Inspect cooling system for leaks (engine 272) - AR20.00-P-1010V

ENGINE 272.942, 271.944, 272.963 in MODEL 171 

Using model 171 with engine 271.944 as an example 

Fig 1: Identifying Coolant Expansion Reservoir

Courtesy of MERCEDES-BENZ USA

	Check
	Risk of injury  to skin and eyes caused by scalding from contact with hot coolant spray. 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 bottles. Wear protective gloves, protective clothing and eye protection.	-
1	Switch on ignition
2	Open engine hood		AR88.40-P-1000V
3	Screw off cap slightly at coolant expansion reservoir (2)	2-stage cap: Rotate cap half a revolution in an anti-clockwise direction and release pressure relief.
4	Unscrew cap.
5	Set heating switches to maximum heating capacity
6	Check coolant level	If the antifreeze protection of the coolant is inadequate, either antifreeze must be topped up, or the coolant must be replaced: ↓
		Drain coolant, fill.
		Engine 271	-
		Engine 272	AR20.00-P-1142VA
	Notes on coolant		AH20.00-N-2080-01A
	Notes on coolant level		AH20.00-P-1142-01V
7	Screw on the test cap (1) at the coolant expansion reservoir (2)		Fig 2
8	Connect tester (3) at test cap (1)		Fig 3
			Fig 2
9	Discharge cooling system with test	To prevent damage to the cooling system, do not exceed the stated test pressure	*BE20.30-P-1005-01A
		If new cylinder head gasket fitted, first of all warm up engine to operating temperature before testing cooling system for leaks.
10	Inspect condition and attachment of hose clamps, re-tighten or replace if necessary.	6 mm socket hexagon on flexible shaft for hose clamps with worm drive	*WH58.30-Z-1001-06A
		7 mm socket hexagon on flexible shaft for hose clamps with worm drive	*WH58.30-Z-1002-06A
11	Check coolant hoses and heater hoses and their connecting points for condition and coolant loss	If necessary, replace the coolant hoses and heater hoses.
12	Unscrew on the test cap (1) at the coolant expansion reservoir (2)
13	Remove tester (3)
14	Screw on cap at coolant expansion reservoir (2)
15	Close engine hood		AR88.40-P-1000V
16	Switch off ignition

Fig 2: Identifying Test Cap (210 589 00 91 00)

Courtesy of MERCEDES-BENZ USA

Fig 3: Identifying Pressure Pump (124 589 24 21 00)

Courtesy of MERCEDES-BENZ USA