1986 Mercedes-Benz 300E Service Manual (PN 126-589-10–21-00)

• Covers the 1986 Mercedes-Benz 300E, chassis type 124.030, with the 3.0L six-cylinder engine identified by code 103.983. The repair information set is keyed to this 1986 300E; references to 260E, 300CE, 300TE, 190, 420, and 560 models occur inside shared application tables or multi-model system articles and should not be read as full vehicle coverage for those models.
• Supplied as 68 PDF articles totaling 1,063 pages, carrying Mitchell Repair Information Company copyright 1998. Coverage spans engine repair, Bosch CIS-E/EZL controls, W4A040 automatic-transmission diagnosis, drive axle, brakes and ABS, steering and suspension, automatic A/C-heater, SRS, maintenance data, electrical component locations, and vehicle wiring.
• Includes shop-level procedures that owners commonly send to a repair shop: engine/transmission removal, cylinder-head service, timing-chain replacement, camshaft timing checks, valve-guide work, CIS-E fuel-pressure diagnosis, ABS testing, brake-caliper overhaul, front spring/strut work, rear suspension and axle removal, A/C evaporator/heater-core service, and wheel alignment.
• Concrete specifications include a 6.3 qt (6.0 L) engine oil-and-filter fill, 7.1 psi oil pressure at 700–780 RPM and 42 psi at 3000 RPM, 76.9–79.8 psi CIS-E system pressure, a 6.6 qt (6.2 L) automatic-transmission capacity, and a 9.5 qt (9.0 L) 1986–87 cooling-system capacity.

Engine and Mechanical Repair

The 3.0L engine article goes well beyond tune-up data. It covers engine and transmission removal as an assembly, cylinder-head removal and installation, timing chain and sprockets, camshaft timing, rocker arms and hydraulic compensating valves, valve springs, seals and guides, piston/rod assemblies, crankshaft and bearings, engine oiling, the oil pump, and water pump. Tables provide piston, ring, bearing, valve, spring, camshaft, and torque specifications; the crankshaft damper bolt is specified at 221 ft-lb (300 N·m).

Special-service equipment is identified where the work depends on it, including Guide Sleeve 103 589 00 14 00, Assembly Fixture 102 589 00 59 00, Supporting Bridge 102 589 01 59 00, and dedicated intake/exhaust valve-guide mandrels. One repair trap is explicit: with the cylinder head still on the engine, the valve spring procedure requires the cylinder to be held with compressed air to avoid valve damage. The front timing-cover procedure also calls out protecting the oil-pan gasket during installation.

Fuel Injection, Transmission, Brakes, and Chassis

Bosch CIS-E coverage includes the airflow-sensor plate and potentiometer, electro-hydraulic actuator/differential-pressure regulator, coolant sensor, ECU, idle-speed controls, oxygen sensor, lambda control, fuel-pump relay, and EZL electronic ignition. Diagnosis is built around measured values rather than symptom descriptions alone. The manual specifies 76.9–79.8 psi system pressure, lower-chamber pressure about 5.8 psi below system pressure under defined conditions, and fuel-pump delivery of 1 liter in 50 seconds at 11.5 volts. It also identifies the Bosch KDJE-P600 On-Off Ratio Tester, Fuel Pressure Gauge 100 589 00 21 00, and related test adapters.

For the 1986 300 Series, the automatic-transmission diagnosis article identifies the W4A040 family and explains the two compound planetary gear sets, clutches K-1/K-2, brake bands B-1/B-2, disc brake B-3, primary/secondary pumps, valve body, and pressure-control circuits. A separate A/T removal-and-installation article is included. The diagnostic article directs vacuum-control, hydraulic-pressure, and road-test procedures to a separate “Auto Trans Overhaul - W4A020 & W4A040” article, so this PDF bundle does not present that referenced full overhaul/testing section.

Brake coverage includes four-wheel disc brakes, caliper service, bleeding, parking-brake adjustment, and Bosch three-channel ABS diagnosis. The ABS article specifies Test Adapter 126-589-09-21-00 and electrical checks for front and rear speed sensors, solenoid valves, relays, and the hydraulic unit. It also warns not to hammer ABS speed-sensor rings because impact can demagnetize them and corrupt wheel-speed signals. During caliper repair, chrome-plated piston surfaces must not be cleaned with emery or polishing cloth because the surface can be damaged.

Climate Control, Electrical, and Diagnostic References

Automatic climate-control coverage includes the push-button control panel, in-car and heater temperature sensors, heater valve, ECU, blower-speed controller, switchover valves, air doors, expansion valve, auxiliary fan, and evaporator temperature regulator. The ETR switch stops compressor operation below approximately 36°F (2°C) evaporator temperature. Most importantly for 1986 cars, the manual separates the vacuum routing into “Vacuum Diagram - 300E (Up To August 1986)” and “Vacuum Diagram - 300E (As of September 1986),” making the production change visible before diagnosis or hose routing is attempted.

Named diagrams and views include “Wiring Diagram For 300E CIS-E Fuel Injection System,” “ABS System Wiring Diagram (300 & 260 Series),” “Cooling Fan Circuit,” “Charging Circuit,” “Vacuum Diagram - 300E (Up To August 1986),” and “Vacuum Diagram - 300E (As of September 1986).” Separate electrical-component locator and wiring articles cover the fuse block, under-dash areas, instrument panel, rear compartment, starting/charging, exterior lighting, power windows, power seats, locks, mirrors, wiper/washer, and related circuits.

For SRS-equipped cars, the air-bag section covers system disabling/activation, component testing, inspection, and disposal procedures and identifies SRS Tester 126-589-10-21-00. Work involving SRS, loaded coil springs, pressurized fuel or brake systems, hot cooling-system components, or A/C refrigerant should follow the isolation, support, depressurization, and handling precautions stated in the relevant article.