• A car engine's parts need to be tested and diagnosed before a mechanic makes repairs.engine with air cooling image by terex from Fotolia.com
  
  Auto mechanics who need to diagnose a car's problems with an automatic transmission, carburetor, ignition system or fuel injectors needs to purchase the proper automotive testing tools to figure out what exactly is causing a car to run incorrectly. These testing tools can be hooked up to a car's engine via an electrical cable while the automobile is running so that the mechanic can diagnose a car's problems in an exact manner.
  
  

Radiator pressure tester kit

• Designed to diagnose an automobile's radiator for leaks and its ability to withstand both high and low outside temperatures, the radiator pressure tester kit features a long pneumatic tube, temperature gauge and various radiator lids. These lids will outfit most any domestic or import car and will allow the car mechanic to push the pneumatic tube down into any car's radiator during the test. While the mechanic turns the knob located on the gauge control to push a concentrated amount of air into the radiator, the gauge indicates whether any air is lost due to a leak or structural damage.
  
  

IAC signal tester

• Used for diagnosing electronic control module signals that provide the proper direction to the idle air-control motor on port fuel injection systems, the IAC signal tester can be used on a variety of GM and Ford cars. This automotive testing tool features a noid light on its exterior gauge that flashes one time when a signal is sent to it indicating that the injector or fuel system is causing the car's problem, not the electrical system. When this testing tool is used and the noid light does not flash, the mechanic then knows to check the car's electrical system to diagnose the problem.
  
  

In-line ignition spark tester

• Designed to test an automobile's ignition for spark condition so that the car can start without fail, the in-line ignition spark tester contains a rubber handle outfitted with a long metal needle that fits over a car's electrical ignition. When the car's engine is shut off, the auto mechanic inserts the metal end of the tester into the car's main spark plug wire. The engine is then started and the light bulb on the testing tool will flash if the ignition circuit is complete. If the bulb does not flash, the mechanic then knows that he must repair the spark plug itself or take the car's ignition system apart to find out why the ignition is not working.
  
  

Battery load tester

• Since it is very important for a car's battery to be completely charged and ready to start a car's engine, the battery load tester insures that an automobile's battery capacity is full. This automobile testing tool is comprised of a small metal box outfitted with two small cables on either side of the box that are fitted on top of a car's battery while the auto is not running. The mechanic then switches the battery load tester on and reads the gauge that is featured on the metal box to see how much power the car battery is outputting. If the voltage indicated on the gauge is too low, the mechanic knows to either repair the battery's cables or whether to replace the battery altogether.