Remove/Install Chain Tensioner - AR05.10-P-7800MNA

Engine 176 in model 463 

up to model year 2019 

Engine 177 in model 205 

Engine 178 in model 190 

Modification notes 

Shown on model 205 with engine 177 

Courtesy of MERCEDES-BENZ USA

Shown on engine 177 

Fig 1: Primary And Secondary Chain Tensioner Component Location - Model 205 W/ Engine 177

Courtesy of MERCEDES-BENZ USA

	Risk of injury  . Skin or eye injuries may result when handling hot or glowing objects.	Wear protective gloves, protective clothing and safety glasses, if necessary.	AS00.00-Z-0002-01A
	Risk of injury  . Moving parts can pinch, crush or, in extreme cases even sever extremities.	No parts of the body or limbs should be within the operating area of mechanical components when moving components.	AS00.00-Z-0009-01A
	Risk of injury  to skin and eyes due to handling of engine oil. Risk of poisoning  caused by swallowing engine oil	Wear protective gloves, protective clothing and safety glasses. Do not fill engine oil into beverage containers.	AS18.00-Z-0001-01A
	Risk of injury  caused by scraping or cutting body parts on sharp vehicle parts	Always wear protective gloves when working on or near sharp and non-deburred vehicle parts. Deburr repair panels.	AS00.00-Z-0017-01A
Notice	Notes on threaded connections fastened using a tightening angle-based tightening process		AH00.00-P-0020-01A
Notice	Notes on avoiding damage through contamination and foreign objects		AH00.00-P-5000-01A
	Remove/install
1	Remove upper engine cover.	Engine 178 in model 190
		Engine 178 in model 190 with code M032 (Black Series version)	AP01.10-P-2405-01GT
2	Disconnect the ground line for the on-board electrical system battery (G1).	Engine 176 in model 463 (except 463.234) as of model year 2013 up to model year 2019	AR54.10-P-0003GW
		Engine 178 in model 190	AR54.10-P-0003RG
		Engine 177 in model 205	AR54.10-P-0003LW
3.1	Remove left and right air filter housing.	Engine 176 in model 463 up to model year 2019 Engine 177 in model 205	AR09.10-P-1150MNA
3.2	Remove left engine air intake duct downstream of the air filter.	Engine 178 in model 190
4	Remove boot at left exhaust gas turbocharger and place to one side.	Engine 176 in model 463 up to model year 2019
			AR09.10-P-1150MNA
		Clamp, boot to exhaust gas turbocharger/air filter	*BA01.20-P-1003-01J
5	Remove ME-SFI [ME] control unit.	Engine 178.9 in model 190.381	AR07.08-P-7013MNJ
		Engine 178 in model 190 (except 190.381)	AR07.08-P-1000MNB
6	Remove position sensors of camshafts.	Engine 176 in model 463 up to model year 2019	AR15.12-P-2144MNF
		Engine 178 in model 190	AR15.12-P-2144MNB
		Engine 177 in model 205	AR15.12-P-2144MNA
7	Remove tank purge line at right cylinder head cover and press to the side.	Engine 178 in model 190
		Bolt, vent line to cylinder head cover/turbocharger	*BA01.20-P-1001-01J
		Record plug	Fig 3
8	Turn engine at center bolt of the crankshaft through two revolutions, place engine on cylinder 1 at 400 KW after ignition TDC of cylinder 1 and mark with a drift.		AR01.10-P-1000-01SZ
		Only turn engine at the center bolt of the crankshaft in the direction of engine rotation using the specified box wrench. Otherwise, damage to the engine or even failure of the engine may occur.
		Measuring tool	Fig 5
		Ring wrench	Fig 4
		Drift	Fig 2
9	Remove the alternator.	When removing the secondary chain tensioner (2) and the primary chain tensioner (3).
		Engine 176 in model 463 up to model year 2019	AR15.40-P-5032MNF
		Engine 178 in model 190	AR15.40-P-5032MNB
		Engine 177 in model 205	AR15.40-P-5032MNA
10	Unclip electric line at bracket (4).	Engine 176 in model 463 up to model year 2019
11	Unscrew bolts (5) and remove bracket (4).	When removing the secondary chain tensioner (2) and the primary chain tensioner (3). Screw, alternator bracket to crankcase/oil pan	*BA15.40-P-1004-01T
12	Remove circulation pump for low-temperature water circuit and place to one side with connected lines and hoses.	Engine 176 in model 463 up to model year 2019	AR09.41-P-6925MNF
13	Remove clamping device for the poly-V-belt o the alternator.		AR13.20-P-0010MNA
14	Remove drift from belt pulley.	Drift	Fig 2
15	Position engine for removal of secondary chain tensioner (1) or secondary chain tensioner (2) or primary chain tensioner (3) and remove secondary chain tensioner (1) or secondary chain tensioner (2) or primary chain tensioner (3).	The crankshaft may only be turned when the secondary chain tensioner (1), the secondary chain tensioner (2) and the primary chain tensioner (3) are installed. The positions of the crankshaft must be observed. The respective timing chain will skip and engine damage will occur. Replace sealing ring of secondary chain tensioner (1) or secondary chain tensioner (2) and primary chain tensioner (3).	AR05.10-P-7800-06MNA
		Chain tensioner at bottom to crankcase	*BA05.10-P-1001-01V
		Chain tensioner at top to crankcase	*BA05.10-P-1002-01V
		Chain tensioner to cylinder head	*BA05.10-P-1003-01V
		Measuring tool	Fig 5
		Ring wrench	Fig 4
16	Install in the reverse order.
	Concluding tasks
17	Check engine oil level and correct if necessary.
		Engine 176 in model 463.234/239/255 up to model year 2019	AP18.00-P-0101GGE
		Engine 177 in model 205 Engine 178 in model 190	AP18.00-P-1811MP
	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
18	Perform engine test run. While doing so, check engine for proper operation and leak tightness

Fig 2: Identifying Drift (177 589 00 15 00)

Courtesy of MERCEDES-BENZ USA

Fig 3: Identifying Record Plug (129 589 00 91 00)

Courtesy of MERCEDES-BENZ USA

Fig 4: Identifying Ring Wrench (177 589 00 03 00)

Courtesy of MERCEDES-BENZ USA

Fig 5: Identifying Measuring Tool (177 589 01 21 00)

Courtesy of MERCEDES-BENZ USA