Fundamentals of Mechanical Evaluation and Maintenance of Typical Automobiles

Ross Haselhorst (haselhorst.ross@gmail.com)

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  Water leaks into the trunk or interior;
  
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  Door gasket problems resulting in hi-speed wind noise;
  
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  Significant engine oil, transmission oil, coolant leakage;
  
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  Hard starting when engine cold, or in cold weather;
  
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  Rough idling, surging, flat response (usually temperature dependent),
  
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  Transmission shifting problems,
  
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  Intermittent electrical problems,
  
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  Dashboard or other lighting not working (must be checked at night),
  
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  Engine overheating in hot weather, or on longer trips,
  
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  Air conditioner not working,
  
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  Heater fan or deicing heater not working,
  
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  Windshield wipers or washer not working,
  
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  Tape or CD player (if present) not working,
  
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  Parking brake not working.
  
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  Missing tire jack, lug wrench, spare tire, hold-down accessories, owner’s manual.
  

Evaluation items for any car you are considering purchasing -- regardless of whom you are buying from:

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  Flat surface, let go of wheel, car continue in straight line?
  
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  Flat surface, let go of wheel, apply brakes, car continue in straight line?
  
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  Graveled surface, slow speed, lock brakes, examine tire track.
  
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  Smoothness of ride, free of steering wheel wobble, or rhythmic bumping?
  
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  Smoothness of transmission shifting – both increasing/decreasing speed.
  

Stationary evaluation, engine running

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  Turn steering wheel, listen for power steering squeal.
  
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  Apply brake with steady pressure. “Hard” pedal, no pedal drop with time?
  

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  Listen to engine with hood open -- Look for smoke, listen for vacuum hiss in engine compartment.
  
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  Look under car for evidence of oil, antifreeze leak.
  
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  Check automatic transmission fluid level.
  
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  Close off engine exhaust, check for high backpressure.
  
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  Color of engine exhaust gases and interior of tailpipe.
  

Stationary evaluation, engine off.

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  Engine compartment free of oil spray, antifreeze spray?
  
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  Continue to check under car for evidence of oil and antifreeze leakage.
  
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  Evidence of wiring changes?
  
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  Appearance and level of engine oil.
  
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  Appearance and level of automatic transmission oil.
  
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  Level of engine coolant.
  
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  Appearance of engine coolant – (more important for maintenance than for purchasing decision). CAUTION!! VERY HAZARDOUS IF ENGINE HAS BEEN RUNNING RECENTLY.
  
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  Level and appearance of brake fluid.
  
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  Inspection of engine belts and hoses.
  
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  Inspection of air cleaner (not critical for buying purposes).
  
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  Inspection of spark plugs (for maintenance, not purchase evaluation).
  
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  Bounce test on front and rear of car.
  
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  Inspection of tires – wear pattern, inflation pressure, damage.
  
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  Inspection for “dangling” components under the car.
  
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  Inspection of body of car for evidence of accident repair.
  

(Use www.carfax.com to obtain history of the car? there is a charge.)

After purchase of an automobile (especially one that may have had little maintenance), it’s a good idea to….
Change oil and filter.

Change gas filter.

Flush engine coolant system, put in new engine coolant – 50/50 with water.

(If you’re having the above done by a mechanic, have the thermostat changed, too.)

Have brake wear checked.

Have “front end” lubricated.

Have differential oil level checked (if it has one).

Automatic transmission -- Have it adjusted, filter changed.

Manual transmission – have oil level checked.

Have spark plugs changed.

Consider changing spark plug cables, distributor cap, rotor.

Have general engine diagnostic performed.

If indicated, change belts and coolant hoses.

Thoroughly inspect vacuum hoses for deterioration, clean/replace PVC valve

If indicated, change windshield wiper blades.

Clean, tighten battery terminals. Check water level in battery.