Volvo D11F Operator's Manual And Maintenance Instructions page 103

Maintenance and Service 99
Cab Air Filter
Air going into the cab passes a filter located on the right, front side of the cab.
Remove the filter and check it every 19 200 km (12,000 miles). The filter
should not be cleaned and reused. Replace with a new filter as necessary.
Change the filter more often if driving in dusty conditions. A clogged filter
decreases the efficiency of the air conditioning system.
If the vehicle is equipped with a sleeper heater-A/C system, there is a filter for
recirculating air. It is located behind the passenger seat on the bunk support.
The filter should be checked after 19 200 km (12,000 miles), more often in
dusty conditions. Replace the filter as necessary. To inspect or to change the
filter, open the luggage storage lid and pull out the filter.
Paint and Brightwork Care
Cab
When using a pressure washer to clean the vehicle, do not direct the spray at
electrical components in the engine compartment such as the alternator,
starter and compressors. Water spray from pressure washers can damage
electrical components.
Wash all exterior painted surfaces frequently to remove dirt. It is especially
important to wash off salt-laden snow and ice during the cold season. A mild
detergent approved for automotive cleaning can be used but avoid strong
detergents.