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

ENGINES 271, 272, 642, 646, 651 in MODEL 204 

ENGINES 271, 272, 273, 642, 651 in MODEL 207 

ENGINES 271, 642, 651 in MODEL 212 

ENGINES 271 in MODEL 172 

Shown on engine 642 in model 212 

Fig 1: Inspecting Cooling System

Courtesy of MERCEDES-BENZ USA

	Checking
	Risk of injury  to skin and eyes caused by scalding from contact with hot coolant spray. Risk of poisoning  caused by 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
	Notes on coolant		AH20.00-N-2080-01A
1	Adjust heater to maximum heat output
2	Unscrew cap (1) slowly at expansion reservoir (2) and relieve overpressure
3	Check coolant level	Mixture ratio for coolant < mixture ratio for coolant>	*BF20.00-P-1001-04A
	Notes on coolant level		AH20.00-P-1142-01CW
4	Screw on test cap (3) at the expansion reservoir (2)	Tester cap	Fig 2
5	Connect pressure pump (4) at test cap (3)	Pressure pump	Fig 3
6	Apply test pressure to cooling system	To prevent damage to cooling system, do not exceed stated test pressure. Test pressure for pressure-testing cooling system	*BE20.30-P-1005-01A
7	Perform visual inspection on coolant carrying components	Check condition and coolant loss for all coolant carrying components and connections. The coolant carrying components should be checked for inner leaktightness if there is no external coolant loss. 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. Check condition and seating of the Henn coupling; replace catch springs as required in order to avoid coolant loss. See "Open and close Henn coupling".	AR09.41-P-1311-01AL
8	Relieve test pressure in cooling system	To do this actuate pressure relief button on the pressure pump (4) Pressure pump	Fig 3
9	Detach pressure pump (4) at test cap (3)	Pressure pump	Fig 3
10	Unscrew test cap (3) at the expansion reservoir (2)	Tester cap	Fig 2
11	Check coolant level and antifreeze content coolant	Mixture ratio for coolant	*BF20.00-P-1001-04A
	Notes on coolant level		AH20.00-P-1142-01CW
12	Screw cap onto expansion reservoir (2)

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