5W-20 vs 5W-30 vs 10W-30: What’s the Difference?

5W-20 vs 5W-30 vs 10W-30

The primary difference when looking at 5W-20 vs 5W-30 is their viscosity once your engine has reached operating temperature.



How to Test Engine Compression

Test engine compression

Testing engine compression provides a snapshot of the health of your engine. In this video, we show you how to do it and how to interpret the results.



What Happens if I Use the Wrong Weight (Viscosity) of Oil?

It’s best to use the viscosity recommended in your owner’s manual, but a slightly thicker oil or thinner oil likely won’t do lasting harm.



How to Repack Trailer Bearings

Repack trailer bearings

Repack your trailer bearings yearly to ensure your next vacation or trip to the lake goes smoothly. Here’s how to do it.



AMSOIL Helps Awaken 500+ HP Cummins 4BT Engine

Kenny Hauk dynos a Cummins 4BT

We help Kenny Hauk’s crew turn a stock 105-hp Cummins 4BT engine into a 500-hp powerplant for his latest build.



Diesel Engine Oil Specifications: Making Sense of CK-4 & FA-4

Semi truck driving through mountains

The API CK-4 and FA-4 diesel engine oil specifications are designed to help meet tight regulations while providing excellent wear protection.



What’s the Best Heavy-Equipment Grease?

Best heavy-equipment grease

Grease must resist extreme impacts, fight wear, resist water washout and more to be considered the best heavy-equipment grease.



Diesel vs. Gas Engines: What’s the Difference?

Diesel vs gas engine

They burn different types of fuel, but that’s just the start. Here’s what you need to know when comparing diesel vs gas engines.



How to Charge a Car Battery

How to charge a car battery

You can easily charge a car battery with a battery charger or jumper cables in a few minutes. Here’s how to do both.