Remove the oil filter cap using the
6
socket spanner insert (WAF 36). Allow oil to drain from the filter housing.
Unscrew cap 1 and oil filter element 3 and remove element 3 from the cap by pressing the lower edge on the sides.
Oil filter cap Engine: Oil change and filter
replacement
i
Only change engine oil when the engine is at normal operating temperature.
Risk of scalding
G
Hot engine oil spraying out can scald your skin and eyes.
Wear suitable protec tive gloves, protective clothing and eye protection.
!
Make sure that no foreign objects en ter the filter h ousing. Never wipe the filter housing out.
Work plans
6
Cap with oil filter element 1 Cap2 Sealing ring 3 Oil filter element
Replace the sealing ring on cap 2.
Insert new filter element in the cap and clip it into place by pressing on it.
Screw the cap on the oil filter housing and tighten it
Tightening torque: 25 Nm.
Extracting and draining the engine oil Extraction:
Extract the engine oil through the dip-stick guide pipe. To do this, pull out the dipstick an d insert the scavenging de-vice sealed with an O-ring into the guide pipe.
Dipstick guide pipe
!
Observe the operatin g instructions for the engine oil scavenging device.
Maintenance
Work plans6
Draining:
Place a suitable collecting receptacle under the drain plug on the undersid e of the oil sump.
Unscrew the drain plug carefully and al-low the oil to d rain out.
Oil drain plug
Renewing:
Screw the drain plug back in with a new sealing ring and tighten.
Tightening torque:
M20 x 1.5 – 60 Nm M26 x 1.5 – 85 Nm
Add new engine oil into the engine via th e oil filler neck up to the maximum mark on the d ipstick.
Oil filler neck
Environmental note
H
Dispose of engine oil and filters in ac cord-ance with the regulations in forc e at the place of use of the engine.
Work plans
6
Start the engine with the setpoint value sensor in the idling position. Monitor the oil pressure gauge.
Check the filter and drain plug for leaks.
Stop the engine. Check the oil level af-ter approximately 5 minutes. Top up oil to th e maximum mark on the dipstick if necessary.
!
Keep the engine running at idling speed until an oil pressure reading is dis-played. If no oil pressure is d isplayed after approximately 10 seconds, switch off the engine and establish the cause.
Maintenance
Work plans6
Layout of cylinders and valves
Special tools
Rotation device: 904 589 04 63 00 Valve clearance:
Adjusting the valve clearance
= inlet valve
= exhaust valve
= flywheel end
X
Inlet valves = 0.40 mm Exhaust valve = 0.60 mm
i
Adjust the valve clearance when the engine is cold (at least 30 minutes after the engine was stopped, even if it was only operated for a brief period).
Clean very dirty cylinder head co vers before removing.
Risk of injury
G
If not properly secured, a vehicle might acci-dentally be set in motion, knocking people down or trapping them and otherwise c aus-ing an accident and injuraus-ing you or others.
Always secure the vehicle against rolling away by applying the parking brake and, if nec essary, by placing chocks under the wheels.
Shift the transmission into neutral.
Only turn the engine over using the rota-tion device provided for this purpose.
Work plans
6
Removing and fitting the cylinder head cover
1 Charge-air manifold 2 Cylinder head cover 3 Allen bolt
4 Sealing washer 5 Cover seal
6 Engine breather hose
Removing:
Remove engine breather hose 6 from the cylinder head cover.
Unscrew Allen bolt 3 from the cylin-der head cover together with sealing washers4.
Remove cylinder head cover 2.
Fitting:
Clean the cylinder head and the cylin-der head cover sealing surfaces.
Check the gasket between the cylinder head cover an d charge-air manifold1 and replace if necessary.
Always replace the gasket between the cylinder head cover and the cylinder head.
Position the cylinder head cover.
Fit Allen bolts 3 with new sealing washers4 and tighten
Tightening torque: 30 Nm.
Flywheel housing inspection hole
Fit rotation device (904 589 04 63 00) on the flywheel housing inspection hole.
Maintenance
Work plans6
Adjusting the valve clearance
I – inlet valve E – exhaust valve
Adjust all valve clearan ces in 2 crankshaft positions.
Use the rotation device to turn the crankshaft un til no. 4 or 6 cylinder is at overlap TDC (no. 1 cylinder at ignition TDC). Then turn no. 1 cylinder to over-lap TDC (no. 4 or 6 cylinder at ignitio n TDC).
Check the valves in accordance with the above table and adjust.
