When buying a used car, what kind of inspection do you perform?

[Mursilis]

When buying a used car, what sort of inspection do you perform? I'm curious what everyone does when looking at a pre-owned vehicle to make sure it checks out mechanically.

 

[BassBomb]

get the VIN and look it up on carfax or something
I always check the bodylines to see whether they all line up as perfect as possible or if there are scratches in the paint

driving it will give a good idea on how sound it is too

i dont really do any formal tests until i have bought the car however

 

[radioouman]

Usually a carfax report, and then I do a lot of research to know what the potential problems are with that car. I typically use leaks or worn tires as negotiating tools. As long as it drives OK and the title history is OK, I don't hesitate to buy it. I treat it as though the previous owner didn't do any maintenance, so I usually replace the oil and possibly tranmission fluid just after buying it. I'll also check the brakes.

 

[funboy6942]

Bring friend
Start car

Check for smoke at start up out tail pipe, if a Chevy with 305, 350, 400, 454, motor, a puff of smoke and then clear up is normal, for its seeping valve seals when the engine is turned off, not worth pulling the motor apart to fix and have happen again in 20K miles

Wait for it to warm up and get to temp to be sure the electric fan for the radiator works

Pull off oil cap, while running at temp, and check for ANY smoke at all to come out. If it does, the engine is worn out because that is compression getting past the rings into the crank case

Check oil cap for caked on stuff, and shine flashlight into valve cover hole opening looking for any caked on crap, thick and gooey, thats a sign of the motor not getting a regular oil change.

Pull oil dip stick now while its running. Should be clean and sorta clear with a light brown hue to it. If black it has not been changed in a VERY long time, and if foamy, lots of bubble, or milky white, is a sign of condensation from sitting for a long time without changing the oil, but if milky like mayo, thats water getting into the oil, cracked head/block, or head gasket leaking allowing water and oil to mix. Thats VERY bad, and if you can get the car for $50 pass on it, it needs a cleaning, or motor replacement, for even after you fix the leak now you got to worry about rods rusting up, and breaking loose getting in to rod bearing, or main bearing, causing the motor to fail few thousand miles after. Some will run forever though, and some will just self destruct after fixing the leak and flushing out the water oil mix from inside the block.

After you finish all the below tests and shut the car down. Let it sit for about 5 minutes and check the oil level, along with power steering. Check cap on power steering, it may need to be running to check it on some car models.

Pull trans fluid dip stick to make sure it is bright red, not brown. Brown means it has not been changed in a long time, all the gunk built up on the seals and valve body will come off and the trans is sure to fail if you change it. If its brown, leave it alone, do not change it unless you plan on doing a trans over haul in 20-3k miles. I know 85-95 dodges will blow a trans if you change it when its brown, most right away, so if you own a dodge product be sure to have your trans fluid every 30k, or whats in the manual, and if you decide to skip it, NEVER change it after. OH also check for anything shiny in the fluid, or gritty. Puring some sand in a slipping trans will work for a few mile, and if you see shiny silver bits, thats the clutches coming apart or valve body, it will need a trans VERY soon. Also check its level now thats it is hot and be sure its where it needs to be. If low, its going somewhere for its a sealed system except at the dipstick.

Also some cars a re completely sealed up with the trans, no having to change the fluid, internal filter you cant get to, may not even have a dipstick. I personally do not car for that set up, I like to know when there is a problem so I can fix it and not be in the middle of know where when it decides to blow up with no warning because its completely sealed up. I know some Chevy models are like this, the Malibu is one.

Now thats its been running this whole time get to the back of car near exhaust, have friend gun the motor a few times looking for Blue-Oil, White-Water, or Black-Carbon smoke.

White and kinda floats around to its gone is water getting in the motor, getting burned up, could be a bad head gasket, cracked head/block, or leaking intake seal. Check the water in the radiator at this time, it will be low or empty, check it when the engine is hot and running, less chance of the watter shooting out at you. You turn the motor off, the pressure will build, and you are sure to get burned. In any case use a beach towel when you open it to catch any spray that may come out, some will come out, and you wont get burned.

If black, there are 2 causes. One, if the car is not run hard at least 2 times a month, I mean put the pedal to the metal and let her fly, it will build carbon inside all the exhaust system parts, including caking on the valves, which at some point the valves will not close all the way, you lose compression and horse power that one time you need it to get yourself out of a jam.

The 2nd, and most common is because most people are car dumb, it needs a tune up, and the black smoke is unburnt fuel. Its the main cause of motors running bad, missing, and the CEL lights to come on.

Blue smoke is oil, opposite of why I mentioned I take the oil cap off and look for smoke, but this time the 3rd ring on the piston(s), oil ring, is failing, allowing oil to slip by and get burned up, or the valve seals are shot allowing oil to get in all the time not just when the motor is shut off. In any case its BAD, VERY BAD, pass on it unless you steal it and want to put in a ton of money and work.

