In the Spring 2009 issue of Drive, part one  discussed several vehicle components and systems for which regularly scheduled maintenance is recommended. Part two presents additional recommended maintenance items to consider for for the health and well-being of your vehicle.

by Megan M. Pitko

Recommended Scheduled Maintenance

Depending on the year and model of your vehicle and the driving conditions of your area, please follow your Subaru dealer's recommendations regarding scheduled maintenance for these items.

 Camshaft Drive Belt (Timing Belt)

Function: The camshaft drive belt is a flat-toothed belt made of reinforced rubber that drives the camshaft, water pump, and oil pump from the crankshaft pulley of an overhead-cam engine.

Why Inspect: Over time, the cam belt deteriorates from engine heat and normal wear. If not replaced at the proper maintenance interval, the belt can break, causing extensive internal engine damage.

Benefits of Maintenance: Replacing the belt at proper intervals helps to ensure engine reliability for thousands of miles.


Drive Belt (V-Belt)

Function: The belt transfers the engine's rotation by way of the crankshaft pulley to drive the various devices such as the alternator, air conditioning compressor, and power-steering pump.

Why Inspect: The drive belt is made of rubber and may crack over time. Road debris also may cause the belt to deteriorate. Without the belt, vehicle systems will fail.

Benefits of Maintenance: The drive belt allows the vehicle's accessory drive components to operate properly and without interruption.

Fuel System

Function: The fuel system is a combination of fuel tank, fuel lines, pump, filter, vapor return lines, fuel injection components, fuel vents, and evaporative emission control devices. The system contains fuel, pumps it to the engine, and helps to prevent emissions.

Why Inspect: Inspect the fuel system for damage from road debris or leaks to maintain fuel efficiency and low emissions.

Benefits of Maintenance: Maintenance of the fuel system contributes to its reliability, cleaner emissions, and improved fuel economy.

Air Cleaner Element

Function: The air cleaner element is the replaceable filter in the intake system that prevents impurities from the air from entering the combustion chamber.

Why Replace: If not replaced, the filter will clog, restricting airflow and the engine's efficiency. Taken to extremes, an obstructed filter can cause extensive engine damage.

Benefits of Maintenance: Clean filters maintain maximum airflow efficiency and improve fuel economy.

Spark Plugs

Function: Spark plugs have two electrodes across which electricity jumps to produce a spark to ignite the air-fuel mixture in a combustion chamber.

Why Replace: Electrodes in spark plugs wear over time, reducing engine efficiency and performance.

Benefits of Maintenance: Replacing spark plugs at regular intervals helps to ensure proper engine operation and improve fuel economy.

Front and Rear Differential Gear Oil

Function: Oil provides a lubricating cushion for all moving parts in the differentials, which transfer the rotation of the driveshaft to the axles.

Why Inspect: Over time and mileage, heat developed by the friction of the gears breaks down the oil properties, and the efficiency is reduced.

Benefits of Maintenance: Maintaining the differential oil prevents the physical wear of the gears and bearings.
Brake Fluid and Lines

Function: A special fluid used in the hydraulic brake system helps to reliably stop or slow the vehicle. Brake fluid flows from the master cylinder to brake calipers and wheel cylinders through the brake lines, which are a system of hoses and metal tubes.

Why Replace Fluid: Moisture diffuses into the brake fluid through brake hoses and rubber seals. When the water content becomes too high, the system loses efficiency, and the fluid will have to be replaced.

Why Inspect Lines: Cracked, dry, corroded, or flaking hoses will allow the fluid to leak out, which will ultimately result in loss of stopping ability.

Benefits of Maintenance: Periodic fluid changes ensure system reliability and driving safety. Clean, non-rusty brake lines help to prevent a sudden loss of power and control of the vehicle.

Automatic Transmission Fluid (ATF)

Function: Automatic transmissions are designed to use a thin viscosity liquid to transfer the rotational movement of the torque converter to the driveshaft.

Why Inspect: Particles from friction plates, gears, and bearings may block lubrication of the transmission.

Benefits of Maintenance: Clean ATF helps to ensure smoother and reliable gear changes and extends the life of the transmission assembly.

Wheel Bearings

Function: The inner and outer bearings at each wheel cushion the contact surface between the wheels and the spindles on which they sit. The bearings are packed with grease to prevent wear from the friction produced by the rotating wheels.

Why Inspect: Grease can deteriorate over time, and the resulting friction can cause the bearings to fail.

Benefits of Maintenance: Properly greased wheel bearings help to ensure that the wheels rotate properly, helping to maintain directional stability and driver control.

Cooling System

Function: Coolant, a water/antifreeze mixture, inhibits rust. It flows through the engine's cooling system to prevent overheating.

Why Inspect: Over time, a combination of acidic corrosion and engine heat break down the coolant's mixture. It collects dirt, which acts as an insulator and restricts coolant circulation.

Benefits of Maintenance: Maintaining the cooling system helps reduce the risk of overheating and damaging the engine.


Parking Brake/Emergency Brake

Function: The parking brake is a hand- or foot-operated brake that prevents vehicle movement by holding stationary the rear wheels or transmission output shaft. The emergency hand brake is also a backup mechanism for the foot brake.

Why Inspect: The parking brake shoes can wear over time or the mechanism can fall out of adjustment.

Benefits of Maintenance: A properly functioning parking brake contributes to parking safety.

Function: The battery stores chemical energy that turns the engine's starter.

Why Inspect: The battery's chemicals can cause acid buildup on its positive and negative terminals. That corrosion can diminish conductivity and prevent the starter from operating.

Benefits of Maintenance: Maintaining the battery contributes to reliable start-ups.


Function: Wiper blades remove rain, snow, and debris from the windshield (and rear window of some models).

Why Inspect: The rubber in the blades can crack, split, tear, or become contaminated with road film or chemicals. They can warp from long exposure to weather. If film causes water to bead up on the glass or if the wiper action creates a hazy, oily film, clean the glass and replace the blades. A clean windshield is essential for good driver vision.

Benefits of Maintenance: Replacing the blades prevents streaks and improves visibility, for improved driving safety.


Tires Air Pressure

Function: The correct tire air pressure helps your tires last longer, improves vehicle handling, and enhances fuel economy. Tires lose pressure daily, especially in cold weather.

Why Inspect: Tires are important for a vehicle's performance and efficiency. Proper pressure ensures the best-possible fuel economy. Look for the correct pressure in your Owner's Manual, tire placard, or on the driver-side door jamb.

Benefits of Maintenance: Tires last longer with proper maintenance and the correct pressure. Recommended pressure also contributes to good fuel economy.

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