spark plugs replace VOLVO C70 2002 Owners Manual

For proper functioning of the vehicle and its emission control systems, the timing belt and belt tensioner must be
replaced every 105,000 miles (168,000 km). Engine damage will occur if the belt fails.
PCV system
(on turbocharged models)
The nipple in the intake manifold and the filter at the end of the PCV hose in the air cleaner should be inspected and
cleaned at 105,000 miles (168,000 km) and thereafter, again at 150,000 mile (240,000 km) intervals.
Spark plugs
The spark plugs should be replaced every 60,000 miles (96,000 km) under normal driving conditions. City driving or
fast highway driving may necessitate replacement sooner.
Under normal driving conditions, spark plugs require no maintenance between replacement intervals. When installing
new plugs, be sure to use the right type and to tighten them correctly. When changing the plugs, clean the terminals
and rubber seals. Also check that the suppressor connectors are in good condition. Cracked or damaged connectors
should be replaced.
pg. 118 Fuel/emissions systems
Fuel system
The fuel system is allelectronic and is microprocessorcontrolled. It can continually compensate for variation in engine
load, speed and temperature to give the best economy and power. A mass air flow sensor measures the inducted air. In
this way the system can make instantaneous adjustments for changes in air temperature or density, thus always
assuring the best economy with the lowest possible exhaust emissions.
Heated oxygen sensor(s)
This is an emission control system designed to reduce emissions and improve fuel economy. The heated oxygen sensor
monitors the composition of the exhaust gases leaving the engine. The exhaust gas analysis is fed into an electronic
module. This adjusts the airfuel ratio to provide optimum conditions for combustion and efficient reduction of the three
major pollutants (hydrocarbons, carbon monoxide and oxides of nitrogen (NOx) by a threeway catalytic converter.
Crankcase ventilation
Crankcase ventilation
The engine is provided with positive crankcase ventilation which prevents crankcase gases from being released into the
atmosphere. Instead, the crankcase gases are admitted to the intake manifold and cylinders.
ProCarManuals.com