The first point is that an increasing array of products is necessary for the maintenance and repair of cars and light trucks on United States roads. From the lubricant standpoint, this is really telling. We are currently looking at the need for fast oil change outlets to carry a number of different products, such as API SN and SN-Resource Conserving (ILSAC GF-5) oils, in addition to the companion pair of API SN Plus and SN Plus-RC. Right alongside that are oils meeting General Motors Dexos1 Gen2 specification. And thats just the most current categories!

I also hasten to mention that covering the SAE viscosities necessary for different passenger cars is a growing challenge. For the more-or-less standard API categories, you can choose from SAE 5W-20, SAE 0W-20, SAE 5W-30, SAE 0W-30 and SAE 10W-30. However, there is now a small but real need for SAE 0W-16. What would you choose to stock for your customers?

Engine oils are easy compared to transmission fluids. There are somewhere in the neighborhood of 100 active transmission fluid specifications, and the transmission folks are a lot more strict on the use of their recommended fluids. Thats a point to ponder, since a modern transmission is at least as costly to replace as an engine.

The situation with heavy-duty engine oils is slightly better, since SAE 15W-40 is the big dog on the block. However, SAE 10W-30 has a bit of a split personality. For API CK-4, SAE 10W-30 has a minimum high-temperature high-shear viscosity of 3.5 centipoise, while the FA-4 version has a HTHS viscosity range of 2.9 to 3.2 cP.

In his second point, Jim noted that there are three forces driving aftermarket parts proliferation: foreign nameplates, vehicle age and vehicle technology. At present, foreign vehicles arent a major driver for engine oils since most are content using API category engine oils.

Vehicle age is always an issue. The current average age of a car or light-duty truck in the U.S. is pushing 12 years. My venerable 2008 Nissan Quest is still rolling along at 142,000 miles and is doing great. I have used SAE 5W-30 throughout its life and have had no issues. There are some high-mileage engine oils out there (for cars with 75,000 miles and up) that meet current API standards and have some additional boosts in oxidation resistance and seal swell control as well as wear protection.

There is a real inventory problem with the number of required transmission fluids due to the age of vehicles. Transmissions that are 12 years and older may require a fluid that is currently obsolete but obviously still needed. So-called multipurpose fluids and boosters for current fluids are out there, but have been questioned as to their suitability for use. Another What would you choose? question to consider.

The complexity of modern vehicles is an additional issue. Everything from gasoline-fueled and turbo­charged direct-injection engines to stop/start technology has added to the fun. Lets not leave out diesel engines here. A growing number of vehicles have emissions control systems that restrict the additive chemistry that can be used in engine oils. With this diversity of vehicles on the road, its no wonder that original equipment manufacturers, distributors and installers must carry and handle multiple products in order to maintain light-duty vehicles.

No one benefits from the proliferation of lubricants in the marketplace. In fact, one of the big problems for installers is which products they should stock. For that, its important to know the customer base. If possible, keep track of what kinds of vehicles come to you for service. If there are lots of GM vehicles, perhaps stocking some Dexos1 products would be a good idea. The cost of Dexos1 is rather high, however, so maybe only those GM vehicles under warranty should be considered.

Another issue is what type of fuel is being used. If its diesel, API CK-4 would be a good choice. While SAE 15W-40 is the most common grade in use, SAE 10W-30 offers some fuel economy benefits. Its tough to quantify how much, but well-controlled field tests seem to indicate about 1 to 1.5 percent. Thats not a big deal for one pickup truck, but a fleet might see some real benefits.

One type of vehicle that I didnt single out is hybrids. Engine oil recommendations for these vehicles dont differ from internal combustion engines. The issue here is the possible need for electric motor lubrication.

Pure electric vehicles are another kettle of fish. Thats where you go to the owners manual and use the recommended fluid for whichever application. Teslas maintenance recommendation is quite interesting with regard to what isnt checked.

Unlike gasoline cars, Tesla vehicles require no traditional oil changes, fuel filter, spark plug replacements, or emission checks. As an electric vehicle, even brake pad replacements are rare because regenerative braking returns energy to the battery, significantly reducing wear on brakes, reads the maintenance plan for the Tesla S and Tesla X models on the companys website. Im pretty sure that some of the more uncommon areas such as door locks and hinges do need to be lubricated. No big volume here, but very important nonetheless. At least these are easy to store since they come mostly in four-ounce tubes.

Transmission fluids are another serious issue. Most shops dont plan to carry too many transmission fluids. With nearly 100 different requirements, the odds are you wont have what is needed on a particular day. This calls for scheduling an appointment for transmission work and getting the proper transmission fluid from a dealer or distributor that handles such products.

From earlier conversations and meetings Ive attended, I know that buying fluids from a dealer can be a shock to the wallet! But before you decide to use a multipurpose fluid or an additive booster, ask yourself if the vehicle is still under warranty. If it is, best to use the approved product. If its out of warranty and the customer wants to minimize costs, you might consider one of these products. However, it could really mess up a transmission. Remember, transmissions are now the single most-costly assembly in a light-duty vehicle, so be sure its okay with the customer.

Im going to steal a page from Jim on this and try to suggest the takeaways from the information Ive shared:

The proliferation of engine oil and transmission lubricants specifications. This is a sign of the times, I suppose, but it isnt going to get any easier. I expect that other OEMs may follow GMs lead in creating their own specs.

The proliferation of new viscosity grades. In addition to the traditional grades (SAE 5W-30, for example), we now have SAE 0W-16, and there is work underway in Japan on an SAE 0W-8.

The growth of foreign nameplates in the market. According to Automotive News, there are more foreign vehicles being sold in North America than domestic ones. All you need to do is look at what car is next to yours on the highway to confirm this.

Vehicles are being kept in service longer. The average age of a light-duty vehicle is about 12 years. Heavy-duty vehicles are around 15 years old. Older means more maintenance and more options for lubrication.

Vehicles are a lot more complex. New fuel delivery systems, new engine designs, smaller displacement but higher power output are all a part of the equation. With complexity comes diversity of products.

One item I didnt discuss here, but have in the past, is the need for an improved system of engine oil approvals. Backwards compatibility, in my mind, creates a product that may be a significant compromise in cost versus performance. A better system needs to be found to meet the future needs of the internal combustion engine without breaking the bank.

Electric vehicles may eventually eliminate the need for passenger car engine oils, but that will be years from now. With many cars lasting 12-15 years these days, there will be a need for engine oils for a long time yet. In the meantime, its business as usual (sort of.)

Industry consultant Steve Swedberg has over 40 years experience in lubricants, most notably with Pennzoil and Chevron Oronite. He is a longtime member of the American Chemical Society, ASTM International and SAE International, where he was chairman of Technical Committee 1 on automotive engine oils. He can be reached at steveswedberg@cox.net.