The PCM Effect on Oil Service – UnderhoodService

The PCM Effect on Oil Service

As with everything else under the automotive sun, technology is changing the lube, oil and filter market. More specifically, modern technology is making it possible to use the vehicle’s on-board engine management system to mathematically determine the length of an oil change interval.

At the most basic level, the PCM simply adds up the mileage since the last oil change and then turns on a light reminding the owner that the oil needs changing. At a more sophisticated level, the PCM can calculate the engine’s average operating temperature, loading and trip length in order to arrive at a recommended oil change interval. Instead of tracking his vehicle’s mileage by comparing it with a traditional lube sticker, the driver merely waits for a PCM-activated reminder light to alert him of the impending need to change the engine oil.

Clearly, if this technology is implemented throughout the major vehicle lines, the net effect will be to eliminate the standard, fixed-mileage oil change in favor of variable, extended length oil change intervals. Since the current practice of sending regular customers an oil change reminder every three months may well become obsolete, the typical independent service shop may find itself developing new tactics, such as mailing a monthly or quarterly newsletter, to keep in touch with its customer base.

Unfortunately, eliminating fixed-mileage intervals may leave the independent shop in a reactive, rather than proactive, stance regarding oil change intervals. When the oil change reminder light does come on, a shop must be fully prepared to use the oil change service as an opportunity to sell other needed services such as timing belt replacements, brake inspections, wheel services and safety inspections.

If the shop misses an opportunity to sell needed maintenance, it may not see the vehicle again until the on-board computer determines the need for another oil change. Worse still, if the customer begins using a stand-alone quick-lube service operation for his oil changes, he may be ignoring critical items covered in the vehicle manufacturer’s original maintenance schedule, such as valve lash adjustments or timing belt replacements.

Traditional “Oil” Service
Throughout the history of the independent service market, the oil change was a small part of a detailed scheduled maintenance plan that included the inspection, adjustment and lubrication of just about every moving part on the vehicle.

Many scheduled maintenance services were performed at recommended intervals. They included:

  • Testing emissions components like oxygen sensors and EGR valves;

  • Inspecting and replacing cam timing and accessory drive belts;

  • Changing air, fuel and oil filters;

  • Adjusting the engine’s intake and exhaust valve clearances;

  • Lubricating linkages;

  • Coating rubber door and hatch moldings with silicone sprays;

  • Checking safety items like lighting and wiper blades;

  • Lubing door locks and hinges, and, of course;

  • Changing engine, braking and drivetrain fluids.

As you might suspect, scheduled maintenance has become a highly profitable service, especially in an era when mechanical and electronic reliability has increased to the point of eliminating vehicle breakdowns during the first 100,000 miles of vehicle operation. Technical Takeover

What conditions determine an oil change interval? As mentioned above, the PCM may calculate an oil change interval by mathematically averaging data such as the engine’s operating temperature, engine loading and trip length. These data are important because the combustion inefficiencies created by a cold engine during short-trip driving will quickly contaminate the engine oil with unburned hydrocarbons and water.

Long-trip, average-load driving, on the other hand, improves combustion efficiency because the engine and engine oil is at operating temperature, which drastically reduces oil contamination and, therefore, lengthens the life of the engine oil.

Conversely, if the engine pulls a heavy load, such as a travel trailer, engine oil temperatures may increase to the point that the oil begins to oxidize and lose its lubricating value. Since oil cooling and filtering capacity on the typical late-model engine are limited due to cost and space, oil change intervals must be shortened to compensate for extreme operating conditions such as short-trip driving or heavy-loading conditions.

Stretching Change Intervals
Many shop operators believe that using fully synthetic or synthetic-blend oils are a valid reason for extending oil change intervals. Going back to the basics, let’s keep in mind that while synthetic oils have a much wider range of heat stability, they can still be heavily contaminated with unburned hydrocarbons, particulates and water just like their more conventional “dinosaur oil” counterparts.

