1986 TUNE-UP
Mercedes-Benz 6-Cylinder
IDENTIFICATION
ENGINE IDENTIFICATION

First six digits of engine identification number, located on a tag at left rear side of engine crankcase, identify engine.

ENGINE CODE
Application Code
300 E 103.983
TESTING
ENGINE COMPRESSION

Check compression pressure with engine at normal operating temperature, throttle valve fully open and all spark plugs removed. Crank engine at least 8 revolutions per cylinder.

COMPRESSION RATIO
Application Specification
300 E 9.2:1
SPARK PLUGS

SPARK PLUG TYPE
Application Bosch Champion
300 E H7DC S12YC

SPARK PLUG SPECIFICATIONS
Application Gap: In. (mm) Torque: Ft. Lbs. (N.m)
300 E .032 (.80) 15 (20)
HIGH TENSION WIRE RESISTANCE

Carefully remove high tension wires from spark plugs and distributor cap. Using an ohmmeter, check resistance of wires while gently twisting wire. Resistance should be 25,000-30,000 ohms. If resistance is incorrect or fluctuates from infinity to any value, replace wire(s).
ADJUSTMENTS
VALVE CLEARANCE

The valve clearance is compensated for by a hydraulic mechanism located within the rocker arm. No adjustment is required as the rocker arms are continuously in contact with the cam lobes.
VALVE ARRANGEMENT

* Right Side - All Exhaust.
* Left Side - All Intake.

DISTRIBUTOR

All models are equipped with an EZL electronic ignition system. The distributor is a breakerless, transistorized unit. No regular maintenance or adjustments are necessary as timing is controlled by the ignition control module.

Fig. 1: Firing Order & Distributor Rotation
IGNITION TIMING

Check or adjust ignition timing with engine at normal operating temperature, idle speed set to specifications and distributor vacuum lines connected.

IGNITION TIMING (DEGREES BTDC @ RPM)
Application Specification
300 E 6-11 @ 850
IDLE SPEED

All models are equipped with electronic idle speed control. No adjustments are necessary.

IDLE SPEED SPECIFICATIONS
Application Idle RPM
300 E (1)
Engine Cold 830-970
Engine Warm 600
(1) Nonadjustable.
IDLE MIXTURE

NOTE: Mixture is electronically-controlled and cannot be adjusted.
BELT ADJUSTMENT

300 E models are equipped with a serpentine type belt with a self tensioner, no adjustment is required.
IGNITION
Distributor

All models are equipped with an EZL electronic ignition system. The distributor is a breakerless, transistorized unit. No regular maintenance or adjustments are necessary as timing is controlled by the ignition control module.
Ignition Coil

300 E models use Bosch TCI transistorized ignition coil.
SERVICING
EMISSION CONTROL

See EMISSIONS section.
SPECIFICATIONS
FUEL SYSTEM
Fuel Injection

300 E models use Bosch Mechanical/Electrical Continuous Injection System (CIS-E) fuel injection.

FUEL PUMP PERFORMANCE
Pressure: psi (kg/cm 2 ) Volume In 40 Seconds: Pints (Liters)
77-80 (5.3-5.5) .473 (1)
BATTERY

BATTERY SPECIFICATIONS
Application Amp Hr. Rating
300 E 62
STARTER

All models are equipped with Bosch starters. Starter specifications not available from manufacturer.
ALTERNATOR

All models are equipped with Bosch integrally regulated alternators.

ALTERNATOR SPECIFICATIONS
Application Rated Amp Output
300 E 70
ALTERNATOR REGULATOR

All models are equipped with Bosch integral alternator regulators. Regulator operating voltage not available from manufacturer.
SERVICE INTERVALS

REPLACEMENT INTERVALS
Component Interval (Miles)
Air Filter 30,000
Auto. Trans. Fluid 30,000
Fuel Filter 60,000
Oil & Filter 7500
Oxygen Sensor 30,000
Spark Plugs 30,000
CAPACITIES

FLUID CAPACITIES
Application Quantity
Crankcase (Includes Filter) 6.3 Qts. (6.0L)
Cooling System 8.4 Qts. (8.0L)
Auto. Trans. (ATF) 6.5 Qts. (6.2L)
Man. Trans. (ATF) 3.2 Qts. (1.5L)
Rear Axle (SAE 90) 2.3 Pts. (1.1L)
Power Steering (ATF) 1.3 Pts. (.6L)
Fuel Tank 14.5 Gals. (55L)