Engine Cranksha ft position Cylinder/ valves to be adjusted
1 2 3 4 5 6
OM 904/ 924 LA 4th cylinder valve overlap I/ E I E
-1st cylinder valve overlap – E I I /E
OM 906/ 926 LA 6th cylinder valve overlap I/ E I E I E
-1st cylinder valve overlap – E I E I I/ E
Work plans
6
Checking and adjusting the va lve clearance
1 Adjustment screw 2 Counternut
Measure the valve clearance between the rocker arm and valve stem (exhaust valve) or valve bridge (inlet valve) with a feeler gauge (arrow).
It must be possible to pull the feeler gauge through with only light resist-ance.
Slacken counternut 2 to adjust the valve clearance. Adjust the valve clear-ance b y turning adjustment screw1.
Retighten the counternut.
Tightening torque: 25 Nm.
Check the valve clearance again and readjust if necessary.
Concluding work
Refit the cylinder head cover ( see page 74).
Remove the rotation device from the flywheel housing inspection hole.
Maintenance
Work plans6
Fuel prefilter 1 Cap
2 Filter element 3 Sealing ring
Open the tank cap to remove excess pressure in the fuel tank.
Clean the outside of the fuel prefilter and cover any hoses /lines under the prefilter.
Unscrew cap 1 and pull it out of the filter housing to gether with filter element2.
Clean cap 1 and filter element 2.
Replace the filter element if it is very dirty or damaged.
Check sealing ring 3 for the cap and replace if n ecessary.
Insert the filter element in the cap and screw the cap onto the filter housing.
Tightening torque: 25 Nm.
Fuel prefilter: Cleaning the filter
element Risk of fire
G
There is an increased risk of fire when han-dling fuels as they are highly flammable.
Avoid fire, naked flames and sparks and re-frain from smoking when handling fuels.
Environmental note
H
Dispose of used filter elements and fuel res-idue in ac cordance with current local regula-tions.
Work plans
6
Fuel prefilter with heated water separator*
1 Hand pump 2 Filter housing
3 Water separator (heated) 4 Water drain valve
Open the drain valve and loosen the vent screw. Collect the fuel/ water mixture from the filter element in a suitable receptacle.
Remove the heater connector.
Unscrew the filter element.
Remove the separator vessel from the filter element and clean or replace as necessary.
Refit in the reverse order. Use new sealing rings when fitting.
Fuel prefilter with heated water separa tor*: Repla cing the filter element
Risk of fire
G
There is an increased risk of fire when han-dling fuels as they are highly flammable.
Avoid fire, naked flames and sparks and re-frain from smoking when handling fuels.
Environmental note
H
Dispose of used filter elements and fuel res-idue in accordance with c urrent local regula-tions.
Maintenance
Work plans6
Close the drain valve and fill the pre-filter using the fuel hand pump. Then close the vent screw.
Start the engine and bleed the fuel sys-tem.
Check the pre-filter for leaks.
!
Screw the filter element onto the filter head tightly by hand.
i
Leave the engine running for approxi-mately 1 minute. The fuel system bleeds automatically.
Work plans
6
Fuel filter 1 Cap
2 Filter housing
Open the tank cap to prevent excess pressure in the fuel tank.
Unscrew fuel filter cap 1 with the socket sp anner insert (WAF 36).
Pull cap 1 and filter element slightly out of filter housing2. Allow fuel to flow out.
1 Cap 2 Sealing ring 3 Filter element 4 Dirt trap 5 Filter housing Replacing the fuel filter element
Risk of fire
G
There is an increased risk of fire when han-dling fuels as they are highly flammable.
Avoid fire, naked flames and the creation of sparks refrain from smoking when handling fuels.
Maintenance
Work plans6
Remove the cap and filter element. Un-clip filter element3 by pressing the lower edge of the filter element on the sides.
Pull dirt trap 4 out of the filter housing by the tabs.
Clean cap 1 and dirt trap 4.
Replace sealing ring 2.
Clip new filter element 3 into cap 1.
Lightly grease sealing ring 2 and the filter element seals.
Insert dirt trap 4 into filter housing 5; observe the correct installation po-sition.
Screw on cap and filter element and tighten.
Tightening torque: 25 Nm.
Start the engine and bleed the fuel sys-tem.
Check the fuel filter for leaks with the engine running.
!
Neither dirt nor water should enter the filter housing; do not empty dirt trap4 into the filter housing.
i
If the level of the diesel fuel in the tank is higher than the level of the engine, the feed line must be closed when re-placing the filter.
The diesel fuel could flow out.
i
Leave the engine running for approxi-mately 1 minute. The fuel system bleeds automatically.
i
To ensure the fuel system can be bled, the battery must have enough charge when the engine is started, since the fuel system must fill up with fuel first.
Work plans
6
Check the rubber sleeves, intake pipe and connection hoses for d amage and leaks.
Check the hose clamps, flanged joints and intake manifold for firm seating.
