Porsche 928S 1983, Driver Manual

Page: 66 / 110

To guard against corrosion, the mixture
strength of the cooling fluid should not be
altered, so even in warm weather, never top
up the system with just water.
The system should only be topped up with a
mixture of soft water and cooling system
additive. For mixing ratios see the chapter
"Filling capacities".
To avoid damaging the engine, cold fluid
should only be added to a cold engine.
Note: There should seldom be need to top
up this sealed cooling systems. If there is a
considerable fluid loss, it probably means a
leak in the system. This should be checked
immediately by an authorised dealer.
Draining and refilling the cooling system
1. With the engine cool, set the heating le-
ver to "warm" and remove the cap from
the expansion tank.
(On cars with automatic air conditioning,
set temperature slide control to 30°C
(86°F) and switch on the ignition).
2. Remove the drain plug from the radiator,
and catch the fluid.
3. Remove the two drain screws located
left and right in the engine and catch the
fluid.
4. Renew the sealing washers on the drain
plug for the radiator and the two engine
drain screws, and refit.
5. With the engine stationary, refill the sys-
tem as full as possible.
6. Run the engine until it reaches normal
operating temperature, checking the fluid
level constantly. If necessary, top up the
level in the expansion tank to the middle
line.
7. Refit cap to expansion tank.
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