Starter and Alternator Troubles
Published on
February 9, 2022 at 9:00:00 AM PST February 9, 2022 at 9:00:00 AM PSTth, February 9, 2022 at 9:00:00 AM PST
Is It My Starter or Alternator?
The harsh winter climate can negatively affect the performance of vehicles, and often, heavy-duty vehicles have trouble getting their engines up-and-running in the cold. Rotating electric parts, like starters and alternators, may be the reason why. To find out, drivers will need to test the parts (along with the battery) to see which part(s) needs replacement before making long haul trips. Here's what drivers should know.
Starter Diagnosis.
Simply put, if the engine is slow to crank, or not cranking at all, then the starter is most likely the problem. However, a low battery or loose battery connection could also be to blame, so it is wise to test the battery with a voltmeter prior to making assumptions. Most American semi-trucks require 12 volts to get the battery running while European trucks may need 24 volts. To test for a weak starter, hook up the red lead (positive) of the voltmeter with the positive terminals and the black lead (negative) of the voltmeter with the negative terminal. If the starter gear comes out but does not spin well, the starter could be failing. A good starter gear will spin rapidly, as noted through Match Made.
For the driver that needs to jump-start a semi-truck, 15-20-foot-long jumper cables with a 2-gauge thickness are recommended plus a helper vehicle with a 12-volt equivalent battery and a battery charger. And keep in mind that starters typically last 100,000-150,000 miles. When was the last time you replaced your starter?
Alternator Diagnosis
Alternators act like cell phone chargers and provide the juice to the battery. A weak or dead battery is a sure sign of a failing alternator. Other signs of failing alternators include A battery warning light (don't ignore); grinding noises, and an engine slow to crank with clicking noises. Like starters, alternators have a 100,000-150,000-mile lifespan equating to approximately seven years. When was the last time you replaced your alternator? If you shrugged, it could be reason why you are having issues. You'll need that handy voltmeter again to test the battery before the alternator. The reading should be at least 12.6 volts. If it's lower, it's time to replace the battery. For the alternator, grab a friend to help start the engine. The engine should hold 1500 RPMs and read 13.3-14.2 volts (thanks voltmeter reading). If voltage drops, then you have a weak alternator. But there is one final test. With the engine still running, turn on lights. If you see the voltage, drop again, then it is a sign that the alternator needs replacement.
Need a Replacement?
Folks, it's 20 degrees Fahrenheit outside with snow on the ground. This is not the time to have truck troubles. For a warmer, happier, and safer drive, understand the warning signs of failing batteries, starters, and alternators and how to test them. Good luck, truckers, and we'll be here when you are ready for a replacement.
Who Can I Turn to For Parts?
A good source for replacement truck starters and alternators is Match Made . These parts are designed for all types of heavy-duty applications and come complete with two-year warranties. Shop now.
