Because import auto manufacturers have been steadily
reducing scheduled maintenance requirements, many import shops have experienced
a reduced number of repairs sold during a routine lube bay visit. Auto
manufacturers have reduced the required number of annual oil change visits by
using the engine’s Powertrain Control Module (PCM) to estimate engine oil life.
If the majority of miles are extended highway driving, the
PCM turns on the “Oil Change” warning light much later than if the majority of
mileage is short-trip, cold-engine driving. Other factors, including vehicle
speed and engine load, also enter into the PCM’s oil change interval
calculation. In any case, the traditionally recommended 3,000-mile oil change
interval is now rapidly becoming part of automotive history.
MODERN ENGINE OILS
While we’re on the subject of the PCM calculating oil change
intervals, it’s important to install engine oil that’s compatible with the
extended oil change requirements programmed into the PCM’s software. In many
cases, the owner’s manual will include a manufacturer-specific oil
specification for that vehicle. Even if the viscosity rating is the same, many
conventional oils simply don’t have base oils and additive packages required to
meet the extended service requirements.
Most European manufacturers have also established quality
thresholds on engine oil to address scuffing, gelling and sludging issues on
specific engine applications. So, in addition to the traditional API, ILSAC and
ACEA ratings, make sure that the engine oil you’re using also meets the
original equipment manufacturer’s requirements.
Last, many standard oil filters will generally clog and
start by-passing dirty oil at 5,000 miles. So make sure that the oil filters
you’re using meet OEM standards, or at least have the capacity to filter oil
for at least 7,500 miles.
Because lubrication intervals are now electronically
calculated, many shops are seeing their customers less frequently. All too
often, that customer disappears into the franchised quick-lube network and
never appears at his independent shop until he experiences a major mechanical
failure. To counter the influence of the quick lubes, many independents have
utilized newsletters and maintenance reminders to stay in closer touch with
their customers. Some independents have also adopted the quick-lube approach of
offering quick service, coupled with a choice of basic- and premium-level “oil
I put “oil changes” in quotes because any qualified
technician or shop owner knows that changing engine oil is only part of any
scheduled maintenance procedure. Instead of selling marginally profitable oil
changes, many shops are now basing their recommendations on the auto
manufacturer’s suggested inspection and maintenance schedule. In any case, I’m
going to add to that list by suggesting inspections that will increase the
overall profitability of the typical import specialist shop.
A visibility inspection includes an inspection of the front
and rear windshield wipers, wiper fluid reservoir levels, washer/wiper motor
functions and windshield glass condition. A quick test of the wiper and washer
functions will usually reveal badly pitted or extremely dirty windshields. If
you market in extremely cold climates, make sure that the wiper fluid is
properly formulated for sub-zero operation.
A second level of visibility inspection would be to check
all exterior and interior lighting functions, including the emergency flashers.
Keep in mind that because exterior lighting is often controlled by one or more
body control modules (BCMs), a scan tool might be the appropriate tool for
diagnosing exterior lighting malfunctions. Lenses should be inspected for
brightness and damage. Headlamp covers should be inspected for weathering and
water leakage. See Photo 1.
Photo 1: Most weathered headlamp covers can be successfully cleaned. Cracked or broken covers should be replaced.
FLUID INSPECTION AND REPLACEMENT
Although auto manufacturers have nearly eliminated all
scheduled fluid replacements, vehicles should still have the axle oil changed
after extended exposure to high water levels encountered on off-road fording or
flood-stage conditions. Automatic transmission fluid change intervals should
also be shortened if the vehicle is used for heavy towing or has been exposed
to flood-stage water.
Most coolants are now long-life or “lifetime” formulations.
Here again, the experience of the shop’s techs comes into play if it encounters
premature cooling system corrosion and other fluid deterioration situations.
Always install a coolant that’s compatible with the manufacturer’s
Brake fluid flushing is recommended by some manufacturers
and can also be justified by using brake fluid test strips or spectrometers to
determine moisture levels. Power steering fluid should also be replaced if it
appears excessively dirty, contaminated or oxidized. Keep in mind that, while
some fluids are suitable for “topping off” fluid levels, they don’t meet
“replacement” specifications. All replacement fluids should meet OE
BELTS AND HOSES
Because modern rubber formulations are far more durable than
in years past, it’s difficult to recommend specific replacement intervals. In
most cases, hoses are still serviceable if they are pliable and not cracked or
swelled at the connections. Because modern EPDM technology has nearly
eliminated cracking in drive belts, the belts should be tested for wear with a
simple tool available from various manufacturers. See Photo 2.
