Inspect cooling system for leaks - AR20.00-P-1010NKB

ENGINE 270 in MODEL 242 

ENGINE 270, 607, 651 in MODEL 117 

ENGINE 270, 607, 651 in MODEL 156 

ENGINE 270, 607, 651 in MODEL 176, 246 

Shown on vehicle with gasoline engine 

Fig 1: Inspecting Cooling System For Leaks

Courtesy of MERCEDES-BENZ USA

	Risk of injury  to skin and eyes suffering 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 containers. Wear protective gloves, protective clothing and safety glasses.	AS20.00-Z-0001-01A
	Checking prepared
1	Switch on ignition
2	Adjust heater to maximum heat output
3	Unscrew cap (1) on coolant expansion reservoir (2)	Unscrew cap (1) slowly and relieve overpressure.
4	Check coolant level and antifreeze content coolant
	Notes on coolant level		AH20.00-P-1142-01CW
		Coolant mixing ratio	*BF20.00-P-1001-04A
5	Screw on tester cap (3) at coolant expansion reservoir (2)	Test cap	Figure
6	Connect pressure pump (4) at tester cap (3)	Pressure pump	Figure
7	Apply test pressure to cooling system	Test pressure for pressure-testing the engine cooling system	*BE20.30-P-1005-01A
	Check
8	Check condition and coolant loss for all coolant carrying components and connections	If no coolant loss is seen: ↓ Check coolant carrying components for inner leaktightness. There is the possibility, for example, that coolant can find its way over a defective cylinder head gasket into the combustion chamber or over a defective water heat exchanger into the oil circuits.
9	Remove test pressure in the cooling system	To do this actuate pressure relief button on the pressure pump (4).
10	Detach pressure pump (4) from tester cap (3)
11	Unscrew on tester cap (3) at coolant expansion reservoir (2)
12	Switch off ignition
13	Check coolant level
	Notes on coolant level		AH20.00-P-1142-01CW
14	Screw cap (1) onto coolant expansion reservoir (2)

Fig 2: Identifying Pressure Pump (124 589 24 21 00)

Courtesy of MERCEDES-BENZ USA

Fig 3: Identifying Test Cap (210 589 00 91 00)

Courtesy of MERCEDES-BENZ USA