Let’s Talk Motor Oil, Part 1

Have you ever said you’ll do something and then realize the sheer magnitude of the situation? In my last blog I stated that “we’d talk about motor oil”. Well all I can tell you is that this will be quite a feat. It’s like a topic such as “food”. How do you start and where? The sheer size of the topic can make someone nauseous! So, like a discussion about food, we’ll take on this monster topic of motor oil one meal at a time.

If you’ve ever stopped and actually looked at all of the choices of motor oils, you would truly be astounded. Most of us are repeat oil shoppers and grab at the “familiar” packaging before we check out. But the next time you’re at your favorite car parts store, actually take a moment and look around at all of the choices. Oil containers in yellow, green, red, black, and silver (come on Car Guys…Can you name the brands?). Oh, I forgot purple and white colors too. So how do we choose the “right oil” for our beloved machines?

Well, usually we go to the little bible given to us that lives in the glove box, yes, the owner’s manual. There is a manufacture’s recommended oil grade/specification right inside. Auto manufacturers make it even easier by often printing on the oil filler cap what oil is called for in the motor. Usually the first level of info needed to make your selection is the oil’s viscosity and the type of oil, conventional or synthetic.

Viscosity is the oil’s flow characteristics when cold and hot. When a car requires a 5W30 oil, this is oil that in cold weather acts like 5 weight oil (the first number in the code) and acts like 30 weight oil when hot. So why is the viscosity important? Perhaps a quick discussion on what a motor oil does in the engine and why it is important is first in order.

Motor oil reduces friction inside the engine and reduces wear that occurs. It also allows for the motor to start easily and keeps engine surfaces clean. Oil cools moving parts and reduces heat buildup. Motor oil traps byproducts of combustion and suspends it away from engine parts. Lastly, oil prevents rust and corrosion. Without the lubrication of oil an engine would seize up with heat. One dead motor! That is why oil is often called the “Life blood of your car”.

So let’s go back to viscosity for a moment. I hope that viscosity actually means something now. On a cold start, the motor oil must be thin enough to quickly flow to all engine parts to prevent wear. As a side note, most engine wear occurs at cold starts! Therefore, the lower the first number, the quicker the oil flows when the outside temperature is near or below freezing. Have you noticed the newest trend in oils? Have you seen 0W20, 0W30, and 40 weights? They’re out there. The 0 rating means they are the class of thinnest cold flowing oils and are often touted as being the most fuel efficient, gas saving oils of the bunch. And don’t forget that second number, 30, 40, 50, and 60. Those are the hot operating temperature numbers. The higher numbers can offer better hot protection but often sacrifice power and fuel economy. Think of the difference between pouring pancake syrup and pouring molasses (back to food). So what’s a person to do when there seems to be so many variables and so many choices? Remember the bible in your glove box?

You car’s manufacturer has given you lots of info and has guided you to just a choice or two. Remember the oil cap? It may not only have the viscosity needed but may recommend an oil manufacturer  like Mobil or Castrol (just to name two). So when in doubt, match the oil with the owner’s manual. But Uncle Vinny, there’s sometimes alternate acceptable viscosities? It says that I can use a 5W30 as an alternate to 5W20.

I told you this wasn’t gonna be easy! I’ll continue my discussion on motor oil in Part 2. I’ll talk about API seals, ACEA ratings, and auto manufacturer’s requirements when it comes to oils.We’ll also talk a little about conventional and sythetic oils.   Hope you learned something.

Thanks for stoppin’ by.

Keep safe out there!!

Uncle Vinny