944 L4-2479cc 2.5L (1984)
Coolant: All Technical Service Bulletins
Cooling System - Approved Phosphate Free Anti-Freeze
Group
1
Model
4 Cyl. & 8 Cyl.
Part Identifier
1901
Number
9408
August 30, 1994
Subject:
Approved Anti-Freeze
ATTENTION: Service Manager/Service Technician
Models Affected:
924, 944, 968 and 928
Concern:
Use of approved phosphate free anti-freeze in Porsche all aluminum engines.
All full-aluminum water cooled Porsche engines should only use approved, phosphate free anti-freeze. This anti-freeze may be obtained from
Audi/Volkswagen or Mercedes Benz dealers under the brand names "Autobahn" and "Mercedes Benz" respectively. Where available, "Zerex Extreme
450" may also be used.
General Information:
The anti-freeze is not only for freeze/boiling protection, but also protects the cooling system from corrosions. To have a correct corrosion protection
level in the coolant system, anti-freeze must remain in the coolant system year round. Therefore, the concentration of anti-freeze to water should not be
less than 30% by volume.
Mixing:
Different makes of anti-freezes usually mix; however, in some there are great differences in quality. Therefore, the concentration of anti-freeze to water
should not be less than 30% by volume.
Mixing Table
Freeze protection to:
Anti-Freeze
Water
-30°C (-22°F)
45%
55%
-35°C (-31°F)
50%
50%
-40°C (-40°F)
55%
45%
A higher than 55% by volume anti-freeze concentration shoold be avoided, since the heat dissipation ability of the coolant will be reduced.
Coolant Volume:
Type 924
- approx.
7.0 liter
Type 944/968
- approx.
7.8 liter
Type 928
- approx.
16.0 liter
Topping-up of Coolant:
The effectiveness of the anti-freeze in the coolant becomes less after a longer time period of operation. If, due to coolant loss, coolant/anti-freeze must be
added, an approved quality anti-freeze should be used. In this case it need not be the same approved brand.
Coolant Change: