1) Ask for service records. I do all my own work, but I keep the recipts to show that I have done all servicing myself, and to prove it was done.
2) Look for smoke comming out of exhaust when starting or running.
2) Pull the oil filler cap off, and put your hand over it. Your hand should stay neutral, or be sucked down a little. If it feels like there's pressure building up - the engine is very tired (you're getting blowby at the rings).
3) Look for rust / body dammage EVERYWHERE. Pull out a flashlight - get under the vehicle - look for damage.
4) Check the tires - tires are EXPENSIVE. If the tires are almost bald - it can cost you $500 - $1000 (US) or more to replace them.
5) If it's a soft top, check the thing out really well - does it look like it needs replacing?
6) Check the radiator fluid, make shure it's looks clean, and like there's no oil in it.
7) Check the oil - is it at the proper level? Is it a nice oil color (black and clear are okay, murky brown is BAD BAD BAD)
Drive it around, is it overheating? Is the heater working well? Is it drifting on the freeway? Is the bumpsteer okay, or out of control?
9) Does the engine run smoothly, or rough? Does it settle down to normal idle after worming up?
10) How do the breaks feel? Do they bottom out when you stop? Do you need to pump them to get good feel?
11) Shift it through ALL Gears (including 4wd LOW, and lock the front).
12) There's a little hole in the front of the watter pump that lets watter out when it's stressed - does it look like it's clean, or like fluid has been comming out from time to time (will have white chalky residue)
13) Does the engine look clean, or like it's leaking oil (check this before and after test drive).
14) Ask when he last changed out ALL the fluids (diff, transmission, coolant, break fluid etc). Ask for recipts.
15) If the vehicle is due for a service soon (check the handbook) ask if it's been done yet. If not - take it off the price of the car.
You should be able to look at a car, look at the records, and tell if the driver took good care of it or not. If you can't tell - spend a few $$$ and have a mechanic check it out. It's cheaper than changing an engine or transmission down the road.
Keep in mind, if this truck was offroad only, then ALL of it's miles are HARSH offroading miles. Wheeling is hard on any vehicle. 1 mile of offroad is like 2-5 miles of regular use.
