Changing oil was probably the first task most of us completed in our formative years as professional technicians. What once was a simple task (grab the correct oil weight and don’t forget to tighten the drain plug) has now become complicated like just about everything else in this industry. Whether you’re performing advanced diagnostics but still perform general maintenance services like lube/oil/filter (LOFs) or you’re currently a full-time lube tech, you’ll want to read this update on the changes in motor oil and how they affect you and your customers’ engines.
Crash course on oil
Shop owners know that routine maintenance tasks like LOFs allow for bumper-to-bumper inspections. Inspections are the key to nipping your customers’ major problems in the bud (saving them money), as well as the key to discovering more profitable services that need to be performed. If you are like me, you based your oil preference on the American Petroleum Institute (API) letter on the container, viscosity and type (conventional/semi/full synthetic) required for the engine you’re working on.
As far as brand, that might be based on your personal experiences, word of mouth, price, availability and maybe even impacted by which company has the coolest TV ads or race car logos. I even have to admit that before I took a class on motor oil at Automechanika Chicago in 2015, I thought the only thing I needed to know about selecting oil for my own personal late-model GM vehicle was the correct weight and making sure the oil was either full or synthetic blend. After all, that’s what I assumed GM’s Dexos™ was. Boy did I ever get some myths busted in that class.
|The term “High Mileage” (top label) means the oil typically contains esters to swell seals. Meant to be used in engines > 75 K miles, high mileage oils do not have the energy rating of conventional oils. GM Dexos specifications call for a synthetic or semi synthetic oil and a common GM Dexos viscosity is 5W-30. Before author received his ‘crash course’ on oil, a non GM Dexos oil was used several times in his 2013 Malibu 2.4 Ecotec engine. “If it’s full synthetic, the right weight and a good brand it must be as good or better than an oil with the Dexos logo right?" WRONG! This particular oil container’s rear label gives a little more that just the weight and API of the oil. The ACEA acronym is French for European Automobile Manufacturer's Association.|
As it turns out, there are only a small handful of companies who make the base stock for all motor oils. A few more companies make the additive packages, which then determines how the oil performs. The rest is primarily a tiny bit of customizing combined with a lot of marketing. That favorite brand you swear by? Probably not a distinct advantage over another brand. Viscosity, conventional, synthetic, semi-synthetic and API rating are all still relevant, but by far are not the biggest deal breakers when it comes to selecting the correct oil for that modern engine that comes into your shop for service. Selecting the correct oil weight and API rating these days is like selecting tires that are round, black and the correct diameter. It would be an understatement to say we need to know a little more to make the right selection on those tires. The same is true with motor oil. At the end of the very excellent in-depth oil class, I asked the instructor (Kevin McCartney) two simple questions:
- How many different motor oils would a shop need to carry to service most domestic, Asian and European vehicles? He thought for a few seconds and replied “at least 12-15, but preferably closer to 20.”
- How many oils do most shops carry in your estimation? His response? Most have six or fewer.
|A popular misconception among techs is that an ILSAC GF-5 means the oil meets GM Dexos ™ standards. Notice the absence of that GM trademark label “Dexos” ™ (bottom). Dexos does NOT have a specification number GM standards GM-LL-A-025, 4178M and 6094M are the OLD GM oils. They aren’t recommended for 2011 and later GM models – all of which require GM Dexos ™ 1 for gasoline engines and Dexos ™ 2 in GM Diesel engines and some GM gasoline applications in Europe. It takes a close look to see the numeral 1 at the bottom of the green swirl symbol. Some techs may mistake the swirl for a ‘2’. Bifocal time!|
So what’s the difference?
One fact I learned, which seemed a bit provocative at the time, was that one multi-weight 5W-30 oil maybe thicker or thinner than another 5W-30 oil. Really? Yes, really! This has little to do with the brand. It’s mainly about the oil specifications that go beyond the worn-out convention of thought most of us refer to as viscosity. Just consider how different engines are. Smaller in displacement, higher revs, increased temperatures, tighter tolerances, the growing popularity of turbo chargers, and more exotic materials/metallurgy can be a real challenge for lubrication engineers.