Photo 2: Belt manufacturers supply tools to measure rib wear on EPDM belts. Although this belt isn’t cracked, it failed a wear test.
In some applications, even a minor amount of rib wear can
contribute to a loss of tension and slippage. Timing belts should be replaced
according to the manufacturer’s suggested intervals. If a timing belt
replacement is recommended, accessory drive belts and hoses should be
considered for replacement, especially on high-mileage vehicles.
Because electronic engine controls and permanent-magnet
starters dramatically reduce cranking amperage, a bad battery can survive well
past its normal service life. Unfortunately, a bad battery fails only when the
vehicle owner least expects it. Electronic battery testers can quickly test
battery capacity, starter condition and alternator output. If on-board
electronic interference prevents the use of an electronic tester, the
conventional carbon pile load tester is a good substitute for testing a suspect
In most cases, battery reliability rapidly declines about
four years after installation. In addition, extreme heat and vibration will
dramatically shorten battery life. If nothing else, check the installation date
on the battery and make recommendations based on your own experience. See Photo
Photo 3: Checking the installation date on a battery can lead to a battery sale. This battery is well over six years old and due for replacement.
WHEELS AND TIRES
Because of tire pressure monitoring system (TPMS)
requirements, tire pressure should be adjusted to manufacturer’s
specifications. If the TPMS warning light is illuminated, the vehicle has a
leaking tire or valve stem. Tires should also be visually inspected for
excessive tread wear, cuts, uneven tread wear, excessive weathering and casing
defects. Tires should also be inspected for mismatching sizes and diameters. In
some cases, one or two inches difference in the rolling circumference of the
tire can prematurely wear viscous couplings in all-wheel-drive vehicles and the
drivetrain in four-wheel-drive vehicles. Tire mismatches also might interfere
with correct operation of the vehicle’s anti-lock brakes and stability
controls. Wheels should also be visually inspected for physical damage.
Re-torquing the lug nuts to specification is always recommended. See Photo 4.
Photo 4: Tire inspection can lead to added tire sales. Tread wear should be measured and compared against new tire tread depths.
Most import manufacturers specify undercar inspections in
their maintenance schedules. Visually check for loose bolts, torn axle shaft CV
boots, swollen or leaking steering rack bellows, leaking shock absorbers or
struts, worn rubber bushings, and rusted or damaged exhaust systems.
With the wheels suspended, grasp the tire at the 9 and 3
o’clock positions and alternately turn it right and left. The steering linkage
shouldn’t show any looseness or binding as the wheels are turned. Next, grasp
the tire at the 12 and 6 o’clock positions and attempt to tilt it in and out.
The wheel shouldn’t show any looseness in the bearings or ball joints.
Last, test the suspension for rebound by placing your hands
on the radiator core support or bumper. Placing hands on the hood can dent the
sheet metal. Suspension travel should be smooth and quiet and rebound should
recover in one cycle.
A shop should have the customer’s permission to remove the
wheels for brake inspection. But an alternative strategy is to inspect the
master cylinder reservoir for low fluid level. A low level might indicate excessive
brake pad wear or a system leak. See Photo 5.
Photo 5: Brake fluid level and condition can be an indicator of worn brake pads and leaking wheel cylinders.
If the fluid is opaque, the system should be flushed.
Excessive brake dusting or metallic deposits on spoke wheels often indicate
metal-to-metal contact at the brake pads. In most cases, worn pads can be
detected by using a flashlight to check brake pad wear. Last, check brake pedal
height and firmness. If applying the park brake remedies a low brake pedal, the
ratcheting assembly in the caliper pistons might be seized.
THE POWER OF OBSERVATION
Most of the above procedures are based upon the powers of
observation. Consequently, it’s important to have experienced people manning
the lube bay. One shop I visited years ago, hired two semi-retired mechanics to
service vehicles and perform lube-bay inspections. Those two men kept a
five-bay shop busy with mechanical repair work. See Photo 6.
Photo 6: Refrigerant circulation can be quickly checked by observing the sight glass on this 2002 Toyota Tundra air conditioner drier.