Underbonnet check points
In-line engine shown - V6 is similar
A) Engine oil level dipstick
B) Engine oil filler cap
C) Coolant expansion tank
D) Brake fluid reservoir (unclip the cover for access)
E) Screen/headlight washer fluid reservoir
F) Power steering fluid reservoir
Engine oil level
Make sure that your car is on level ground
Check the oil level before the car is driven, or at least 5 minutes after the engine has been switched off.
If the oil is checked immediately after driving
the vehicle, some of the oil will remain in the upper engine components,
resulting in an inaccurate reading on the dipstick!
The correct oil
Modern engines place great demands
on their oil. It is very important that the correct oil for your car is used.
|Engine oil grade:
| Models without a diesel particulate filter
||5W/30 meeting Mercedes specification 228.3/228.5/228.51/229.3/229.31/229.5/229.51. Eg. Castrol Edge 5W30
| Models with diesel particulate filter
||5W/30 meeting Mercedes specification 228.51/229.31/229.51. Eg. Castrol Edge 5W30
If you have to add oil frequently, you should
check whether you have any oil leaks. Place some clean paper under the car
overnight, and check for stains in the morning. If there are no leaks, the
engine may be burning oil.
Vehicles with an engine oil level dipstick
Always maintain the level between the upper and
lower dipstick marks. If the level is too low severe engine
damage may occur. Oil seal failure may result if the engine is overfilled by
adding too much oil.
On all diesel models it is located on the left-hand rear side of the engine. See “Underbonnet Check Points” for the exact location of the dipstick.
Withdraw the dipstick. Using a clean rag or
paper towel, wipe all the oil from the dipstick. Insert the clean dipstick into
the tube as far as it will go, then withdraw it again.
Withdraw the engine oil level dipstick
Note the oil level on the end of the dipstick,
which should be between the upper MAX mark and the lower MIN mark.
The oil level should be between the upper MAX mark and the lower MIN mark
Oil is added through the filler cap on top of
the engine. Rotate the cap through a quarter-turn anti-clockwise and withdraw
it. Top-up the level. A funnel may help to reduce spillage. Add the oil slowly,
checking the level on the dipstick often. Do not overfill.
Add oil slowly through the filler cap apeture
Vehicles without an engine oil level dipstick
Some models have a red cap fitted to the dipstick tube, and not a dipstick. The engine oil level is checked on the multi-function display unit on the instrument panel. By pressing the up and down buttons repeatedly, the ENGINE OIL LEVEL, MEASURING NOW! will appear on the display. Follow the instructions shown to achieve the correct level. If you need to renew the oil and filter, click below
DO NOT attempt to remove the expansion tank
pressure cap when the engine is hot, as there is a very great risk of scalding.
Do not leave open containers of coolant about, as it is poisonous.
With a sealed-type cooling system, adding coolant should not
be necessary on a regular basis. If frequent topping-up is required, it is
likely there is a leak. Check the radiator, all hoses and joint faces for signs
of staining or wetness, and rectify as necessary.
It is important that antifreeze is used in the
cooling system all year round, not just during the winter months. Don’t top-up
with water alone, as the antifreeze will become too diluted.
||Mercedes Benz Long life coolant to specification M325.6 (refer to the for the latest specifications)
The coolant level varies with the temperature of
the engine. When the engine is cold, the coolant level should be level with the marker bar withing the filler neck. When the engine is hot, the level will rise approximately 15 mm.
If topping-up is necessary, wait until the engine is cold, then slowly unscrew the expansion
tank filler cap anti-clockwise, to release any pressure in the system, and
Unscrew the coolant expansion tank filler cap
Add a mixture of water and antifreeze through
the expansion tank filler neck, until the coolant is level with the marker bar in the filler neck.
Refit the cap, turning it clockwise as far as it will go until it is secure.
Add coolant to the expansion tank...
...until it is level with the marker bar in the filler neck. Should you need to replace the coolant, click below
Brake/clutch fluid level
Brake fluid can harm your eyes and damage
painted surfaces, so use extreme caution when handling and pouring it.
Do not use fluid that
has been standing open for some time, as it absorbs moisture from the air,
which can cause a dangerous loss of braking effectiveness.
The fluid level in the reservoir will drop
slightly as the brake pads wear down, but the fluid level must never be allowed
to drop below the “MIN” mark.
If the reservoir requires repeated topping-up
this is an indication of a fluid leak somewhere in the system, which should be
The brake master cylinder and fluid reservoir
are mounted in the engine compartment on the
right-hand side of the bulkhead. The MAX and MIN level marks are indicated on
the side of the reservoir and the fluid level should be maintained between
these marks at all times. The MAX level is also indicated within the filler neck.
On some models, rotate the fasteners anti-clockwise and remove the cover from above the master cylinder
On other models, remove the cover over the fluid reservoir
The MAX and MIN levels are shown on the side of the reservoir
On manual transmission models, the clutch master cylinder is supplied with fluid from the brake master cylinder reservoir.
If topping-up is necessary, wipe the area around
the filler cap with a clean rag before removing the cap. It’s a good idea to
inspect the reservoir. The fluid should be changed if dirt is visible.
Wipe around the filler cap
Carefully add fluid, avoiding spilling it on
surrounding paintwork. Use only DOT 4 PLus fluid; mixing different
types of fluid can cause damage to the system and/or a loss of braking
effectiveness. After filling to the correct level, refit the cap securely. Wipe
off any spilt fluid.
Place rags around the filler neck to absorb any spillage
Screen/headlight washer fluid level
not only keep the windscreen clean during foul weather, they also prevent the washer system freezing in cold
weather - which is when you are likely to need it most. Don’t top up using
plain water as the screenwash will become too diluted, and will freeze during
On no account use
coolant antifreeze in the washer system - this could discolour or damage
The reservoir for the windscreen and rear window, and healight (where applicable) washer systems is located in the front right-hand corner of
the engine compartment. If topping up is necessary, open the cap.
Open the windscreen/headlight washer fluid reservoir cap
When topping-up the reservoir a screenwash
additive should be added in the quantities recommended on the container.
Top up the screen/headlight washer reservoir. It could also be time to replace the wiper blades. For details, click below
Check the condition of the wiper blades. If they are cracked or show any signs of deterioration, or if the glass swept area is smeared, renew them. For maximum clarity of vision, wiper blades should be renewed annually, as a matter of course.
Front wiper blades
Set the wipers in the
Fold the wiper arms away from the windscreen.
Do not attempt to fold the arms away from the windscreen when they at not at the vertical position, otherwise damage to the bonnet may result.
Position the blade at 90° to the arm...
. . . and slide it from the arm.
Rear wiper blade
Pull the blade away from the screen, rotate it 90°, depress the clip and slide it from the arm.
Power steering fluid
For the check to be accurate, the steering must not be turned once the engine has been stopped.
Remove the plastic cover from the top of the engine.
Undo the fasteners and remove the cover - in-line engines
Pull the cover up from the rubber mountings - V6 engines
The reservoir is mounted at the left-hand side of the engine compartment.
Power steering fluid reservoir cap
Wipe clean the area around the filler cap, then unscrew it from the reservoir. The level should be at the MAX mark on the dipstick, depending on the temperature of the fluid.
MAX and MIN marks on the dipstick are given for 80°C and 20°C
If topping-up is necessary, use the specified type of fluid - do not overfill the reservoir. Take care not to introduce dirt into the system when topping-up. When the level is correct, securely refit the cap.
Only top up using the specified type of fluid
|Power steering fluid
||Pentosin hydraulic fluid. MB part No. A 001 989 24 03 10