1. Conditioning the Vehicle For Cold Weather Operation
The following maintenance and service operations should be performed during a vehicle "winterization":1.1 Engine Maintenance
1.1.1 Valve Clearance
The proper valve clearance will insure that all valves are completely closed during the compression stroke, thus assuring the maximum compression required during starting. Check the workshop manual (microfiche) for the correct adjustment specifications for the various diesel engines.
NOTE:
If the vehicle is operated in areas with ambient temperature below -20°C (-4°F) for extended periods, the valve clearance as specified for the intake valves should be increased by 0.05 mm (0.002").
1.1.2 Injection System
Correct timing of the injection pump, clean and properly adjusted injection nozzles, and tension-free and well-lubricated pump linkages are essential for trouble-free operation. A check for fuel leaks on the low and high pressure fuel Systems should be made.
1.1.3 Fuel System
Check the entire fuel system for dirt and water. Clean fuel tank, hoses and filters if indications of dirt or water are present. Replace fuel filters if required.
1.1.4 Cooling System
Check the condition of the radiator, water hoses, hose clamps and thermostat. The system should be pressure-tested for leaks.
1.1.5 Engine Coolant
Cheek the overall condition and the degree of protection of the engine coolant. Replenish anti-freeze with Mercedes-Benz Anti-freeze/coolant No. 900 583 01 20). To avoid introducing air and calcium deposits into the cooling system when refilling with new tap water/anti-freeze mixture, replacement of coolant (except at scheduled three year intervals) should only be made if absolutely necessary. The amount of anti-freeze in the coolant should never be less than 34% to provide the required corrosion protection.
Be sure to flush the radiator and cooling system before replacing the coolant.
The list shown is a guideline for recommended anti-freeze - water mixtures for various temperature ranges:
A mixture of greater than 50% anti-freeze is not recommended, due to adverse effects on engine cooling.
1.2 Electrical System
1.2.1 Battery and Charging System
To insure ample power for starting, it is essential that the battery be in good condition and at a reasonable state of charge.
NOTE:
Please advise your customers that it is recommended to fully recharge the battery after several repeated cold starts on consecutive days.
Thoroughly check the battery condition: perform a visual check and load test.
Charge the battery to its full capacity. If tests indicate a potential problem, we recommend that the battery be replaced.
All electrical connections should be tight and in good condition to prevent losses through loose or corroded connections.
Check the alternator output and all V-belts for condition and proper tension.
1.2.2 Preglow System
Check the function of the preglow system. Check all electrical connections for tightness and condition.
1.3 Fuels and Lubricants
1.3.1 Winter Diesel Fuel
To prevent clogging of the fuel filters due to paraffin crystallization, only winterized diesel fuels must be used if the ambient temperature is below 0°C (32°F). For detailed information on fuel conditioning, refer to Section 2.2, "Selection of Diesel Fuel-Blending for Winter Operation.
1.3.2 Engine Oil
When it becomes necessary to start the engine in temperatures below 0°C (32°F), engine lubricants of lower viscosity should be used. Figure 1 shows the proper oil viscosities at the corresponding temperatures.
1 SAE 1OW may not be used in OM 617.95 (Turbo Diesel Engine). Use multigrade oils of corresponding viscosity instead.
2 SAE 40 may be used if ambient temperatures constantly exceed 30°C (86°F).
If ambient temperatures are frequently below -10°C (+14°F), the use of SAE 5 W-20 or 5 W-30 engine oil is recommended.
For approved engine oils, refer to the appropriate Service Information under Group 00.
1.4 Starting Aid - Block Heater
Years of experience and tests under extreme conditions have proven that a properly installed engine block heater is the most reliable starting aid, even at extremely low temperatures.
The use of a block heater at temperatures below -18°C (0°F) will assure successful engine starts. One to two hours of block heater use before starting a cold engine is usually sufficient.
Prolonged use, of a block heater will not harm the engine or heater.
Mercedes-Benz of North America offers block heater kits for all Diesel models. Refer to the applicable Service Informations (Group 20) for installation instructions.
CAUTION:
Do not use or recommend starting aids such as ether or other materials often used by truck operators. Damage to glow plugs and prechambers would result.
1.5 Diesel Fuel Heater
In tests conducted by the Motor Vehicle Manufacturers Association with ten (10) different brands of diesel fuel, it was found that the cloud point (formation of solid wax crystals in the fuel) varied between -30°C (-22°F) and -9°C (+16°F). Operating difficulties such as loss of power or engine stalling (due to clogged fuel lines or fuel filters when operating at or below the cloud point of the diesel fuel used), can occur even after a successful cold Start. For more information on diesel fuel properties, refer to Section 2.2. "Selection of Diesel Fuel Blending for Winter Operation".
Fuel heaters, especially when used in combination with a block heater, are a safe, economical means to keep the fuel above the critical temperatures and assure trouble-free motoring under almost all ambient conditions.
Mercedes-Benz of North America offers in-line fuel heater kits for installation in all Diesel models. For detailed instructions, refer to the appropriate Service Information under Group 47.
We also suggest that you contact your local diesel fuel distributors for their fuel specifications as to the important properties for winter operation, such as cloud point, pour point and cetane rating in order to guide your customers accordingly.