How to Start a Diesel Mercedes in Cold Weather

Written by kelvin hayes
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How to Start a Diesel Mercedes in Cold Weather
Mercedes engines can be hard to start in cold weather. (mercedes benz g-class gelandewagen luxury suv car image by alma_sacra from

Mercedes diesel engines are known for their longevity and reliability. However, these engines utilise a slower burning fuel that is often susceptible to gelling in cold conditions, making cold weather starting difficult.

Skill level:

Things you need

  • Engine block heater
  • Synthetic oil
  • Diesel #1
  • Battery charger

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  1. 1

    Locate and unscrew oil drain plug to drain oil.

  2. 2

    Screw in oil drain bolt.

  3. 3

    Refill oil reservoir with synthetic oil.

    This is an essential step in preparing your Mercedes Diesel engine for cold weather starts. It's important to understand that synthetic oil differs from mineral based oil primarily in its resistance to thickening at lower temperatures.

    By resisting thickening in cold weather, the engine oil flows more easily, allowing for less engine resistance during the cold start.

  1. 1

    Purchase an engine block heater.

    This can be done online, however it's recommended that you make your purchase at a qualified Mercedes part supplier. Depending on the year of your Mercedes, this will cost between £32 to £65 (labour not included), as of 2010.

    An engine block heater works by plugging into a wall socket, attaching to your coolant system and heating the coolant.

    For more information on how engine block heaters work click here:>

  2. 2

    Hire a qualified mechanic to install a heater element.

  3. 3

    Plug the heater into 110 AC volt outlet when you expect the engine to be off for several hours.

  1. 1

    Pump diesel #1 into your vehicle

    No. 1 diesel fuel is recommended in cold weather conditions due to its lower boiling point and lighter weight when compared to diesel No. 2. These attributes allow No. 1 to flow more easily through the engine while resisting gelling or clouding, a common issue with No. 2 Diesel in low temperatures.

  2. 2

    Mix No. 1 and No. 2 Diesel together. To save cost, you may mix 10 per cent No. 1 with 90 per cent No. 2 Diesel.

  3. 3

    Pour anti-gelling additive into fuel tank.

    This may be purchased at Walmart, Napa auto parts or any petrol station.

  1. 1

    Purchase battery charger. As the engine cools over a period of several hours, the water in the battery will also begin to cool, resulting in insufficient battery output to overcome the cold engine resistance. Keeping your battery fully charged ensures maximum output during a cold start. Battery chargers can be purchased at any auto parts store for approximately £13 to £65 as of October 2010.

  2. 2

    Connect the charger to the negative and positive terminals of the battery.

  3. 3

    Set the charger to trickle or 2 amp/12 volt setting. This will give your battery a slow charge over several hours, allowing you to leave the charge on all night without risk of damaging the battery cell.

Tips and warnings

  • If the temperature remains above -15 degrees C below zero Fahrenheit, you may be able to avoid the need for an engine block heater by simply completing multiple glow plug cycles.
  • Fill your battery with distilled water to increase its conductivity.
  • Ensure that the battery charger is unplugged while you attach it to the battery terminals.

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