Inspecting cooling system for leaks - AR20.00-P-1010GZC

ENGINES 272, 273 in MODEL 164, 251 

ENGINES 273 in MODEL 463 

ENGINES 276 in MODEL 251 

Shown on model 251 with engine 272 

Fig 1: Identifying Coolant Expansion Reservoir, Tester Cap, And Pressure Pump

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
1	Unscrew cap for coolant expansion reservoir (1)	Unscrew cap slowly and relieve excess pressure.
2	Check coolant level and antifreeze content of coolant and correct if necessary	If the antifreeze protection for the coolant is too small, either antifreeze must be added or the coolant must be replaced: ↓ Drain coolant, fill. Model 164, 251	AR20.00-P-1142GZC
		Model 463	AR20.00-P-1142GX
	Coolant specifications	Sheet 310.1	BB00.40-P-0310-01A
	Anticorrosion/antifreeze agents (Sheet 325.0)	Sheet 325.0	BB00.40-P-0325-00A
3	Screw test cap (2) onto coolant expansion reservoir (1).		Fig 2
4	Connect pressure pump (3) at tester cap (2)		Fig 3
5	Apply test pressure to cooling system	To prevent damage to cooling system, do not exceed stated test pressure.	*BE20.30-P-1005-01A
6	Check hose clamps for condition and seating	Tighten hose clamps as necessary; replace if necessary.
7	Check coolant hoses and heater hoses and their connecting points for condition and coolant loss	Replace coolant hoses and heater hoses if required.
8	Unscrew test cap (2) at coolant expansion reservoir (1).	Unscrew test cap (2) slowly and relieve excess pressure.
9	Remove pressure pump (3) from test cap (2)
10	Screw cap onto coolant expansion reservoir (1)

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