MERCEDES-BENZ 420SEL REPAIR MANUAL -- HOW TO FIX YOUR CAR OR TRUCK

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MERCEDES-BENZ 420SEL CAR/TRUCK REPAIR PROCEDURES AND DIAGRAMS - WHAT MERCEDES-BENZ REPAIR SHOPS DON'T WANT YOU TO KNOW

Learn how to repair a car or truck, install or remove parts, wire an engine, reset warning lights, replace fuel filter, fix auto body and more. Get Automotix DIY!

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1991199019891988
19871986

Get Full Access Automotix DIY provides automotive consumers and do it yourselfers; the most comprehensive repair information about MERCEDES-BENZ 420SEL car and truck repair procedures including MERCEDES-BENZ engine diagrams, wiring diagrams, repair work estimating measures, technical service bulletins, auto body work guidance, starter & alternator replacement procedures, serpentine belt replacement procedures, radiator & hose replacement procedures, tune-up & drivability specifications, quick lube illustrations, preventive maintenance guide, engine light reset instructions, parts removal and install procedures, fuel filter replacement directions, component location diagrams, air filter locations & replacement instructions, a/c system specifications, and general auto service procedures. You don't have to be a car mechanic or technician to know how to fix your MERCEDES-BENZ 420SEL automobile. Try the Automotix DIY solution today!
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Using the Automotix DIY repair procedures will save you hundreds and even thousands of dollars! In addition, it will save you hours of touring the city searching for MERCEDES-BENZ mechanics you can trust. The Automotix DIY solution is particularly affordable. A full access to the entire DIY repair procedures and diagrams for your MERCEDES-BENZ 420SEL vehicle will cost less than a single gallon of gas. Here are some of the DIY repair tips and procedures you will find here:

A/C & HEATER SERVICE PROCEDURES FOR MERCEDES-BENZ 420SEL AUTOMOBILES

Air Conditioner and Heater Service Includes module configuration procedures, general service, maintenance, automatic temperature control, compressor services, electric cooling fans, vacuum diagrams, specifications, and manual air conditioning and heater diagnostics and replacement procedures for domestic and imported MERCEDES-BENZ 420SEL cars and light trucks from 1990+

Imported Cars & Light Trucks & Vans -> 1991-92 -> Precautions -> Cleanliness -> General Service -> Safety
Vehicle: 1991 MERCEDES-BENZ 420SEL 4.2 V8 GAS

Safety

The Freon refrigerant used in car air conditioners is also known as R-12. It is colorless and odorless both as a gas and a liquid. Since it boils (vaporizes) at -21.7°F, it will usually be in a vapor state when being handled in a repair shop. But if a portion of the liquid coolant should come in contact with the hands or face, note that its temperature momentarily will be at least 22° below zero.

Protective goggles should be worn when opening any refrigerant lines. If liquid coolant does touch the eyes, bathe the eyes quickly in cold water. Then apply a bland ...

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BRAKE SERVICE PROCEDURES FOR MERCEDES-BENZ 420SEL AUTOMOBILES

Includes anti-lock brakes, disc, drum, power and hydraulic brake services diagnostics and procedures for domestic and imported MERCEDES-BENZ 420SEL cars and light trucks from 1990+.

MERCEDES-BENZ -> PARKING BRAKE ADJUSTMENT -> 190D & E, 260E, 300CE, D, E & TE -> 300SE & SEL, 420SEL, 560SEC, SEL & SL
Vehicle: 1991 MERCEDES-BENZ 420SEL 4.2 V8 GAS

300SE & SEL, 420SEL, 560SEC, SEL & SL

  • Loosen each LH and RH shouldered bolt from rear axle.
  • Raise and support vehicle.
  • Rotate wheel until threaded hole, from which the shouldered bolt has been removed, faces forward and up at about a 45° angle on models with diagonal swing axle and exactly forward on models with diagonal swing axle and starting torque compensation.
  • Insert suitable screwdriver through hole of wheel rim brake disc and rear axle shaft flange. Engage screwdriver with adjustment star and turn adjusting star until star can no longer be turned. Turn back adjusting...

