted the hood that had the normal sand blasting typical of 58 Chevys. Somebody bought it.

Still applies, I think. I looked at a “50k mile” Mustang GT that had both the brake and clutch pedal worn nearly to the metal. Pass!

A different version of “pedal to the metal”.