Cooling System (008-018)
B3.9 and B5.9 Series Engines
Section 8 - Cooling System - Group 08
An incorrect or malfunctioning cap can result in the loss of
coolant and the engine running hot.
Air in the coolant can result in loss of coolant from the
overflow when the aerated coolant is hot. The heated air
expands, increasing the pressure in the system, causing
the cap to open.
Similarly, coolant can be displaced through the overflow if
the head gasket leaks compression gases to the coolant
bricating system can result in the mixing of the fluids if
there is a leak between the systems: head gasket, oil cooler,
etc. (Refer to Section 7-Lubricating Oil System.)
NOTE: Transmission fluid can also leak into the coolant
through radiator bottom tank transmission oil coolers. Re-
fer to the OEM service manual.
Never use water alone for coolant. Damage from cor-
rosion can be the result of using water alone for cool-
NOTE: A 50-percent mixture of antifreeze and water must
be premixed before filling the system. The ability of anti-
freeze to remove heat from the engine is not as good as
water, so pouring antifreeze into the engine first could con-
tribute to an overheated condition before the liquids are