Remove/Install Coolant Lines - AR20.20-P-7441MRA

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Engine 274.9 in model 205 (except 205.048/049/148/248/348/349/448/449)

Engine 274.9 in model 253 (except 253.349/948/949)

Fig 1: Coolant Lines Components Location - Engine 274.9 In Model 253 (Except 253.349/948/949)

Courtesy of MERCEDES-BENZ USA

	Risk of injury to skin and eyes suffering scalding from contact with hot coolantspray. Risk of poisoning from swallowing coolant.	Do not open Cooling system unless coolant temperature is below 90°C. Open cap slowly and release the pressure. Do not pour coolant into beverage containers. Wear protective gloves, protective clothing and safety glasses.	AS20.00-Z-0001-01A
	Note on calculation of tightening torque when using insertion or socket tools with various effective lengths		AH00.00-P-0015-01CW
	Remove/install
1	Drain off coolant		AR20.00-P-1142LW
		: Only install front and lower center engine compartment paneling after performing a leak test.
2	Remove upper engine cover	: Only install upper engine cove after the leak test.
3	Remove air filter housing		AR09.10-P-1150MRA
4	Remove air intake pipe		AR09.10-P-8131MRA
5	Remove air filter housing holder	M8X1.25	*BA00.10-P-1005-04A
		M6X1	*BA00.10-P-1002-04A
6	Remove ATL heat shield		AR09.40-P-6025MRA
7	Remove coolant hose (5)	Hose clamp pliers	Fig 3
8	Remove screw/bolt (2)	Screw, coolant line to coolant pipe/cylinder head/crankcase/coolant thermostat/coolant hose	*BA20.10-P-1008-01AC
9	Unscrew screw/bolt (7)	Screw, coolant line to coolant pipe/cylinder head/crankcase/coolant thermostat/coolant hose	*BA20.10-P-1008-01AC
10	Remove coolant line (1) from coolant line (3)	: Replace sealing ring.
11	Remove screw/bolts (4)	Screw/bolt, coolant line to timing case/crankcase	*BA20.20-P-1001-01E
		Set of flexible head wrenches	Fig 2
12	Remove coolant line (3)	: Replace sealing ring.
13	Install in the reverse order
	Risk of accident from vehicle starting off by itself when engine running. Risk of injury (bruises and burns) resulting from working on the engine while it is being started or when it is running.	Secure vehicle to prevent it from starting off by itself. Wear closed and snug-fitting work clothes. Do not touch hot or rotating parts.	AS00.00-Z-0005-01A
14	Perform an engine test run and check engine for proper operation and leaktightness
15	Install front and center engine compartment paneling		AR61.20-P-1105LW
16	Install upper engine cover

METRIC SCREWS/BOLTS AND NUTS AS PER MBN 10 105, 10 143

Number	Designation		8.8	10.9
BA00.10-P-1002-04A	M6X1	Nm	9	13

METRIC SCREWS/BOLTS AND NUTS AS PER MBN 10 105, 10 143

Number	Designation		8.8	10.9
BA00.10-P-1005-04A	M8X1.25	Nm	22	32

COOLANT PUMP, COOLANT THERMOSTAT

Number	Designation			Engine 274
BA20.10-P-1008-01AC	Screw, coolant line to coolant pipe/cylinder head/crankcase/coolant thermostat/coolant hose	M6	Nm	9

RADIATOR, COOLANT HOSES

Number	Designation		Engine 274
BA20.20-P-1001-01E	Screw/bolt, coolant line to timing case/crankcase	Nm	20

Fig 2: Identifying Set Of Flexible Head Wrenches (001 589 81 09 00)

Courtesy of MERCEDES-BENZ USA

Fig 3: Identifying Hose Clamp Pliers (003 589 03 37 00)

Courtesy of MERCEDES-BENZ USA