Assume you want to buy a car but want it ‘checked out’ first. What exactly do you have checked? how much does it cost on average? is there a package that auto mechanics have where they investigate all the parts of a car that are relavant in a used car and likely to potentially cause problems, and what is it called.
Compression: Ultimate cylinder pressure is the one critical guide to overall engine performance and prior use (or abuse). I’ll be back with some others later.
Suspension.
Safety first.
Walk up to any decent garage and say “Hey, I’m considering buying this here used car. Can you check it out for me?”
They’ll have a check-list, or at least something in mind. It has cost me from $35-45 in the past, and has allowed me to walk away from a Ford Taurus that had SUBSTANTIAL cylinder pressure issues.
Readings from cylinders 1 and 2 were 120, cyliner 3 was 110 and cylinder 4 was at 90.
I highly reccomend doing this for any used car you buy.
After one of my friends have a GMC dealer try to sell him a “New” truck that actually had evidence of frame repairs, I’m almost tempted to tell you to have it done on NEW cars.
Here is a quick tip for helping determine if the vehicle has been in a major accident.
A friend who worked in a body shop explained that the first thing you should do is determine if the vehicle has been in a major accident. To do this, open the hood the then the trunk) and look at the corners of the compartments, where the sub assemblies are joined together. You will see where the metal has been welded via a spot welder if it was welded at the factory. Body shops don’t use spot welders, they typically weld by running beads. Spot welds look like little eight inch indentations on the top of the metal parts, one every 1 to 2 inches. Bead welds look like thick lines along the edge where the parts meet. If you see bead welds you are on notice that the car has suffered major damage that resulted in the frame being re-welding. Don’t but it, even it’s cheap, chances are it will never drive correctly, and might even be dangerous.
If you are not familiar with the welding techniques, have your mechanic show you the difference. This will cause him to look where he might not otherwise have looked.
Ditto what Jonathan Woodall said. If you have a reputable technician you can trust, you don’t have to direct him to anything in particular. If you say, “Check the compression”, they may not look at anything else and you could be looking at a hefty repair bill right out of the gate.
I would not recommend anyone buy a used car without spending the less-than-$50 to have it checked out. Even if the technician finds something wrong, you can still buy the car but you certainly have better negotiating leverage.
Proof that the timing belt has been replaced, if it has one. On some engines, a timing belt breaking can cause serious damage. You need to start looking hard at this if the car has over 70,000 miles or so.
It’s really not feasible to do this via mechanical inspection. Unless the timing belt is quite new or quite old, visual inspection while it’s still installed usually doesn’t yield useful information. And just looking at it involves some disassembly to remove part of the timing belt cover, so it’s not a quick/cheap thing to do.
A more useful, though still not necessarily definitive, inspection of the timing belt can be made by removing it and flexing in backwards for a close look at its teeth. This of course, means doing all the labor to replace the belt, and it’s usually rather silly to not go ahead and put a new belt on it at that point.
The practical method of dealing with the question of whether the timing belt has been replaced is to see the service records. If they’re not available, the choice is to replace the belt or take the risk of its breaking. If it’s an interference engine, where timing belt breakage can result in bent valves (major repair), it’s a potentially very expensive gamble.
Back to the OP, I agree that the most workable is to find a competent repair facility and ask for a “pre-purchase inspection,” “used car inspection,” or whatever they happen to call it. Trying to come up with a comprehensive list of what to check is much more difficult than finding a capable shop that knows what to check.
Here are some things I look at when buying a used car. Some of these will be part of a mechanic’s inspection, others are just to give you a good idea of the condition of the car.
Wheel wells - gives you a rough idea of the overall condition of the car, if they are very rusty then expect a lot of other things to be rusted and not well taken care of
Open up the radiator cap and look for anything that isn’t anti-freeze. Oil indicates that the engine had some major problem, a blow gasket at the least.
Look at the exhaust pipe for signs of oil burning or weird stuff that indicates the engine isn’t running right
Listen carefully to the engine to make sure it sounds smooth and isn’t “missing”
Stand at the back of the car and look straight down the side of it, then repeat for the other side. Pay close attention to the lines of the car and make sure its symmetrical. If the car isn’t symmetrical then there’s a good chance it was in a fairly major accident and the frame may be bent. Even if the frame was straightened out the car will likely never be right (will constantly wear out tires, etc).
Look underneath for signs of damage. If the body was repaired often something underneath will still be bent which can show you where an accident occured.
Open up the hood and look for signs of an oil leak on the engine. New gaskets can also tell you what parts of the engine were recently worked on.
Remove the oil filler or dipstick while the engine is running. If white smoke comes out the piston rings are worn - the more smoke, the greater the wear.
Water dripping out of the exhaust can mean a blown head gasket.
Grab each wheel with both hands and see if there is any lateral play (the same motion you would use if holding the hips of someone dancing the twist - sorry, only way I can think of describing it). If there is play, the wheel bearings need tightening or replacing.
