Black Gold, Texas Tea (34-5)

We may not afford much seriousness to a regular oil change, but it’s a critical part of responsible vehicle maintenance.

Oil is pretty amazing stuff. It’s easy for us to take it for granted but, without it, our RVs would never be able to leave the driveway.

Oil performs a multitude of tasks – it lubricates, cools, cleans, seals and protects metal against rust and corrosion. A thin film of oil holds spinning parts away from stationary parts to prevent friction from metal-to-metal contact which could wear away the surface. Oil helps cool the engine by absorbing heat from moving parts and transferring it to the oil cooler in the radiator, where it will be diffused into the surrounding air. The oil splashes on the bottom skirt of the pistons helping transfer the heat, so that the pistons do not expand inside the cylinders. As you drive, small particles of grit enter your engine through the air cleaner where they could grind against any moving parts. Oil washes these bits of metal away and deposits them in the oil filter where they can do no harm.

Proper lubrication reduces friction, helps to increase fuel economy and increases engine life by cushioning moving parts. It helps seal the piston rings and the cylinder walls to maintain compression, and prevents air from coming in contact with the steel parts of the engine that would cause oxidation or rust on the parts.

Oil bottles come with a variety of markings on the label, some of which can be rather confusing. For example, most of us are familiar with the American Petroleum Institute (API) service ratings, but many have no idea what they refer to. API ratings denote oil quality, ranging from SA for the lowest to SJ synthetic oil, for modern engines with turbochargers. Your owner’s manual will suggest the best oil rating to maintain the warranty of your engine. You may use a better quality of oil than your engine is rated for, but never a lower one.

Another confusing marking refers to the oil’s viscosity. The viscosity, or oil weight, is a measure of the oil’s ability to flow. Like most fluids, oil tends to thicken in colder temperatures. Lower numbers like five or 10 indicate an oil that flows easily in cold temperatures, while higher numbers like 20 or 50 indicate a thicker oil that will hold its thickness in higher temperatures. Using an oil that is overly viscous could result in hard starting in cold weather and poor lubrication until the engine warms up. Conversely, an oil that is too thin cannot provide the lubrication that we need as it breaks down, resulting in damage to moving parts.

This is why we use multi-viscosity oils today (expressed by markings such as 5W20 or 10W30). They act like a very thin, easily flowing oil when the engine is cold, and act like a heavier duty oil to provide protection as the engine gets up to operating temperature.
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