Of course, more than just the oil wears out in an engine. When oil contamination is high, the oil filter often wears out before the oil does. When the filter media becomes clogged, the oil filter safety bypass valve opens and allows unfiltered oil to circulate throughout the engine. In this case, even though the oil itself retains its lubricating value, the oil is rapidly becoming contaminated with abrasive particles that will grind away at precision engine parts.

Remember that even the most optimistic oil change recommendations from synthetic oil producers state that the oil filter should be changed at the OE-recommended intervals to prevent the filter from bypassing dirty oil into the engine’s lubrication system.

Management Strategies
Whether or not to adopt a quick-lube service is becoming an important issue for many independent shops. On one hand, using a dedicated service bay for a quick-lube operation may improve shop efficiency and productivity.

On the other hand, a lube bay technician may begin overlooking valuable scheduled maintenance and repair opportunities in his rush to maintain a high car count through his quick-lube service bay. Also, using repair bay lifts for oil changes inevitably results in scheduling pressures and conflicts that may cause huge losses in shop productivity.

Staffing also becomes a problem because most highly skilled technicians feel that it’s a waste of their time and talent to do oil changes. By the same token, an entry-level technician may miss needed maintenance or repair items because of inexperience and lack of vehicle-specific knowledge.

The ideal quick-lube operation would be a fully equipped drive-on lube pit staffed by older, perhaps semi-retired technicians who can quickly spot needed maintenance and repairs. The ideal quick-lube bay also should have computer access to a vehicle’s service history so the lube technicians can help sell scheduled maintenance and refer needed repairs to the service writer’s desk for dispatch to skilled technicians. In this way, oil changes can be performed quickly and profitably without losing efficiency and productivity in the repair department.

What You’re Really Selling
The final thought in selling modern oil change services is that a shop shouldn’t be selling “just an oil change.” Instead, it should be selling peace of mind to its customers, who should leave knowing their vehicle has been truly inspected and serviced according to OEM specifications. After all, scheduled maintenance has always been the cornerstone of the independent service shop and will continue to be as long as discerning vehicle owners steer away from the dealership.

Avoiding the Bugs in VW Oil Changes
Changing engine oil seems like a simple task, but every manufacturer has a few unique procedures and precautions that are specific to their models. One example is Volkswagen. Before you roll a 1999-2001 VW into your shop for an oil change, there are a couple of important things you should know.

Oil Change Procedure
All 1999-2001 Volkswagens could have an oil leak problem after an engine oil change because of minor contaminants on the threads of the oil drain plug or oil pan. If both are not cleaned prior to installing and the oil drain plug is not tightened to the proper torque, the resulting leak could eventually cause engine damage.

  1. Drain the oil, then clean any contaminants from both the oil drain plug and oil pan threads.

  2. Inspect the drain plug seal for damage. If it’s damaged, replace the drain plug as necessary.

    Note: Never install a drain plug sealing ring from another application. To be on the safe side, always use the manufacturer’s drain plug and sealing washer combination.

  3. Install the oil drain plug and tighten it to the proper specification as listed below.

All models except Euro Van – 22 ft.-lbs. (30 Nm)
Euro Van with 2.4L and 2.5L engines – 37 ft.-lbs. (50 Nm)

Caution! Do not exceed the specified torque. A higher torque may damage the oil pan or bend the sealing washer, which can also lead to leaks at the drain plug.

Do not overfill! Overfilling the engine can cause misfire Diagnostic Trouble Codes to be stored in the Engine Control Module (ECM). You do not want your customer returning with the Check Engine light on right after you changed the oil.

To Prevent Overfilling

Engine Oil Capacity Table

  1. Add approximately 1/2 quart less than capacity (see Engine Oil Capacity table) Note: Capacities shown are for when the oil and oil filter are changed.

  2. Start the engine and let it run until the engine’s operating temperature is approximately 140

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