Suggested fluid exchange intervals vary according to OE service schedules, Henmueller said. While suggested motor oil service intervals vary, he said surveys have shown that most consumers get the oil changed every 5,000 miles, regardless of the OE specification. Also, when a fluid is replaced in a vehicle, consumers expect shops to use OE-specified fluids.
To determine oil condition, cars use different types of onboard monitors: optical, capacitive and algorithmic. Henmueller said the optical system is the best.
Suggested service intervals are getting longer in newer model cars, Henmueller said. The suggestion to replace spark plugs every 100,000 miles has become commonplace. “However, those things (spark plugs) don’t always want to come out after 100,000 miles. At that interval, damage and excessive repair costs may be incurred trying to remove seized spark plugs. The customer may be better served if you suggest replacing them at 60,000 miles,” Henmueller said.
While it’s important to be aware of OE maintenance interval, Henmueller said it is not always in the motorist’s best interest to strictly follow all OE intervals. Instead, the shop should try to determine what’s best for the customer based on the questions noted above.
“(Suggested) OE intervals are based on things other than pure science,” he said. He said some OEs intervals may be based on improving a car’s cost of ownership, which may not result in the best interest of a customer looking for 200,000 or more miles of service life from their vehicle.
“It is a good reference point,” but “remember to take the OE intervals with a grain of salt,” he said of OEM recommendations.
He said a shop should be aware of this when discussing maintenance service options with customers.
Coolant can easily be tested for acidity contamination and mixture strength at OE-recommended cooling system inspection levels, Henmueller said.
For many vehicles, poor fuel quality, adverse driving conditions and lack of other maintenance are good reasons to suggest chemical engine decarbonization service every 15,000 miles or 12 months, he said.
For batteries, a shop should always test and determine if a battery meets OEM specifications.
For OEM shocks and struts, MAP suggests considering replacement of these components after 50,000 miles. It’s not to say that these components are already worn out, but their performance has likely degraded measurably, and to the point that their condition is compromising braking, handling and some safety control systems. This suggestion only applies to original equipment hydraulic fluid and low gas-charged shocks and struts, not electronically-controlled units.
Power steering fluid often becomes contaminated during the first 50,000 miles, he said. A one-time replacement of the fluid can help prolong the life of expensive hydraulic steering components. In addition, power steering fluid should be exchanged whenever a system component (pump, hose or rack and pinion) is replaced.
Shops also have to pay attention to federal packaging and labeling requirements for aftermarket products, Henmueller said. He said the National Institute of Standards and Technology (NIST) Uniform Weights and Measures laws stipulate labeling requirements for products sold at retail.
When writing an invoice, Henmueller suggested always using consumer friendly language, not jargon or incomprehensible abbreviations.
“Document full disclosure,” he said, even if something negative is mentioned. Customers can only make informed choices when shops clearly communicate and document all the facts.