Date of printing:

05/16/2022

Online Owner's Manual [In depth | Maintenance and care | Engine compartment]

Owner's Manual version: 06-13

Note: The online Owner's Manual is the latest version available. Deviations between this manual and items specific to your vehicle may occur since Mercedes-Benz constantly adapts its vehicles to the latest technology and modifies design and equipment. Please note that this online Owner's Manual does not under any circumstances replace the printed Owner's Manual which is supplied with the vehicle.

Engine compartment

Print page

Quick access

Contents

Bonnet
Overview of the engine compartment
Engine oil
Coolant
Brake fluid
Windscreen washer system/headlamp cleaning system
Fuel system

Bonnet

Opening the bonnet

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WARNING

An unlocked bonnet may open while driving and block your view. There is a risk of an accident.

Never unlock the bonnet while driving.

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WARNING

If you open the bonnet while the engine is overheating or while there is a fire in the engine compartment, you could come into contact with hot gases or other leaking service products. There is a danger of injury.

Allow an overheating engine to cool down before opening the bonnet. If there is a fire in the engine compartment, leave the bonnet closed and notify the fire brigade.

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WARNING

Certain components in the engine compartment could be very hot, e.g. the engine, the radiator and parts of the exhaust system. There is a risk of injury when accessing the engine compartment.

As far as possible, allow the engine to cool down and only touch the following components.

If you have to carry out work in the engine compartment, only touch the following components:

  • Bonnet

  • Oil dipstick

  • Engine oil filler neck cap

  • Washer fluid reservoir cap

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WARNING

There are moving components in the engine compartment. Certain components may continue to move or suddenly move again even after the ignition has been switched off, e.g. the radiator fan. There is a risk of injury.

If you have to carry out work in the engine compartment:

  • switch off the ignition

  • never touch the dangerous areas surrounding moving components, e.g. the rotation area of the fan

  • remove jewellery and watches

  • keep items of clothing and hair, for example, away from moving parts.

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WARNING

The ignition system and the fuel injection system operate with a high voltage. If you touch the live components, you could receive an electric shock. There is a danger of injury.

Never touch components of the ignition system or the fuel injection system when the ignition is switched on.

The live components of the fuel injection system are, for example, the injectors.

The live components of the ignition system are, for example:

  • ignition coils

  • spark plug connectors

  • diagnostic sockets

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Make sure that the windscreen wipers are not folded away from the windscreen. Otherwise, you could damage the windscreen wipers or the bonnet.

images/img18831411ab8d3a71351f191551e8947f_1_--_--_JPG72.jpg

Stop your vehicle as far away from traffic as possible on level ground.

Switch off the engine.

Secure the vehicle to prevent it from rolling away.

Pull release handle mbsymb6_inv_003a.png on the bonnet.

The bonnet is released.

images/imge9395e21ab8db546351f1915389c55af_1_--_--_JPG72.jpg

Grasp in the gap and push grip mbsymb6_inv_003b.png on the bonnet catch upwards.

Raise the bonnet and hold it in that position.

images/imgde99628c351f151432807c4c5d14a651_1_--_--_JPG72.jpg

Pull support strut mbsymb6_inv_003f.png out of retainer mbsymb6_inv_003d.png and guide it up in the direction of the arrow.

Lower the bonnet in such a way that support strut mbsymb6_inv_003f.png glides into recess mbsymb6_inv_0041.png and the bonnet engages.

Closing the bonnet

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WARNING

Cloths or other flammable materials left in the engine compartment can ignite if they come into contact with the exhaust system or parts of the engine that heat up. There is a risk of fire. After carrying out maintenance work, make sure that no extraneous flammable material is left in the engine compartment or on the exhaust system.

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WARNING

An unlocked bonnet may tip forwards during heavy deceleration and may strike persons or objects in the swinging range. There is a risk of an accident and injury.

Make sure that the bonnet is correctly closed and locked before each journey.

If the bonnet is not locked and you are already driving at walking pace:

  • the yellow mbsymb1_inv_0031.png indicator lamp in the instrument cluster goes on for vehicles without steering-wheel buttons.

  • the mbsymb1_inv_0031.png Bonnet open display appears for vehicles with steering-wheel buttons.

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Do not use your hands to push the bonnet down. You could damage it otherwise.

Hold support strut mbsymb6_inv_003f.png and lift the bonnet slightly.

Guide support strut mbsymb6_inv_003f.png towards retainer mbsymb6_inv_003d.png and apply slight pressure to make it engage.

Lower the bonnet and allow it to fall with momentum from a height of approximately 30 cm.

The bonnet locks audibly.

Check that the bonnet is correctly locked.

If the bonnet can be raised slightly, it is not properly engaged.

If the bonnet is not correctly engaged, open the bonnet again. Let the bonnet fall with a little more momentum.

