Original Operating Manual - ROPA Fahrzeug

269
7 Maintenance and Care
Mercedes-Benz information on the coolant (general):
Normally, coolants consist of water and corrosion protection agent / /antifreeze. The
corrosion protection agents / antifreeze (ethylene glycol with corrosion inhibitors) have
the following tasks in the cooling system, among others:
– adequate corrosion and cavitation protection for all components of the cooling
system
– lowering the freezing point (antifreeze).
– increasing the boiling point.
For reasons of corrosion protection, around 50 5% by volume of corrosion protection
agent/antifreeze must be added to the coolant if the outside temperatures to be
expected do not require an even higher concentration. This concentration (50 %
by volume) offers protection against freezing down to approx. -37 °C. A higher
concentration is practical only if outside temperatures are even lower than this. Even at
extremely low outside temperatures, do not use more than 55% by volume of corrosion
protection agent / antifreeze since this achieves maximum antifreeze properties and
an even higher mixing ratio reduces protection against freezing again and impairs heat
dissipation (55 % by volume of antifreeze corresponds to protection against freezing
down to approx.-45 °C). If these coolant instructions are not complied with, corrosion
and damage to the cooling system are inevitable. Adding corrosion protection agent/
antifreeze increases the boiling point. Increased pressure further increases the boiling
point.. Both physical interrelationships are utilized in modern cooling systems –
the maximum coolant temperature is increased without increasing the risk of boiling. The
cooling capacity increases corresponding to the higher temperature level. Only approved
products (MB Sheet 325.0/326.0) offer reliable protection of the cooling system.
Chapter 7
Maintenance and Care