Replace Spark Plugs - AP15.10-P-1580J

Engine 139 in model 118, 177, 247

Shown on engine 139 in model 177.053

Courtesy of MERCEDES-BENZ USA

Shown on engine 139 in model 177.053

Courtesy of MERCEDES-BENZ USA

Shown on ignition coil in engine 157.980

Courtesy of MERCEDES-BENZ USA

	Risk of death when working on component parts and systems with U >= 30 V alternating voltage (AC) or U >= 60 V direct voltage (DC)	Do not touch damaged or defective live component parts and lines or non-insulated electrical connections and lines.	AS00.00-Z-0035-01A
	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
Notice	Information on avoiding damage when replacing spark plugs		AH15.10-P-0002-02A
Notice	Notes on avoiding damage to ignition system		AH15.10-P-0002-01V
	Preparatory tasks
1	As a supplement to the following description, the method can also be called up as a WSM film.	Video: Clean spark plug wells	multimedia:A supplement to the article is available.
	Remove
2	Switch electronic ignition lock control unit to position "0".
3	Remove engine cover.		AP01.10-P-2405-01K
4	Remove bolts (5).
5	Remove ignition coils (6a, 6b, 6c, 6d) with lines connected and place to one side.	Do not crush or kink or subject electric lines to tension. Damage can otherwise occur.
	Clean
6	Use compressed air to blow out any dirt residue in the spark-plug recesses.	Seal openings with lint-free rags. Damage can otherwise occur. Record plug	Fig 2
	Check
7	Check whether dirt remains in the spark plug wells.	If dirt remains in the spark plug wells, ↓ clean spark plug wells with cleaner and blow out with compressed air. Continue with operation step 8. If the spark plug wells are clean, ↓ Proceed with operation step 10.
	Clean
8	clean spark plug wells with cleaner and blow out with compressed air.	If dirt remains in the spark plug wells. Seal openings with lint-free rags. Damage can otherwise occur.
	Check
9	Check whether dirt remains in the spark plug wells after cleaning with cleaner.	If dirt remains in the spark plug wells. If dirt remains in the spark plug wells, ↓ clean spark plug wells with cleaner and blow out with compressed air. Continue with operation step 8. If the spark plug wells are clean, ↓ Proceed with operation step 10.
	Remove
10	Unscrew spark plugs (1) using spark plug wrench (01) from cylinder head.	Spark plug wrench	Fig 1
	Clean
11	Vacuum spark plug wells using vacuum cleaner attachment.	Remove metal insert at end of hose. Damage can otherwise occur. Adapter	Fig 3
	Install
12	Screw new spark plugs (1) using spark plug wrench (01) into cylinder head.	Spark plug to cylinder head	*BA15.10-P-1001-01E
		Spark plug wrench	Fig 1
	Check
13	Check spark plug connectors (2), ignition coils (6a, 6b, 6c, 6d) and ignition lines for damage, deformation and cracking.	If problems are determined, ↓ rectify the problems. After obtaining special order.
	Install
14	Apply coating of spark plug connector grease to sealing lips (3) of spark plug connectors (2) before installation.	Spark plug connector grease 35 g	*BR00.45-Z-1102-06A
15	Install ignition coils (6a, 6b, 6c, 6d) with lines connected.
16	Screw in screws (5).	Screw/bolt, ignition coil to cylinder head cover	*BA15.10-P-1001-04A
	Check
	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
17	Perform engine test run.	If problems are determined, ↓ rectify the problems. After obtaining special order.
18	Switch off engine.
	Install
19	Install engine cover.		AP01.10-P-2405-01K