Intake pipe between air cleaner and engine: Checking for leaks and general condition
Maintenance
Work plans6
Special tools
Rotation device: 904 589 04 63 00
Fit the rotation device to the flywheel housing inspectio n hole.
Make a chalk mark on the poly-V-belt.
Check the poly-V-belt for damage in sec-tions; rotate the engine and poly-V-belt a little at a time
Flywheel housing inspection hole
rotate further using the rotation device until the chalk mark is reached again .
Remove the rotation device.
Poly-V-belt: Checking the condition
Risk of injury
G
Faulty poly-V-belts may tear and parts or all of the belt may be thrown off, thereby caus-ing injury to persons.
Always observe the specified mainte-nance intervals for poly-V-belts.
If damage is detected, replace the poly-V-belt c oncerned immediately.
i
Replace the poly-V-belt if one of the damage patterns shown on the next page is detected . For info rmation on in-stallin g and removing the p oly-V-belt ( see page 86).
Work plans
6
Maintenance
Work plans6
Damage patterns
1 Condition as new (as reference: trape-zoidal ribs)
2 One-sided wear: wedge-shaped ribs 3 Cord visible in the base of the ribs 4 Ribs split
5 Transverse cracks in several ribs 6 Rubber lumps in the base of the belt 7 Deposits of dirt or stones
8 Rib detached from the base of the belt 9 Cord torn out to the side
a Outer cord frayed
b Transverse cracks on the back of the belt
c Transverse cracks in several ribs
Work plans
6
Removing and installing the poly-V-belt
Spanner with extension in the tensioning device
1 Tensioning pulley 2 Spanner
Attach spanner 2 with the 17 mm socket to the hexagon bolt of tension-ing pulley1.
Swing the tensioning pulley upwards and remove the poly-V-belt.
Swing back the tensioning device.
Check that the tensioning device and belt pulley are in perfect condition (e.g.
check for worn bearings on the ten-sioning device, tenten-sioning p ulley and deflection pulleys as well as wear on belt pulleys); replace parts if necessary.
Lay the poly-V-belt (new) on all belt pul-leys, except for the tensioning pulley (see illustrations for poly-V-belt rout-ing).
Swing the tensioning pulley upwards using the lever, insert the poly-V-belt and swing back the tensioning pulley.
Remove the spanner and check for cor-rect seating of the poly-V-belt on the belt pulley.
Risk of injury
G
The tensioning devic e is spring-tensioned.
When it is loosened or tightened, there is a risk of injury from hands or fingers being crushed or trapped in pretensioned parts.
Make sure that the tool is handled cor-rectly.
Keep your fingers out of the area be-tween the belt pulley and the poly-V-belt when fitting or dismantling the poly-V-belt.
Wear work gloves when working on the tensioner.
Maintenance
Work plans6
Routing of the poly-V-belt (engine without refrigerant compressor)
1 Alternator 2 Coolant pump 3 Tensioning pulley 4 Crankshaft
Routing of the poly-V-belt (engine with refrigerant compressor)
1 Alternator 2 Coolant pump 3 Tensioning pulley 4 Refrigerant compressor 5 Deflection and guide pulley 6 Crankshaft
Work plans
6
Throttle valve lever in rest position 1 Throttle valve lever
2 Retainer
Throttle valve lever in working position 1 Throttle valve lever
2 Retainer
Checking the condition
Remove the wire circlip from the ball cup on the engine cylinder.
Force the ball cup off the ball neck of throttle valve lever 1.
Check the engine brake cylinder, ball neck and ball cup, and the throttle valve shaft for wear.
Check the firm seating of the throttle valve lever on the throttle valve shaft.
Tighten screws if n ecessary.
Grease the ball cup with the grease sp ecified.
Push the ball cup back onto the ball neck.
Fit the wire circlip.
Engine brake: Checking the condition a nd setting
Maintenance
Work plans6
Checking the a djustment
i
Throttle valve lever1 must lie against bracket2 in the operating position (cylinder extended) when the engine brake is operated.
When the engine brake cylin der (with the cylinder retracted) is in the rest po-sition, the throttle valve lever must also lie against the bracket; the pre-tension of the engine brake cylinder return spring is then sufficient.
Check the position of the throttle valve shaft: the no tches must be horizontal when th e engine brake is in the rest po-sition ( page 88, illustration on the left-hand side). The notches must be vertical in the working position ( page 88, illustration on the right-hand side).
Work plans
6
Open the engine cooling system radia-tor cap slowly. Relieve excess pres-sure.
Check the antifreeze/ corrosion inhibi-tor using testing device. The correct concentration of 50% by volume antifreeze /corro sion inhibitor in the coolant is indicated when there is anti-freeze protection down to –37°C. If less antifreeze p rotection is displayed, correct the mixing ratio.