Sorry, one more quick note. If you can find a garage that specialises in that make of car, the mechanics there will know about all the ‘peculiarities’ of that particular type, what its weak spots are and how people try and cover up any typical problems.
I asked a store this ten years ago & he said he would put it on his diagnosis machine for $25.00…
Besides when you get a car in certain states it has to be smogged & the smogger usually puts it on a machine & that tests a few functions also.
My friend just bought at ‘certified used car’ but I have no idea what that means in car dealer speak.
I know, that’s why I said proof of it being replaced, such as an invoice or other documentation showing replacement. I wasn’t saying he should have it torn down and inspected.
Ah, sorry Joey, I was thinking in terms of what one would ask a mechanic to check.
Sorry myself, I should have been more clear in my first post.
Run it by your local police station and have a drug-sniffing dog go over it.
Check its VIN history through AutoCheck or Carfax. That’ll tell you about any accident reports, water damage, police, taxi or rental use, emissions test history (some states), change of ownership, etc. I wouldn’t but any used car without doing that.
I was reading on fatwallet.com about some people who ran their cars into carfax.com & quite a lot of them said the reports were not accurate. e.g. if you don’t report something to the cops, it won’t show up on the carfax report. Others said that things that were reported didn’t show up either. I don’t know how carfax gets it’s data, but I wouldn’t take it as proof that much.
When I bought a car a few months ago, I used Autocheck because it consistently came up with more data on the same car than Carfax did.
Some basic checks that are easy to perform:
Pull out the oil dipstick. Is the oil low? If the seller is not attentive enough to have the car’s oil changed or topped off, you probably don’t want the car. Dab a bit of oil on your thumb and rub it around with your finger. Feel any grit? That might be carbon deposits or metal shavings from an abused engine. Smell the oil on your fingers. Does it have a burnt aroma? This indicates the engine may burning oil due to worn compression rings.
While you’re under the hood, pull the transmission fluid dipstick (if it’s an automatic). Rub a dab of the oil between your fingers. Does it smell burnt? Is the oil a nice cherry red or dark brown? While driving, check for hesitation or lag in the shifting of the transmission. Is the shift linkage firm and tight or loose and rattling? Is acceleration smooth and uninterrupted? Any problems indicate potential issues.
Stay under the hood and examine the belts for fraying. If they show obvious signs of wear they will need to be replaced. This is also a sign that the car may not have been well maintained. Open the radiator or coolant reservoir and look for a colored sheen floating on the liquid’s surface. If there is a rainbow set of colors floating there, oil has leaked into the coolant. This may be due to a cracked head.
Look at the battery. Is it crusted up with dried acid? Are the cables connected to the posts tightly? Loose cables can burn out the alternator. Look for nicks or cracking in the battery cable insulation and other wiring. Replacing a wiring harness can run over one thousand dollars.
If you suspect poor compression, swipe your finger inside the tailpipe’s outlet. Is there black sooty slime on your finger? If so, the car is burning oil. Dry soot is all right, oily soot is bad news.
Look at the tires. Are they low on tread? If so, lower your offer for the vehicle as the tires will need replacing shortly. Scalloping on the tires’ edges can indicate problems with alignment or the steering linkage. Check the spare and examine its condition as well.
To check the alignment, drive the car in a large empty parking lot. Accelerate moderately and relax your grip slightly upon the steering wheel. Brake sharply and see if the car pulls in one direction or the other. This indicates alignment problems that reduce the car’s value. While driving on the freeway, feel for any shimmy or vibration in the steering wheel. Be sure to test the overdrive (if available) while at freeway speeds and make sure it engages properly. While braking, listen and feel with your foot for any grinding or vibration in the braking system All of these are signs of expensive work to come.
Be sure to shift into reverse and rapidly accelerate the car. The vehicle should accelerate smoothly and without hesitation.
Test the headlights, signals and all other lamps including the inside light. Cycle the four-way flasher and look for all the dash lights coming on during starting. This a lamp test so you can tell if any of the idiot lights are burnt out.
Cycle every single power feature such as windows, seats and door locks. Turn on the radio. Are all of the stations tuned to hard rock and head banging music? If so, the owner’s teenager is probably driving the car and beating the crap out of it. This is an old used car salesman trick when estimating the value of a car.
Open and close all of the doors, hood and trunk. Check for ease of operation and proper alignment. A door that does not shut quite right may indicate the car has been in a wreck. If you feel that the body has been worked on, bring a small rubber coated magnet and see if it suddenly will not stick to a panel in areas that have slightly different paint colors or a rippled surface. Some cars have plastic body panels, so this trick does not always work. Check the paint for orange peel, dings and other problems. A new paint job can equal the cost of the car. This is also a good time to look for rust and other damage.
Performing all of these simple checks yourself will help to weed out many candidates before you ever get them near a mechanic. Take the two or three finalists to an honest mechanic and have them do a complete test of the vehicle. It can cost up to $100 per car, but is ultimately worth it.