21P-979-K390 Komatsu BELT

This belt’s main job is to connect the engine’s crankshaft to various components like your alternator, power steering pump, air conditioning compressor, and sometimes even the water pump. Basically, it transfers the engine’s rotational power to run those things. It’s a pretty simple idea, but absolutely critical. Think of it as the engine’s lifeline to all these essential systems. Without it, your battery won’t charge (alternator), you won’t be able to steer easily (power steering), you won’t have A/C, and in some cars, the engine could overheat because the water pump won’t work. It's usually a serpentine belt—a single, winding belt that handles everything. Older cars might have a bunch of V – belts, each doing one job, but that’s less common now. A failing drive belt can cause a lot of headaches. It’s one of those parts that acts like a shield, preventing bigger, more expensive problems. You’ll notice if it starts to go—you’ll probably hear a squealing or chirping sound, especially when you first start the car or when you put a load on the engine like turning on the A/C. If it snaps completely, you’ll lose all those functions immediately. It’s a relatively inexpensive part to replace, and doing it proactively can save you from being stranded or causing serious damage to other components. We carry a good selection here and you can also find options at places like Fixparts Online. Ignoring a worn belt is just asking for trouble down the road. Safe driving starts here: Belt (MPN 21P-979-K390) has a 12-month warranty!

About Komatsu

Komatsu provides innovative and reliable machinery solutions designed to withstand the harshest conditions in construction and mining.

Why Choose Komatsu?

• Komatsu parts are built to last, even in the toughest conditions, so you get more work done with fewer repairs. • We make parts specifically for Komatsu equipment, guaranteeing a perfect fit and optimal performance. • Using genuine Komatsu parts helps maintain your machine’s value and protects your investment. • You can rely on our wide network of dealers for fast, convenient access to the parts you need, when you need them. Komatsu delivers excellence, FixParts Online delivers to your door.