Usually people look at the miles on the car and its age to estimate the condition of the car. Of course there should be a physical inspection of the car if you're going to buy the car, but... generally speaking. You look at how many miles it has run, and you look at how many years it's been on the road. But do these two informations tell you enough about the car? I don't think so... For beginning, the age of the car only tells you how old it is, but it doesn't say anything about how many hours it has been used... May be the car usually sits in the garage during the weekdays and it's only used during weekends. If there are two cars, and they both are 10 years old, but one has been used everyday, and the other has been used every other day... the two cars will be quite different in their conditions. And the miles on the car... that's not so sure too because eventhough two cars might have run the same miles, but depending on how they were run, their conditions will be different. If one car was driven in a city environment, and the other was driven in the open road environment, the two will be different... -- So what I'm suggesting is that along of the milage counter, the car should have hour counter to count the number of hours it was running. Similar to fork-lift or heavy duty equipments... they have hour meter... And another important number to know is the fuel consumption. How much fuel has the engine burnt throughout its life? The engine that burnt more fuel will be the engine that is more old. -- Anyway, I just thought these were important.
If you are that meticulous, you should be doing compression and leak tests. Fuel consumption is not as important as oil consumption which should be none. Highway miles vs city driving, age of the PO, other cars they have can indicate driving habits as well.
Mileage and age aren't as important as HOW it was maintained. Did the owner have a lead foot and redline it all the time? Change fluids at the right time? Let the car warm up? Highway cruising or city driving, which is rough on a car. I've seen beat to hell cars at 100k run into all kinds of problems, but my well maintained car with 229k runs perfect thanks to good maintenance.
The rules I've learned to follow even though I have only a little experience on the matter are 1) Bring friend(s), who are knowledgeable about cars. 2) Test EVERYTHING. Personally, I test the electrical first, turn key halfway and test trunk release, stereo, door locks, lights, interior lights, blinkers, WINDOWS, A/C. Some electrical problems cannot be heard with the engine running. Second, turn her over. Check under the hood. Leaks, oil spots, and it should always sound rhythmic. 3) You can tell a lot about a car just by the seller/salesman. 4) It all takes practice, and a willingness to learn....and the more cars you buy, the better you get at it. (Refer to #1...be the friend who goes along, not just as a buyer.)
It all depends on the car. A 10 year old merc will most likely run just as good if not better than most 5 year old american car, so it depends on the car make as well as the usuage but i look at the make first.
Coming from someone who only buys old cars, I have a list of things I look for before I even consider discussing money. First things first, crawl under and check for rust. I check all along the frame, the floorboards, trunk... I went and looked at a cj7 jeep off craigslist that was supposed to be near mint. Pulled up, it looked great right off the bat however I crawled under to double check, I found holes throughout the frame rails. I also pop the radiator cap and check for a mixing of fluids, same with the oil. Pull the dipstick and see if theres any coolant mixed with the oil. Also, get a good look and smell of the oil, if it smells nasty and burnt like, thats an indication that the vehicle runs hot. Always check simple stuff such as age of the owner, how many owners, mileage, wreck history, and whats been done to it. A vehicle with maintenance records will bring higher value than a car that doesn't. If the car is newer than the early 1990's you can check Kelly Blue Book/KBB online for a used car $ estimate. Also check NADA guides for pricing. Lastly, you can run the vin# using carfax, however dont expect every incident to be reported. If the owner thinks that they can fix it them self, they will (at least try to) so that they dont have to start an insurance claim thus raising their rates. Always best to write down what you are going to inspect ahead of time so you dont get distracted and forget something important. Also, drive it and run through all the gears, including reverse. Check all lights and accessories... Also check the title for any liens or possible salvage title/rebuilt salvage which means it was wrecked but was repaired. Good luck car buyers!
Before ever starting the car: 1) I try to get the owner to let me pull a sparkplug. Most Haynes manuals have a section in the front or back titled "Sparkplug Diagnostics." You can learn a lot from the plugs about how the engine is doing. 2) I check all fluids (amount and color/scent). If someone has a vehicle that is low on whatever, I'm probably not interested. Like was said before, if there is oil in the coolant or the reverse, I'm probably not interested. I check the following: - coolant (cold only) - oil (cold and warm) - transmission fluid (cold and warm and post test drive) - brake fluid (cold and post test drive) - power steering fluid (cold and warm) 3) I look under the hood and under the car for leaks paying special attention to the back of the engine (or where it meets the transmission/transaxle). I'm looking for engine oil leaking from the rear main seal (implying a worn engine/worn rings that are allowing blow-by) or transmission fluid seeping past the front tranny seal. Know the difference between the sight/smell of engine oil vs. transmission fluid. I also look at the tires on their back (towards vehicle center) for brake fluid (brakes are an easy fix, but you want to know if there is a problem before you test drive). 4) I look for rust spots/holes/obvious mechanical issues (things underneath that are bent/missing/wrong). 5) Check tire pressure 6) Is the exhaust pipe tip brown inside (it should not be black, black means the engine has been running too rich) Cold start: - I tell the owner that I do not want the vehicle started prior to me arriving. This lets me see how easily it will start and do the previous inspection points without fear of burns. - I allow the car to warm up to operating temp (about 20 mins) Warm start: 1) Switch engine off, wait a minute, switch back on. 2) Check MIL (engine light, pull codes if necessary) 3) Check functionality of accessories 4) Recheck fluids according to list above 5) Check for exhaust leaks along exhaust pipe, cat, and muffler (careful, exhaust components will be hot) 6) Check vehicle exhaust. Is should be clear at this point. Have the vehicle owner punch the gas pedal quickly. There should not be a smell of oil at the tip of the exhaust pipe when this is done. 7) Using a mechanic's stethoscope, listen to each of the bearings of the engine (this is optional for most cars, not optional for Hi-Po anything or a vehicle you suspect of being raced or seeing other "severe duty") Test drive (finally) 1) Acceleration tests: 0-60 (listen for pinging or other weird noises, does vehicle accelerate like expected) && 45-65 (you are testing the ability of the vehicle to quickly downshift in an "interstate highway merge simulation type thing," if this can be done on a hill that is even better, you want the vehicle to be in top gear and have to downshift in response to your stomping on the gas pedal) 2) Braking tests: 30-0 emergency stop (lock 'em down hard, does it stop smoothly? Vibrations or squealing is a warning) && 60-0 emergency stop (do this if the previous test went OK) 3) Your driving pattern. If you normally drive city miles, do a lot of stop and go testing. If your driving is typically on the highway, get it up to highway speeds. Your test drive should not take less that 20-30 minutes as it takes you that long to get "used" to a car. Chuck Yeager did not just fly those planes around the block... get out there and test 4) Test wrap-up: check the fluids that are listed in the first section and have a "post test drive" note Finale - Walk away: never buy a car (no matter how good of a deal it seems) on the 1st day. Always sleep on it. - Do not form an emotional attachment to the car until $ has changed hands. You are looking for reasons to disqualify the purchase, you are not trying to fall in love. Good luck all, - MORT -
