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

ENGINE 177, 274.9, 276.8, 626, 651 in MODEL 205 

ENGINE 274.9, 651 in MODEL 253 

Shown on engine 276.8 

Fig 1: Inspecting Cooling System For Leaks - Shown On Engine 276.8

Courtesy of MERCEDES-BENZ USA

	Remove
1	Adjust heater to maximum heat output
2	Unscrew cap (1) slowly on coolant expansion reservoir (2) and reduce overpressure
3	Check coolant level and antifreeze content coolant	Coolant mixing ratio	*BF20.00-P-1001-04A
4	Screw tester cap (3) onto coolant expansion reservoir (2)	Test cap	Fig 3
5	Connect pressure pump (4) at test cap (3)	Pressure pump	Fig 2
6	Apply a test pressure to the engine cooling system for 2 minutes	Do not exceed the specified test pressure. Damage can occur on the engine cooling system otherwise. There should be no loss of pressure within a period of 2 minutes.
		Engine 274, 276, 626, 651 in model 205 Engine 274, 651 in model 253 Test pressure for pressure-testing the engine cooling system	*BE20.30-P-1005-01A
		Engine 177 in model 205 Test pressure for pressure-testing the cooling system	*BE20.30-P-1002-01D
	Check
7	Perform a visual inspection on the components carrying coolant	In the event of pressure loss. Check condition and coolant loss for all coolant carrying components and connections. Replace components as required and refill coolant.
	Install
8	Remove overpressure over the valve at the pressure pump (4) and remove pressure pump (4)	Pressure pump	Fig 2
9	Unscrew tester cap (3) at coolant expansion reservoir (2)	Test cap	Fig 3
10	Check coolant level and antifreeze content coolant	If necessary.
		Coolant mixing ratio	*BF20.00-P-1001-04A
11	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