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Z31 buyer guide

Points to Remember When Buying a 300ZX

Buying a car can be a stressful experience, whether itís new or used, sports car or family vehicle. There are plenty of things that need to be checked out regardless of what make and model car youíre buying, and then there are the special points to consider when looking for a 300ZX that may point out why that deal of a lifetime is too good to be true. Always do the same things that should be done when buying any car: look for signs of rust, accident damage and bad bodywork, or poor maintenance. If the maintenance records are well kept, it might be wise to try to locate one of the carís previous owners and see why they got rid of it and if it had any unusual issues, anything that might make you think twice about buying the car. This is all homework that should be done when buying any car, however the following are things that should be checked out in particular on the 300ZX: Be sure that the VIN number on the dashboard and the VIN number stamped into the firewall are matching. If not, this should set off a red flag in your head that the car may have been stolen or in some sort of accident.

  1. Know what youíre looking at. Often someone will be selling a car that they believe is, for example, a 1987 when itís really a 1988. When in doubt, check out the VIN. The 10th digit designates the production year.
  2. Always try to get access to the car first thing in the morning before you buy it. That way the engine is completely cooled down and a warmed up engine cannot mask issues like weak batteries and starting problems.
  3. Check underneath the car to see if the front frame rails have been damaged in any way. If they are bent, usually this can indicate some sort of minor accident, such as curb mishaps. It would be best to have a professional take a look at the alignment to make sure that it can still be adjusted to fall within manufacturerís specifications.
  4. If the car has maintenance records, check to see if the timing belt has been changed recently. If not, or if the records donít seem to make sense, plan on changing the timing belt as soon as possible.
  5. Take a look and see if the corrective work was done to the injection system on the car, or if there has been any sort of engine fire. Fire damage would be easy to spot, check for melted insulation on the underside of the hood and also be wary of any melted wires. If the injector work has been done, there should be some components that may look newer, and also the connections to the injectors will be spliced into the wiring harness. If the work has not been done, make plans to have it done as soon as possible.
  6. Check and see if all of the glass in the car is the same. If some pieces are different, it may be an indicator that the car was in an accident or that the window was broken out by vandals or thieves attempting to steal the carís contents or the stereo system.
  7. When you take the car on a test drive, try taking it through a brushless car wash. The high-pressure water jets are useful for detecting leaks, which are common where the door glass and the T-Tops meet the roofline and also around the rear side windows. Sealant around the rear side windows can be replaced by removing the window and replacing the worn-out sealant with new butyl tape.
  8. Rust is most often found in the back of the car at the bottom of the spare tire well, and on the left just above the muffler. If there is rust, take corrective actions as soon as possible before it rusts through. Sometimes it will also show up at the bottom of the firewall and where the rear crossmember mounts. If you see any there walk away.
  9. When test driving the car, take it to a vacant lot where you can put the car through its paces. Accelerate full throttle and check for smoke coming from the rear. Swerve a couple of times and brake sharply. If the wheel shimmies when you brake, be prepared to have a potential issue with a brake rotor, ball joint, steering linkages or alignment issues. If you have a chance to take the wheels off of the car, put two lug nuts on without the wheel and then attempt to forcibly remove the rotor from the car. If the rotor feels loose, then something is amiss and further inspection would be necessary to determine the cause of the problem. If the rotor comes off completely, start looking for another car.
  10. Examine the tread on the carís rear tires. More than likely the tread will be worn much more on the inside edges than the outside, as this is a common problem with the 300ZX, largely due to the excessive negative camber on the rear wheels. If the tires are worn extremely unevenly, be prepared to change the tires on this car often.
  11. Be sure of your reasons for wanting the car. If youíre going for performance, a turbo is a must-have. Turbo swaps can be done, however a great deal of time and money will be spent replacing many non-turbo parts. If youíre thinking about lowering the car and using stiffer springs, be prepared to deal with problems with the rear camber. Lowering a 300ZX can exaggerate already existent issues with the negative camber in the rear end. Motorsport Auto produces a kit that is designed to provide +1 to +1.5 degrees of camber, and most respectable racing shops would install the kit and the springs and align the car for a nominal fee.
  12. Remove the oil filler cap and check the underside of the rocker arm cover for any imperfections or particles suspended in the oil. Black oil does not always mean trouble, just that the oil is in need of changing. It would also be advisable to check the oil filter; a generic filter may indicate that the owner doesnít do his own maintenance and may have cut corners on some parts. Cheap parts now can cause many problems later.
  13. If possible, check out the engine, transmission and differential mounts to see if they have separated. Typically this will not cause a problem, but may result in unusual noises and be something you would have to correct later on, which can be an inconvenience, as the entire rear suspension would need to be removed to replace the bushings.
  14. Another telltale sign of a minor accident can be the condition of the air conditioning condenser. Look under the front bumper towards the radiator. The condenser is just in front of it, and should be flat and straight. If the condenser is warped, it doesnít necessarily mean that it doesnít work; the car may have had a minor accident.
  15. Using a 10mm nutdriver, remove the carís air filter and inspect it carefully. The outside should be reasonably clean, and the engine side should be extremely clean, if not spotless.
  16. Leave the car idling and take a walk behind it to smell the exhaust. Any unusual smells or oddly colored smoke can indicate tuning problems. If it smells of rotten eggs, more than likely the catalytic converter is either worn out or stopped up. Bluish smoke is an indication that oil is being mixed in the cylinder, white smoke can be indicative of coolant (often a head gasket issue), and blackish smoke indicates a rich fuel mixture. Also listen to the engine and note any misfires or partial misfires, as these may indicate worn ignition components.



Sources Used on This Page: Based off of Morgans Buyers guide from Z31.com