Volvo 780 Owner's Manual page 52

1989 Volvo 780
Driving economy
Better driving economy may be obtained by thinking ahead, avoiding rapid starts and stops and
adjusting the speed of your vehicle to immediate traffic conditions. Observe the following rules:
Bring the engine to normal operating temperature as soon as possible by driving with a light foot on
the accelerator pedal for the first few minutes of operation. A cold engine uses more fuel and is subject
to increased wear.
Whenever possible, avoid using the car for driving short distances. This does not allow the engine to
reach normal operating temperature.
Drive carefully and avoid rapid acceleration and hard braking.
Do not exceed speed limit.
Avoid carrying unnecessary items (extra load) in the car.
Check tire pressure regularly (check when tires are cold)
Remove snow tires when threat of snow or ice has ended.
Note that roof racks, ski racks, etc., increase air resistance and thereby fuel consumption.
Avoid using automatic transmission kick-down feature unless necessary.
The following "Special Tips" apply to cars with automatic transmission
For steep hills and when driving for prolonged periods at low speeds position 1 should be selected.
Avoid, however, repeated changes since this can cause overheating of the transmission oil. For driving
on mountain roads with long persistent uphill gradients, select position 2.
When negotiating long, steep downhill slopes, position 1 should be selected and position 2 for less
severe inclines, in order to obtain the best possible engine braking effect.
Do not hold the car stationary on an incline by using the accelerator pedal; instead, engage the parking
brake. This prevents unnessary heating of the transmission oil.
When towing, disengage the 4th gear (the indicator light on the instrument panel goes on).
Cooling system
The risk for overheating is greatest, especially in hot weather, when:
Towing a trailer up steep inclines for prolonged periods at full throttle and low engine rpm.
Idling for prolonged periods while the air conditioning system is in operation.
Stopping the engine suddenly after high speed driving (so-called "after-boiling" can occur).
To avoid overheating, the following rules should be followed:
Reduce speed and downshift when towing trailer up long, steep inclines. The risk of overheating can
be reduced by switching off the air conditioning system for a short time.
Do not let the engine idle unnecessarily for prolonged periods.
Do not stop the engine immediately after high-speed driving, but instead, allow the engine to idle for
1/2-1 minute before switching off.
When the risk of overheating is imminent or in the event of overheating, (the temperature gauge goes
repeatedly into, or stays continually in, the red section) the following precautions should be taken:
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