Over time normal usage eventually causes a motor vehicle's efficiency to decrease in response to engine buildup, aging mechanical fluids and old components. A tuneup is a replacement of the Passat's parts which wear relatively quickly compared to the life of the engine. These items generally include parts involved with combustion, fuel and lubrication systems. Their replacement extends the life of the vehicle by reducing accumulative wear on engine components. Tuneups are generally considered preventative vehicle maintenance.
Remove the old spark plugs using a socket set, then replace them with new spark plugs. It is important to always coat the new spark plug threads in anti-seize compound to avoid stuck plugs during subsequent removal in the future. Torque the spark plugs down to manufacturer specifications using your Passat's repair manual.
Replace the spark plug wires from the distributor to the spark plugs. Ensure the wires are fully seated on the spark plugs by listening for a click. This indicates the connectors are fully installed. Seat the wires on any guide looms present in the engine to prevent them from coming in contact with hot components.
Drain the transmission fluid and use a catch pan to collect the transmission fluid. If the transmission is an automatic, replace the transmission filter first, then the transmission pan gasket. Finally, replace the transmission pan and refill the transmission with the correct fluid type as indicated by the repair manual. Manual transmissions can be drained using the drain plug and filled up using the filler plug.
Drain the oil from the engine into a catch pan by removing the oil drain plug. Replace the drain plug and change the oil filter. Fill the engine up using the recommended oil as specified by the repair manual. Check the oil dipstick with the engine off as you fill it up until the dipstick reads full. Run the car for one minute, then turn it off, check the oil level again and top off as necessary until the dipstick reads full.
Clean the injection system by running an injector cleaner through the gas tank. Wait until the car has less than a quarter tank left, then add the appropriate amount injector cleaner for the tank size as specified by the repair manual. Fill the tank up and continue normal driving to help clean the injectors. This mixes the fuel and injector cleaner to maximize injector cleaning.
Replace the fuel filter, paying close attention to reinstall the new fuel filter the same direction the old fuel filter was removed. Filter locations vary, but the location for each particular year Passat can be found in the repair manual. Once reinstalled, prime the car's fuel system by turning the car to the on position for three seconds and back to the off position. Do not turn the car over until after priming it three times.
Change the car's air filter located inside the air intake box. This is usually located on the passenger side of the engine compartment, but can be located on either side. Once the old air filter is removed, wipe down the interior of the air intake box with a damp rag, allow to dry and install the new air filter. If the car is fitted with an intake cone, replace the entire cone.
