1981 Volvo DL, GL and GLT
The belt tension can be checked by depressing the fan belt at a point midway between the alternator and
fan pulleys as illustrated. It should be possible to press down the belt about 1/4" - 3/8" (5-10 mm). This
also applies to other drive belts on the engine.
pg. 54 Servicing
I 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.
The valve clearance should be checked every 30,000 miles (50,000 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.
Camshaft drive belt
The camshaft drive belt tensioner should be adjusted at the 600-1,200 mile inspection.
An incorrectly tensioned drive belt will impair exhaust emission as the valves will open and close
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