Heavy Duty

How to Test Glow Plugs

Glow plugs are installed on many diesel engines to help with cold starts. They usually fail because of corrosion, overheating, mechanical damage, or metal fatigue, and their failure can cause a variety of problems. The easiest way to test a glow plug is by using a clamp-meter, though digital multimeters can also do the job, and glow-plug testers also work. We will cover the following topics in this post: What is a Glow Plug? What are the Symptoms of a Failing Glow Plug? How to Test Glow Plugs with a Clamp-Meter How to Test Glow Plugs with a Digital Multimeter How to Test Glow Plugs with a Glow Plug Tester Caution: Be careful to follow the glow plug manufacturer’s precautions when testing, as well as the test tool’s directions/manual, and read the vehicle (or other system) manual before doing any test.

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