Nach oben

Overview of the engine compartment

images/img22de295b44eae0e835477e682bf02bf0_1_--_--_JPG72.jpg Engine compartment (example, diesel engine) images/img092bba2c1396fb6c351f19144d42d698_1_--_--_JPG72.jpg Engine compartment (example, petrol engine)
mbsymb6_inv_003a.png Engine oil filler neck cap more
mbsymb6_inv_003b.png Brake fluid reservoir cap more
mbsymb6_inv_003d.png Coolant expansion tank cap more
mbsymb6_inv_003f.png Washer fluid reservoir cap more

Regularly check the fluid level and the assembly for leaks. If you detect fluid loss, e.g. oil flecks on the vehicle parking space, consult a qualified specialist workshop immediately.

Nach oben

Engine oil

General notes

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Engine oil gets dirty in the course of operation and its quality and volume are gradually diminished. Regularly check the oil level, and top up or have it replaced as needed.

Observe the information on approved engine oils and oil consumption in the "Technical data" section more.

You can check the oil level in the engine:

  • on the display of the on-board computer (vehicles with a diesel engine)

  • with the oil dipstick

Depending on the engine, the oil dipstick can be found in various locations.

Checking the oil level shown in the display

If at extremely low temperatures no engine oil level is displayed after 5 minutes, repeat the engine oil level check after another 5 minutes.

If an oil level reading is still not displayed, check the engine oil level with the dipstick. Have the oil level display checked at a qualified specialist workshop.

Only check the oil level when the engine is at normal operating temperature.

Park the vehicle on a level surface.

Switch off the engine.

Wait for five minutes.

Turn the key to position 2 in the ignition lock.

The display is activated.

Vehicles without steering wheel buttons: press the mbsymb3_inv_0034.png menu button on the instrument cluster more repeatedly until the display shows the mbsymb1b_inv_0031.png symbol.

The --:-- display message appears in the display while the engine oil level measurement is running.

Vehicles with steering wheel buttons: press the mbsymb2_inv_00cb.png service button on the instrument cluster more.

The mbsymb1b_inv_0034.png Engine oil level Measuring in progress! display message appears in the display while the engine oil level measurement is in progress.

Display message for vehicles without steering-wheel buttons: the display may show the following messages after the engine oil level measurement.

mbsymb1b_inv_0031.png

Action

OK

Do not top up oil.

- 1.0 ltr

Top up with the amount of oil shown more.

Check the engine oil level again after a few minutes.

- 1.5 ltr

- 2.0 ltr

HI

The oil level is too high.

Have excess oil siphoned off.

Display message for vehicles with steering-wheel buttons: the display may show the following messages after the engine oil level measurement.

mbsymb1b_inv_0031.png

Action

Engine oil level OK

Do not top up oil.

Engine oil Add 1.0 l

Top up with the amount of oil shown more.

Check the engine oil level again after a few minutes.

Engine oil Add 1.5 l

Engine oil Add 2.0 l

Engine oil level Reduce oil level

The oil level is too high.

Have excess oil siphoned off.

Eng. oil lev. Turn ignition on for level

Turn the key to position 2 in the ignition lock.

Observe wait. period

Repeat the engine oil measurement after about 5 minutes if the engine is at normal operating temperature.

Repeat the engine oil measurement after about 30 minutes if the engine is not at normal operating temperature.

Engine oil level Not when eng. running

Switch off the engine and wait for approximately 5 minutes if the engine is at normal operating temperature. Then, perform the engine oil measurement.

Checking the oil level using the oil dipstick

images/img99a8ff92d0dd0f1c35477e6813341334_1_--_--_JPG72.jpg Oil dipstick and engine oil filler neck (example: diesel engine)
images/img959bb72337e203a2351f19144edb9101_1_--_--_JPG72.jpg Oil dipstick and engine oil filler neck (example: petrol engine)

Only check the oil level when the engine is at normal operating temperature.

Stop your vehicle as far away from traffic as possible on level ground.

Secure the vehicle to prevent it from rolling away.

Switch off the engine.

Wait for five minutes.

Open the bonnet more.

Pull out oil dipstick mbsymb6_inv_003a.png.

Wipe oil dipstick mbsymb6_inv_003a.png using a lint-free cloth.

Insert oil dipstick mbsymb6_inv_003a.png back into the guide tube as far as it will go and remove it again.

If the level is between minimum mark mbsymb6_inv_003d.png and maximum mark mbsymb6_inv_003b.png, the oil level is correct.

If the oil level has dropped to or below minimum mark mbsymb6_inv_003d.png, open cap mbsymb6_inv_003f.png and top up the engine oil more.

The difference in quantity between marks mbsymb6_inv_003b.png and mbsymb6_inv_003d.png is approximately 2 l.

Close the bonnet.

