Cooling System Drain and Refill
Draining, Pouring in Coolant - Anti Freeze Protection Table
Model 140 Shown:
A. Drain plug, 1st version
B. Drain plug, 2nd version
Preparation:
- Bottom engine compartment panel removed.
Procedure:
- Except Model 210: turn filler cap (1) anticlockwise as far as 1st detent to release pressure,
- Model 210: turn 2-stage cap half a turn to release pressure.
WARNING: Cap (1) must not be opened unless coolant temperature is below 90°C. Risk of scalding.
- Remove cap (1) after pressure is relieved.
Draining Coolant At Radiator
- Fit hose (12 mm inner dia.) onto the connection (arrow).
- Open drain plug (14), close.
- Drain coolant into a suitable vessel (about 6 liters).
Draining Coolant At Crankcase
1st Version:
- Unscrew drain plugs (4) with seals (5) next to left and right engine carriers, screw on.
Tighten to: 30 Nm.
- Drain coolant into a suitable vessel (metal tray).
2nd Version:
- Slacken drain plug (6) (banjo bolt) next to left and right engine carriers.
Tighten to: 10 Nm.
Refer to NOTE at end of procedures.
- Fit hose (16 mm inner dia.) onto drain plug (6).
- Open drain plug (6) and drain coolant into a suitable vessel.
Pouring In Coolant, Bleeding Auxiliary Heater
- Model 124: pour coolant in up to the marking on expansion reservoir (2).
- Models 129, 140: pour coolant in up to separation level between top part of expansion reservoir (black) and bottom part of reservoir (transparent).
NOTE:
- On Model 129: if expansion reservoir (2) does not have additional ventilation line, (refer to Coolant Overflow Reservoir) detach ventilation line at expansion reservoir (2), pour in coolant, fit on ventilation line and add coolant up to the brim (arrow).
- Model 210: pour coolant in up to marking (cast lug, visible when cap open) on bottom of expansion reservoir.
- Switch heater on.
- Warm up engine by running at moderate speed until coolant thermostat opens.
- Vehicles With Auxiliary Heater: bleed auxiliary heater.
- Top up coolant in expansion reservoir.
- Seal filler neck at expansion reservoir (2) above a coolant temperature of approx. 60 - 70°C.
- Check coolant resistance to low temperatures.
- Check cooling system for leaks.
Capacities Capacity Specifications
NOTE:
- Composition of coolant for antifreeze protection down to -37°C: 50 % by volume water 50 % by volume anticorrosion/antifreeze agent.
- Composition of coolant for antifreeze protection down to -45°C: 45% by volume water and 55 % by volume anticorrosion/ antifreeze agent
- A higher concentration is only of some purpose at lower ambient temperatures.
- A concentration of more than 55 % by volume anticorrosion/antifreeze agent reduces the antifreeze protection and impairs the heat dissipation.
Disposing Of Coolants
The anti-corrosion/anti-freeze agents approved in the Mercedes-Benz Specifications for Service Products are biodegradable substances.
Refer to the legal regulations or local wastewater regulations.
Refer to the Environmental Protection Catalog issued by MBVDIPWU for workshops in Germany.
Operational Monitoring Of Coolant
Check the resistance of the coolant to low temperatures before the start of the cold season.
In countries with high ambient temperatures, check the anti-corrosion/antifreeze agent concentration once a year.
The corrosion protection in the coolant is reduced during operation of the vehicle. Such coolants have a sharply corrosive effect.
The maximum permissible period of use of the specified coolant in car engines is 3 years.
If topping up (after loss of coolant) it is essential to ensure an anti-corrosion/antifreeze agent concentration in the coolant of 50 % by volume (anti-freeze protection down to -37°C).
CAUTION:
- Before pouring in fresh coolant, the cooling and heating system must be free of used coolant and of corrosion residues.
- For this reason, clean cooling and heating system.
Anti-corrosion Antifreeze Agent
Anti-corrosion/anti-freeze agent performs the following tasks:
- provides adequate corrosion and cavitation protection for all components,
- provides anti-freeze protection,
- increases the boiling point.
Use only approved anti-corrosion/antifreeze agents (see Mercedes-Benz Specifications for Service Products).
Water
Use water which is clean and not too hard. Drinking water frequently, but not always, fulfills requirements. The contents of dissolved substances in the water may be of importance for the occurrence of corrosion. If the water quality is not known, distilled or fully demineralised water should be used. See Mercedes-Benz Specifications for Service Products for water quality.
CAUTION: Drain plug (6) (2nd version) with fitting taper for drain hose and captive seal must not be used on the crankcase with drain plug (4) (1st version).