The Extended Oil Change Conundrum: What To Tell Your Customers

Jobbers field a wide variety of auto-related questions from customers on a daily basis and many can really test their mettle, but one issue that comes up more frequently of late is the question of extended oil change intervals. What is the appropriate time/mileage interval, and how can customers best determine their particular needs? This debate is ongoing with supporters on both sides of the fence, so Jobber News spoke with two industry experts – Z. George Zhang, technical director, Valvoline Technical International, and Blaine Sheerwood, chemical technologist, Irving Blending & Packaging – to shed some light on the dynamics of extended oil change intervals.
1. Are extended oil change intervals good for engines?
Zhang: There are several factors to consider when determining a vehicle’s oil change interval. Engine and vehicle manufacturers have gone through thorough design, simulation testing, and extensive field testing to set oil performance requirements and recommended oil change intervals. At Valvoline, we recommend that consumers consider the age of their vehicle, their driving habits, and the vehicle’s owners’ manual when determining how often to change their vehicle’s oil. Oil change recommendations differ depending on driving conditions as well as car make, model, and year. According to car manufacturers, drivers considered “severe” should change their oil more frequently or at shorter mileage intervals than drivers considered “normal.” When you [perform] severe driving, you need to change your oil more frequently. Over half of all drivers are considered severe drivers. According to owners’ manuals, severe drivers are those who drive in one of the following conditions in a typical week:
• In extensive idling or in stop-and-go traffic.
• In cold weather, less than minus 12 degrees Celsius.
• In extreme heat, more than 32 degrees Celsius.
• In extreme humidity.
• Repeated short-distance trips of less than eight kilometres.
• Towing a trailer or using a car-top carrier.
OEMs may allow and approve extended oil drain intervals for fleet vehicles only if careful testing and detailed used oil analysis have been carried out and the fleet has a demonstrated maintenance program.
Sheerwood: Many oil manufacturers make claims that their oil can be used for extended drains. This is a very touchy subject, as different drivers will operate their vehicles in varying conditions, some of which will increase the likeliness of certain contaminants that can compromise the oil. The industry-wide recommendation for extended drain interval optimization would be utilizing recommended oils coupled with used oil analysis testing. Oil analysis data is integral to supporting the useful life left in the oil. Even with oil that claims extended drain, an analysis will show definitively when the oil should be changed out. Extended oil changes are fine for engines as long as the used oil data can support this claim.
2. Can extended oil change intervals be used with older vehicles?
Zhang: Typically older vehicles have much shorter recommended oil change intervals than new vehicles. Older engines tend to put more stress on the oil and benefit from lubricants with special ingredients that help fight the four major causes of an engine breakdown: leaks, deposits, sludge, and friction. These ingredients include antioxidants to better prevent oil breakdown and excessive thickening and detergents and dispersants to better prevent sludge and deposits.
Sheerwood: All vehicles can realize the benefits of extended drain intervals; age, in this case, makes no difference. Again, the risk is on the consumer and dependent on driving conditions and environmental contaminants. For example, a new vehicle could have fuel dilution or glycol contamination that, even with extended drain oils, will prematurely reduce the life of the oil.
3. Are all oils suitable for extended oil change interval use?
Zhang: No, all oils are not suitable for extended oil change interval use. If extended drain is recommended by an OEM (check the vehicle’s manual), only products with the approved formulations are suitable for use in that specific vehicle. Typically, the approved formulations are with well-balanced chemistries and base oils.
Sheerwood: No, not all oils are suitable for extended oil change intervals. Only high-quality products will be able to be pushed beyond the regular oil change time frame. For example, synthetic motor oils have different standards for meeting API. The base oil for producing a synthetic product is much more robust in nature; these types of oils make more claims for extended drain than regular conventional products.
4. Why change oil at all?
Zhang: Oil is comprised of two parts: base oils and performance additives. The molecules within base oils tend to be very stable and typically do not change during use. However, the performance additives are used up during the process. For example, the dispersant molecules will be tied up with moisture, dust, carbonaceous combustion by-products, etc., so these contaminants will be finely suspended in the oil instead of forming sludge or abrasive particles. When a person changes a vehicle’s motor oil, they discard the contaminants and used-up additive molecules. A regularly scheduled oil change is one of the best and least expensive ways to increase the life of a car’s engine. A regular oil change means a cleaner engine and that translates to a car performing at its optimal level and minimizing long-term engine repairs.
Sheerwood: Oil change is a necessity as each oil’s specific additive package, which helps an oil do its job, deplete over time. With a combustion cycle the detergent package that is added to oil is grabbing contaminants and at a molecular level holds onto them, encasing them until your next oil change. When oil gets overused, those additives break down and allow these contaminants to attack your engine, resulting in sludge buildup, viscosity breakdown and ultimately resulting in shorter engine life.
5. What happens to the additive package during extended use?
Zhang: Additive packages are used up during extended use. Motor oil will not function as it is designed to if its use is extended.
Sheerwood: During extended use, the additive package continues to deplete just like any other oil; however with higher quality oil, you are getting a more robust additive package engineered to break down at a slower rate. Couple this robust additive with premium base oil and the result is oil that is allowed to deplete to 60% from its initial starting point. With extended drain oils, this point is not reached as quickly as more cost-effective oils.
6. Do extended change intervals help consumers?
Zhang: Initially, extended change intervals may help consumers with better cash flow, or less cash out of pocket. However, it typically will not help them in the long run as possible engine repair costs will far outweigh the price of an oil change. Vehicles benefit from regular preventative maintenance, and we recommend consumers refer to their owner’s manual on the recommended oil change interval by their vehicle’s manufacturer (and also review their driving conditions to determine if they are a “severe” driver).
Sheerwood: Extended change intervals, used with Oil Analysis Testing, can save the customer money by getting more use out of the oil before the oil has to be changed. Used oil sampling can also help consumers in several other ways as well. Used oil can be tested for several other contaminants that would come directly from the engine and are picked up and protected by the oil. These engine contaminants can inform a consumer of mild or significant issues that are arising within their engine. For vehicles that are coming up on warranty, used oil sampling can allow repairs to
be fixed before the warranty expires.
7. Do extended change intervals help the environment?
Zhang: This question continues to be debated. Extended change intervals reduce the amount of used oil being disposed. However, Valvoline has found that engine age, oil age, and drain interval influence emissions and fuel efficiency. Valvoline conducted an extensive field study on extended drain and reported the findings in a SAE paper (2001-01-3545). Valvoline’s findings included:
• Higher mileage on the engine increases emissions and increases fuel consumption.
• Higher mileage on the oil increases emissions and increases fuel consumption.
• Engines that run at higher drain intervals exhibit greater increases in emissions and fuel consumption – in effect behaving like engines with higher mileage.
Sheerwood: Yes, extended change intervals help the environment because less waste oil is being created due to the consumer needing fewer oil changes throughout the year, and from the higher quality oil burning cleaner.
So what’s the likelihood that there will ever be a fill-for-life motor oil? Experts say close to zero. The main reason is that motor oil does a lot more than lubricate. It also helps to control the engine temperature and clean the engine. In fact, cleaning engine components every time the engine fires is an extremely important function of motor oil. Unlike the transmission, the engine doesn’t operate in a closed system. It deals with outside elements (notably water, dust, dirt, pollen, and engine exhaust) that find their way through the intake and combustion chambers.
Every oil has its limit.