Topping up the engine oil

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WARNING

If engine oil comes into contact with hot components in the engine compartment, it may ignite. There is a risk of fire and injury.

Make sure that engine oil does not spill out over the filler neck. Allow the engine to cool down and thoroughly clean the components that have come into contact with engine oil before you start the engine.

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Environmental note

When topping up the oil, take care not to spill any. If oil enters the soil or waterways, it is harmful to the environment.

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Do not add too much oil. Topping up with too much engine oil can result in damage to the engine or to the catalytic converter. Have excess engine oil siphoned off.

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Do not use any additives with the engine oil. This could damage the engine.

Open the bonnet more.

Unscrew and remove cap mbsymb6_inv_003f.png.

Top up the engine oil.

Fit cap mbsymb6_inv_003a.png on the filler neck and tighten.

When doing so, make sure that the cap engages correctly.

Check the oil level with the oil dipstick more or on the display more.

Close the bonnet.

Nach oben

Coolant

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WARNING

Service product can be poisonous and hazardous to health. There is a risk of injury.

Observe the instructions on the respective original container when using, storing and disposing off service products. Always store service products in the sealed original container. Always keep service products out of the reach of children.

Coolant contains glycol and is therefore poisonous. Observe also the safety notes in the "Service products and capacities" section more.

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WARNING

The engine cooling system is under pressure, particularly if the engine is warm. You could be scalded by hot coolant spraying out when opening the cap. There is a danger of injury.

Allow the engine to cool before opening the cap. Wear gloves and protective eyewear when opening. Slowly turn the cap half a turn to allow pressure to escape.

Only check the coolant level and/or fill the coolant if the vehicle is on a level surface and the engine has cooled down. The coolant temperature must be below 50 corposwgl_2020.png .

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Check the engine cooling and heating system regularly for leaks.

If a large quantity of coolant is lost, have the cause traced and rectified at a qualified specialist workshop.

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WARNING

If antifreeze comes into contact with hot components in the engine compartment, it may ignite. There is a risk of fire and injury.

Let the engine cool down before you top up the antifreeze. Make sure that antifreeze is not spilled next to the filler neck. Thoroughly clean the antifreeze from components before starting the engine.

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Take care not to spill any coolant on painted surfaces. You could otherwise damage the paintwork.

images/imgc63472f422da0db4351f19153a09c8e4_1_--_--_JPG72.jpg Example: cap and coolant expansion tank

Checking the coolant level

Stop your vehicle as far away from traffic as possible on level ground.

Switch off the engine.

Secure the vehicle to prevent it from rolling away.

Open the bonnet more.

Slowly turn cap mbsymb6_inv_003a.png half a turn anti-clockwise to allow excess pressure to escape.

Turn cap mbsymb6_inv_003a.png further and remove it.

Check the coolant level.

If the coolant reaches the maximum mark on coolant expansion tank mbsymb6_inv_003b.png, there is enough coolant in coolant expansion tank mbsymb6_inv_003b.png.

Topping up the coolant

If the coolant drops under the minimum mark on coolant expansion tank mbsymb6_inv_003b.png top up the coolant to the maximum mark.

Observe the information on coolant mixture ratio and water quality in the "Technical data" section more. To prevent damage to the engine cooling system, use only approved corrosion inhibitor/antifreeze that complies with the Mercedes-Benz Specifications for Service Products.

Replace cap mbsymb6_inv_003a.png and turn it clockwise to tighten.

Start the engine.

After approximately h5 minutes, switch off the engine and allow it to cool down.

Check the coolant level again and top up the coolant if necessary.

Close the bonnet.

Nach oben

Brake fluid

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WARNING

Service product can be poisonous and hazardous to health. There is a risk of injury.

Observe the instructions on the respective original container when using, storing and disposing off service products. Always store service products in the sealed original container. Always keep service products out of the reach of children.

Brake fluid is hazardous to health. Observe also the safety notes in the "Service products and capacities" section more.

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WARNING

The brake fluid continuously absorbs moisture from the air. This results in the boiling point of the brake fluid lowering. If the boiling point of the brake fluid is too low, vapour pockets may form when the brakes are subjected to a heavy load. This would impair braking efficiency. There is a risk of an accident.

Have the brake fluid renewed at the prescribed intervals.

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If the brake fluid level in the brake fluid reservoir has fallen to the minimum mark or less, check the brake system immediately for leaks. Also check the thickness of the brake pads/linings. Visit a qualified specialist workshop immediately.

Do not top up the brake fluid. This does not solve the problem.

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Brake fluid corrodes paint, plastic and rubber. If brake fluid comes into contact with paint, plastic or rubber, rinse with water immediately.

