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

ENGINES 156, 157, 272, 273, 275, 276, 278, 642, 651 in MODEL 221 

ENGINES 156, 157, 273, 275, 278 in MODEL 216 

Shown on engine 273 

Fig 1: Inspecting Cooling System For Leaks - Shown On Engine 273

Courtesy of MERCEDES-BENZ USA

	Removing
	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	Switch on ignition
2	Adjust heater to maximum heat output
3	Unscrew cap (1) slowly at expansion reservoir (2) and relieve overpressure
4	Check coolant level and antifreeze content coolant	Correct if necessary.
		Mixture ratio for coolant	*BF20.00-P-1001-04A
5	Screw on test cap (3) at the expansion reservoir (2)	Tester cap	Figure
6	Connect pressure pump (4) at test cap (3)	Pressure pump	Figure
7	Apply test pressure to cooling system	To prevent damage to cooling system, do not exceed stated test pressure.	*BE20.30-P-1005-01A
	Checking
8	Perform visual inspection of 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.	AR09.41-P-1311-01AL
	Install
9	Release overpressure over valve on pressure pump (4) and remove pressure pump (4)	Pressure pump	Figure
10	Unscrew test cap (3) at the expansion reservoir (2)	Tester cap	Figure
11	Switch off ignition
12	Check coolant level and antifreeze content coolant	Mixture ratio for coolant	*BF20.00-P-1001-04A
	Notes on coolant level		AH20.00-P-1142-01V
13	Screw cap (1) 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