Volvo 850 Manual page 80

On long, steep hills, select position 3 or L if the transmission displays
a tendency to hunt between gears.
When driving down long, steep slopes, select position 3 or L. This will
provide the best engine braking power.
Do not attempt to keep the car at a standstill on an uphill slope by
pressing the accelerator; use the brakes instead and avoid the risk of
overheating the transmission oil.
Drive slowly and carefully through deep water (flooded roads).
The engine may be seriously damaged if water enters the air inlets
and reaches electronic components. Do not drive through water deeper
than one foot (30 cm).
Certain turbo models have reduced ground clearance due to the low-
slung design of the chassis, with a risk of scraping against kerbs or
banks of snow.
Extra floormats in front of the driver's seat may catch on the accele-
rator pedal. Ensure that the accelerator pedal is not obstructed.
Cooling system:
The possibility of the cooling system overheating increases, particularly
in hot weather, if:
... you drive at full throttle and low engine speed up steep hills
and with a trailer.
... the car idles with the air conditioning switched on.
... you switch off the engine directly after driving at high speed.
... you mount extra lamps in front of the grille.
Volvo recommends that you do not mount extra lamps in front of the
grille on the 850 Turbo.
To avoid overheating:
Reduce speed if you are towing a trailer up long, steep inclines.
Switch off the air conditioner for a while.
Do not allow the engine to idle unnecessarily.
Do not switch the engine off immediately when you stop after hard
driving.
The engine:
Do not maintain an engine speed of over 4500 rpm if driving in hilly
terrain with a trailer or caravan as this can raise the oil temperature
abnormally.