Volvo 240 Owner's Manual page 86

Volvo 1990 240 Model
pg. 64 Service requirements
Engine Mechanical Components
Torque manifold nuts
The manifold nuts should be torqued at the 600-1,200 mile (1,000-2,000 km) inspection. A loose
manifold could alter air/fuel ratio and cause an increase in emission and/or poor driveability.
Valves
The valve clearance should be checked every 30,000 miles (48,000 km).
Vacuum fittings, hoses and connections
Unstable idle, misfiring or poor emission control is often caused by leaking vacuum hoses or
connections. Check hoses and connections on distributor vacuum unit, EGR valve (where applicable)
and connections on heater control servo systems and hydraulic brake servo.
Exhaust Gas Recirculation (EGR)
This system operates by returning some of the exhaust gases to the engine to be recombusted: since this
lowers the combustion temperature the amount of nitrogen oxides released into the atmosphere is
reduced.
The EGR valve should be cleaned at the 60,000 mile inspection and thereafter cleaned every 25,000
miles (40,000 km).
Timing belt
The timing belt tensioner should be adjusted at the 600-1,200 mile (1,000-2,000 km) inspection.
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