Engine cooling system: Checking and correcting the fluid level and the antifreeze/ corrosion inhibitor
Risk of scalding
G
The cooling system is pressurised. Hot c ool-ant can spray out when the cooling system is opened and scald your skin and eyes.
Only open the cooling system at coolant temperatures below 90 °C.
Unscrew the sealing cap slowly and re-lease any excess pressure completely before opening the cap fully.
Wear suitable protective gloves, protec-tive clothing and safety goggles when handling coolant.
Risk of poisoning
G
There is a risk of poisoning if coolant is swal-lowed.
Never swallow coolant.
Never put coolant into containers nor-mally used for beverages.
Store coolant out of the reach of chil-dren.
!
Only use service products approved by DaimlerChrysler, ( see page 63).
i
Only check and correct the co olant lev-el when the coolant temperature is below 50 °C. Check the antifreeze/
corrosion inhibitor before correcting the coolant level. Only use prepared coolant with 50% by volume anti-freeze/corrosion inhibitor for topping up.
Maintenance
Work plans6
Check the coolant level.
The cooling system is correctly filled if the coolant reaches the mark in the filler neck.
The "Engine coolin g system: Checking and correcting the fluid level and antifreeze / corrosion inhibito r" work item must have already been carried out.
Carry out a visual inspection of the ra-diator for leaks and undamaged condi-tion.
Check the radiator for external dirt. The fins must not be dirty.
Check that all lines and hoses are un-damaged, that they are ro uted to avoid chafing and that they are secured in ac-cordance with the regulations.
!
If th e concentration is too low, there is a risk of engin e damage as a result of corrosion /cavitation in the cooling system.
!
Avoid con centrations of more than 55%
by volume antifreeze /corrosion inhibi-tor, otherwise maximum antifreeze pro-tection down to –45°C will not be achieved. If the concentration is higher, heat dissipatio n and antifreeze protec-tion deteriorate.
Cooling and heating system:
Checking for leaks and general condition
!
If damage /faults are found, repair the radiator or replace it.
Work plans
6
Special tool:
Pressure tester 001 589 83 21 00
On heating systems: Open the regulat-ing valves and shutoff valves.
Remove the coolant expansion tank cap.
Fit the testing equipment.
Pressure tester special tool
Risk of scalding
G
The cooling system is pressurised. Hot c ool-ant can spray out when the cooling system is opened and scald your skin and eyes.
Only open the cooling system at coolant temperatures below 90 °C.
Unscrew the sealing cap slowly and re-lease any excess pressure completely before opening the cap fully.
Wear suitable protective gloves, protec-tive clothing and safety goggles when handling coolant.
Risk of poisoning
G
There is a risk of poisoning if coolant is swal-lowed.
Never swallow coolant.
Never put coolant into containers nor-mally used for beverages.
Store coolant out of the reach of chil-dren.
Maintenance
Work plans6
Connect the compressed-air hose with the tyre inflator connection to the valve and build up a test pressure equal to the cooling system opening pressure.
The cooling system opening pressure can be seen on the code on the cap or pressure relief valve.
Example: Code 70 = 0.7 bar pressure.
i
A pressure relief valve is integrated in the testing equip ment so that a p res-sure of 1.2 bar cannot be exceeded.
Work plans
6
Renewing coola nt
Risk of scalding
G
The cooling system is pressurised. Hot c ool-ant can spray out when the cooling system is opened and scald your skin and eyes.
Only open the cooling system at coolant temperatures below 90 °C.
Unscrew the sealing cap slowly and re-lease any excess pressure completely before opening the cap fully.
Wear suitable protective gloves, protec-tive clothing and safety goggles when handling coolant.
Risk of poisoning
G
There is a risk of poisoning if coolant is swal-lowed.
Never swallow coolant.
Never put coolant into containers nor-mally used for beverages.
Store coolant out of the reach of chil-dren.
!
Only use antifreeze/ corrosion inhibitor approved b y Mercedes-Benz
( see page 59).
i
Before renewing the coolant, check the cooling and heating system for leaks and condition. Have the coolant renew-al confirmed in the Mainten ance Book-let.
Maintenance
Work plans6
Draining coolant
Open the engine cooling system radia-tor cap slowly. Let off excess p ressure and remove the radiator cap.
On heating systems: Open the heating temperature selector (regulating valve).
Coolant drain plug
Place the drain hose on the coolant drain plug on th e engine (arrow).
Loosen the drain plug (1 to 2 turns) The coolant flows out.
Risk of scalding
G
Hot coolant will scald your skin and eyes.
Only carry out work on the cooling
Only carry out work on the cooling