Mercedes M119DistCapRotor

Introduction: The primary purpose of this page is to illustrate the procedure for replacing the ignition system distributor caps and rotors on the M119.xxx engine. If you have any doubts or are uncertain of your ability to complete these procedures we advise you to seek professional assistance from a qualified technician. We have selected a 1995 E 420 for this project. Other 4-valve 8-cylinder vehicles may utilize similar but not exactly the same steps as described below.

Be advised: MercedesShop accepts no liability for the information contained within this procedure nor for any adverse outcomes as a result of following this procedure. In other words...the risk is 100% YOURS.

Tools needed: 3mm and 5mm allen wrenches or sockets.

Parts needed: two distributor caps (119 158 01 02) and two rotors (119 158 03 31).

Procedure: Begin by parking the car on level ground with the ignition off, the transmission in park and the parking brake engaged. Raise the hood to the full vertical position.

Disassembly: Remove the cover in front of the air cleaner by lifting up.

Remove the left and right air cleaner hoses by pulling away from the air cleaner and then off of the front air scoop.

Remove the left and right suppressor housings by first pulling out and then up on the lower outside edge. The housing should rotate and then release.

Loosen the 3 allen head bolts on each distributor cap using a 5mm allen head socket or wrench. Remove the cap and disconnect the wires.

Inspect the inside of each distributor cap. This cap clearly needs to be replaced due to carbon tracking and corrosion caused by moisture. Note the greenish deposits to the right of the contacts.

Loosen the 3 allen head bolts on each rotor using a 3mm allen head socket or wrench. Remove the rotors.

Inspect the contact tips on each rotor. Note the condition of the contact surface. Here a considerable portion of the surface has been burned away.

Reassembly: Install the new rotors and tighten the 3mm allen head bolts. The rotors will only install one way so you cannot do it incorrectly.

Note that each distributor cap is marked to indicate which ignition wire goes where. The top connector for example is marked R4 and L5. This means that when this cap is installed on the right side of the engine*, wire number 4 should be attached to the top connector. When this cap is installed on the left side of the engine, wire number 5 would be attached to the top connector.

Install the new distributor caps with the R4/L5 connector positioned at the top. Tighten the 5mm allen head bolts.

*Note- The right side of the engine is the side that would be on your right if you were sitting in the car. The right side of the engine is on your left if you are in front of the car facing the engine.

Here's a helpful hint...

Before connecting the wires to the new distributor cap, place the old cap on top of the air cleaner and orient it with the R4/L5 connector away from you. This way you can use the old cap as a map or template when connecting the wires to the new cap

Secure each wire to the correct connector on the distributor caps. Be sure that the numbers on each wire correctly match the numbers on the connector. Also make sure that the wires are neatly "dressed" so that there will be no interference with the suppressor housing.

Reinstall the suppressor housings by first inserting the tab nearest the centerline of the engine and then rotating down on the outside of the housing. Press down firmly on the outside of the housing until you hear the "click" of the outside fastener engaging.

Reinstall the air cleaner hoses and the front cover.

Start the engine. The engine should start normally and idle smoothly. If not, immediately turn off the engine and recheck the installation of the distributor caps and wires.

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