Have the brake fluid renewed every 2 years at a qualified specialist workshop. Observe the information on brake fluid in the "Technical data" section more.

images/img2c14783a22e02221351f19154fc74891_1_--_--_JPG72.jpg

The clutch mechanism and the brake system are operated hydraulically using brake fluid.

Check the brake fluid level regularly, e.g. weekly or when refuelling.

Checking the brake fluid level

Stop your vehicle as far away from traffic as possible on level ground.

Switch off the engine.

Secure the vehicle to prevent it from rolling away.

Open the bonnet more.

Check the brake fluid level.

The brake fluid level is correct if the level is between the MIN mark and MAX mark on brake fluid reservoir mbsymb6_inv_003a.png.

Close the bonnet.

Nach oben

Windscreen washer system/headlamp cleaning system

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WARNING

Windscreen washer concentrate is highly flammable. If it comes into contact with hot engine components or the exhaust system it could ignite. There is a risk of fire and injury.

Make sure that no windscreen washer concentrate is spilled next to the filler neck.

../../../../global/pictures_mb/symb_ruf.png

Only use washer fluid that is suitable for plastic lamp lenses, e.g. MB SummerFit or MB WinterFit. Unsuitable washer fluid could damage the plastic lenses of the headlamps.

images/imgc970e13823335c8b351f1915690648e8_1_--_--_JPG72.jpg Example: washer fluid reservoir

Add windscreen washer concentrate to the washer fluid all year round. Observe the information on washer fluid in the "Technical data" section more.

Topping up the washer fluid

Mix the washer fluid to the appropriate mixing ratio in a container beforehand.

Open the bonnet more.

Pull cap mbsymb6_inv_003a.png on the washer fluid reservoir upwards at the tab.

Top up with the premixed washer fluid.

Press cap mbsymb6_inv_003a.png onto the filler neck until it engages audibly.

Close the bonnet.

Nach oben

Fuel system

Draining the fuel filter

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WARNING

Fuel is highly flammable. Improper handing of fuel creates a risk of fire and explosion.

Avoid fire, naked flames, smoking and creating sparks under all circumstances. Switch off the ignition and auxiliary heating before carrying out work to the fuel system. Always wear protective gloves.

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Environmental note

Dispose of the water-fuel mixture in an environmentally responsible manner.

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If the mbsymb1b_inv_003a.png indicator lamp lights up, drain the fuel filter with water separator immediately. Otherwise, the engine may be damaged.

images/imgfcdca1021d76e6f235477e6838e838e8_1_--_--_JPG72.jpg 4-cylinder engine images/img00c6566f351f1515184028cd70ebd9b5_1_--_--_JPG72.jpg 6-cylinder engine

Vehicle with a diesel engine: if the mbsymb1b_inv_003a.png indicator lamp in the instrument cluster goes on, drain the fuel filter with water separator immediately.

Mercedes-Benz recommends that you have this maintenance work carried out at a qualified specialist workshop.

Park the vehicle safely and secure it from rolling away.

Switch off the auxiliary heating system more.

Switch off the engine.

Open the bonnet more.

If necessary, pull out drain hose mbsymb6_inv_003a.png from the retaining clamp and guide it downwards with the opening first.

Place a suitable receptacle under drain hose mbsymb6_inv_003a.png.

Turn the key to position 2 in the ignition lock.

Open drain plug mbsymb6_inv_003b.png immediately until the water/fuel mixture flows out of drain hose mbsymb6_inv_003a.png.

Screw in drain plug mbsymb6_inv_003b.png as soon as approximately 0.2 litres of the water/fuel mixture have been collected.

The electrical fuel pump halts the flow of the water/fuel mixture after 30 seconds.

After draining, turn the key back to position 0 in the ignition lock.

Dispose of the collected water/fuel mixture in an environmentally responsible manner, e.g. at a qualified specialist workshop.

If necessary, press drain hose mbsymb6_inv_003a.png into the retaining clamp and fix it in place.

Check drain plug mbsymb6_inv_003b.png. The drain plug must be closed.

When the engine is running and drain hose mbsymb6_inv_003b.png is open, fuel is lost through drain hose mbsymb6_inv_003a.png.

Close the bonnet.

If the mbsymb1b_inv_003a.png indicator lamp does not go out after draining:

Drain the fuel filter again.

If the mbsymb1b_inv_003a.png indicator lamp does not go out after draining for the second time, have the cause checked immediately at a qualified specialist workshop.

Nach oben

Notes

Date of printing:

05/16/2022

Online Owner's Manual [In depth | Maintenance and care | Engine compartment]

Owner's Manual version: 06-13

Note: The online Owner's Manual is the latest version available. Deviations between this manual and items specific to your vehicle may occur since Mercedes-Benz constantly adapts its vehicles to the latest technology and modifies design and equipment. Please note that this online Owner's Manual does not under any circumstances replace the printed Owner's Manual which is supplied with the vehicle.