Remove/install chain tensioner - AR05.10-P-7800MMB

ENGINE 157, 278 IN MODEL 216, 221 

Shown on right chain tensioner 

Fig 1: Identifying Chain Tensioner Remove/Install Components - Shown On Right Chain Tensioner

Courtesy of MERCEDES-BENZ USA

	Remove/Install
1.1	Rotate engine at crankshaft center bolt in direction of engine rotation to a 40°crank angle (CA) after top dead center (TDC) on cylinder 1 (ignition TDC)	To remove the left chain tensioner (1)
			AR05.10-P-7620-04MM
		For a removed cylinder head cover the engine musty not be turned without a mounted hold-down tool. Damage will occur to the camshafts and cylinder head otherwise.
		Socket wrench bit	Fig 2
		Tie-down set	Fig 4
1.2	Rotate engine at crankshaft center bolt in direction of engine rotation to a 40°crank angle after top dead center (overlap TDC) on cylinder 1 (overlap TDC)	To remove the right chain tensioner (1)
			AR05.10-P-7620-04MM
		For a removed cylinder head cover the engine musty not be turned without a mounted hold-down tool. Damage will occur to the camshafts and cylinder head otherwise.
		Socket wrench bit	Fig 2
		Tie-down set	Fig 4
2	Remove oil filter element	To remove the left chain tensioner (1)
			AP18.00-P-0101-06TMG
			*BA18.20-P-1001-01Y
		Engine 278 in model 216, 221 Mount, oil filter housing cover
		Wrench socket	Fig 3
3.1	Remove left front cover at cylinder head	To remove the left chain tensioner (1)
			AR01.30-P-5700MBL
3.2	Remove right front cover at cylinder head	To remove the right chain tensioner (1)
			AR01.30-P-5700MBR
4	Remove screw/bolts (3) for chain tensioner (1) and remove chain tensioner (1)	After installation of the chain tensioner (1) the chain tensioner (1) is activated after pulling the securing drift. The chain tensioner (1) moves out and tensions the timing chain. The chain tensioner (1) should be replaced by a new part if this is not the case.
		Screw/bolt, chain tensioner to cylinder crankcase/cylinder head	*BA05.10-P-1001-01R
	Check
5	Check chain tensioner (1) and replace if necessary	The chain tensioner (1) may only now be reset and reused if it did not have any noticeable problems during previous operation and all components of the chain drive do not show any signs of damage or no components of the chain drive were replaced. The chain tensioner (1) is pretensioned by an internal spring and moves out autonomously when being removed. The chain tensioner (1) does not move out on its own: ↓ Replace chain tensioner (1).
6	Reset chain tensioner (1)	When reusing the chain tensioner (1)
			AR05.10-P-7800-03MM
		Chain tensioner for left engine side basic dimension/extended dimension	*BE05.10-P-1001-02A
		Chain tensioner for right engine side basic dimension/extended dimension	*BE05.10-P-1002-02A
7	Install in the reverse order
	Risk of accident  from vehicle starting off by itself when engine running. Risk of injury  (bruises and burns) resulting from working on the engine while it is being started or when it is running.	Secure vehicle to prevent it from starting off by itself. Wear closed and snug-fitting work clothes. Do not touch hot or rotating parts.	AS00.00-Z-0005-01A
8	Carry out an engine test run and check engine for leaktightness

Fig 2: Identifying Socket Wrench Bit (001 589 65 09 00)

Courtesy of MERCEDES-BENZ USA

Fig 3: Identifying Wrench Socket (103 589 02 09 00)

Courtesy of MERCEDES-BENZ USA

Fig 4: Identifying Tie-Down Set (276 589 01 40 00)

Courtesy of MERCEDES-BENZ USA