Now get on ground and look for leaks on the motor, trans, undercarriage. Green is rad fluid, can be bad sign, black of clear looking is oil or tranny fluid. If its on the motor, most likely oil, on the trans, trans fluid.

While under have friend move steering wheel slightly side to side looking at tie rods, where the rack is connected to the wheels that makes it turn. There is a joint near the wheel called a tie rod, ball and socket looking thing, like your hip joint. It SHOULDN'T MOVE in any side to side, or up and down movement, if it does the tie rod(s) are bad, and the will need to be replaced, and then aligned. IF you do not check and change these, it can cause vibration felt in the wheel at highway speeds, when braking, and when coming to a stop cause the car to veer off to the left or right, meaning if you come to a stop, and your wheel is not straight because you car was pulling to a side, you got lose front end parts, get it fixed right away. You lose a tie rod, you may lose your life for its what makes your wheels go straight. If it pops apart, one wheel goes which ever way it wants to, and your killing people at 75 mph, and maybe even yourself.

Check tires, mainly front. Worn in the middle of the tread means the tires are big time over inflated. If it is worn on both the inner and outer fo the tir, it is under inflated. If worn out on the otter edge of BOTH tires it means either the tires have not been rotated in a very long time, or that person who owns(ed) is likes to whip around corners and beat the hell out of the car. If only ONE tire is showing some wear on the outer edge, its lose steering parts, like tie rods I mentioned causing it, or wheel bearing. If the tread is "wavy" is a sign of weak struts/shocks and the tire is most likely bouncing up and down when driving down the highway, it mean it will need to be replace, and aligned if it is struts on the front, and even maybe some cars when you replace the rear struts.

If it passes most of these tests time to move the car. Move it OUT of its spot it was parked in and get out and look on the ground looking for leaks, or stains for its a sign of a leak somewhere.

If it all looks good, time to get on it.

DO NOT BE SHY, beat the PISS out of the car, in a safe area. You're checking to make sure the motor doesnt miss under a power load, and that the trans shift solid. If it misses, or sliiiiiides into a gear, the trans is weak, and the motor may need a tune up, or worse.

Also if you see black smoke POUR out the tail pipe it means that car has been babied for a LONG time, it can be a bad thing to buy a car thats gone no where over a period of years, that carbon build up is a bitch, it can cause troubles like the trans when you start to clean it all off when you whomp on it, for in some cases the carbon IS whats holding the motor together, and causing it to run like crap.

After a hard driving, stop right away, pop the hood, check for water leaks, for after that beating it just took you will build up massive pressure in the cooling system, and if there should be a external leak thats going to show itself, thats how to find it, quickly, without paying to have a mechanic find it.

Now get back in car and drive normal, as you would, and see how it drives. Shaking when stopping, warped rotors, your buying new ones and brake pads. But if all else is good, steering wheel is straight, doesnt pull when you hit the brakes, shifts good under normal driving, motor sounds good, no taping, or knocking at this point, you will hear ticking, thats the injectors, and passes all my other tests, its good to go, the car should last several years.

If driving and going over 40+ and the car shakes, then goes away, then the whole car or just the wheel shakes, and then goes away, and does this all the time, irregularly, its because the person used about 4 cans of fix a flat in their tire, you need to have the tire removed from the rim and have the fix a flat liquid removed , just be sure to tell the tire tech there may be fix a flat in the tire for some of those products are combustible and will blow up the tire if they are smoking when working on it, or the machine tat separates the tire from the rim should cause a spark if steal rims, and people if one can doesnt fix your flat go get it fixed with a plug or patch.

Car fax report IS NOT the only thing you should be looking at, all it tells you is if its been wrecked and how many owners, what I just taught you was looking for wear and tear on the car it may have now, and whats good and whats bad no matter how many miles are on it You do what I wrote up, you saved yourself a few hundred paying someone else to do it, and you know your getting a good, safe, reliable car, should it pass everything I mentioned. If not, get it for a good deal, can negotiate with the seller with the problems you found to get it fixed before you buy it from a dealer, or get the price knocked down if private so you can afford to get it brakes and a tune up, for thats mostly why people get rid of their car. Its running bad, the cel light is on, and they dont want to bother with putting in a $100 tune up but instead go spend $20K on another car

Hope this helps everyone, and I am surprised nothing like this is stickied in the car forum.

 

[Mutilator]

Originally posted by: funboy42
Hope this helps everyone, and I am surprised nothing like this is stickied in the car forum.

After your post, it might be.

 

[bunker]

Nice post funboy, you should copy that, create your own post so it can be stickied and be the first message.

 

[Mursilis]

Originally posted by: funboy42
Bring friend
Start car
<snipped to save space>

Good stuff - thanks!

 

[Maximus96]

very good advice

 

[Crassus]

I'm going to print this and take it with me.

 

[potato28]

Well, I know here you have to get them certified by a dealership before they can be smogged or replated after selling. They do most of what Funboy listed, but skip over some things that might be important.