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FUEL FILTER REPLACEMENT PROCEDURES FOR MERCEDES-BENZ 420SEL AUTOMOBILES

Fuel filter replacement procedures with corresponding images for most domestic and imported MERCEDES-BENZ 420SEL cars and light trucks sold in the U.S. for 1980+.

Mercedes-Benz -> Fuel Filter Replacement -> Except 2003-06 E320 & E500 Sedans Less 4 Matic & 2004-06 E Series w/Gasoline Engines -> Fuel System Pressure Relief -> Removal & Installation
Vehicle: 1991 MERCEDES-BENZ 420SEL 4.2 V8 GAS

Fuel System Pressure Relief

Do not smoke or allow an open flame of any type when working on or near any fuel system related components. The highly flammable vapor mixtures may ignite, resulting in serious personal injury.

Prior to disconnecting fuel lines, the fuel system pressure must be relieved to prevent accidental fuel spray.

After the battery has been disconnected and reconnected, some abnormal driveability symptoms may occur. The vehicle may need to be driven while it relearns its adaptive strategy.

  • Ensure t...

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DRIVELINE, U-JOINT & CV AXLES REPLACEMENT PROCEDURES FOR MERCEDES-BENZ 420SEL AUTOMOBILES

Includes CV axle, universal joint, and driveline replacement, for domestic and imported MERCEDES-BENZ 420SEL cars and light trucks from 1990+.

CV AXLE SHAFT, Replace
Vehicle: 1990 MERCEDES-BENZ 420SEL 4.2 V8 GAS

  • Raise and support vehicle, then remove wheel, Fig. .
  • Remove front axle shaft attaching collar nut.
  • Remove lower engine compartment cover.
  • Using suitable socket, remove axle shaft from connecting flange.
  • Using suitable wire, secure inner joint in compressed piston.
  • Position steering wheel to right stop.
  • Using suitable plastic hammer, loosen fron...

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STARTER & ALTERNATOR REPLACEMENT PROCEDURES FOR MERCEDES-BENZ 420SEL AUTOMOBILES

Includes starter and alternator replacement procedures for domestic and imported MERCEDES-BENZ 420SEL cars and light trucks from 1990+.

Starter, Replace
Vehicle: 1991 MERCEDES-BENZ 420SEL 4.2 V8 GAS

  • Disconnect battery ground cable from battery.
  • Remove electrical connections from...

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MAINTENANCE LAMP RESET PROCEDURES FOR MERCEDES-BENZ 420SEL AUTOMOBILES

Maintenance lamp reset procedures with corresponding images for most domestic and imported MERCEDES-BENZ 420SEL cars and light trucks sold in the U.S. from 1990+.

Mercedes-Benz -> Brake Pad Wear Indicator Lamp ->
Vehicle: 1991 MERCEDES-BENZ 420SEL 4.2 V8 GAS

The Brake Pad Wear indicator lamp should illuminate when the ignition switch is placed in the On position to indicate the warning lamp is operational. After the engine has been started, the warnin...

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RADIATOR & HOSE REPLACEMENT PROCEDURES FOR MERCEDES-BENZ 420SEL AUTOMOBILES

Includes radiator, cooling and heater hose replacement procedures for domestic and imported MERCEDES-BENZ 420SEL cars and light trucks from 1990+

Radiator, Replace
Vehicle: 1990 MERCEDES-BENZ 420SEL 4.2 V8 GAS

  • Remove bottom engine compartment panel.
  • Drain coolant into a suitable container.
  • On models with automatic transmission, remove transmission oil cooler lines.
  • On all models, remove coolant hoses from radiator.
  • Remove coolant overflow...

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SERPENTINE BELT SERVICE PROCEDURES FOR MERCEDES-BENZ 420SEL AUTOMOBILES

Serpentine belt replacement procedures with corresponding images for most domestic and imported MERCEDES-BENZ 420SEL cars and light trucks sold in the U.S. from 1990+.

Serpentine Drive Belt, Replace
Vehicle: 1991 MERCEDES-BENZ 420SEL 4.2 V8 GAS

  • On models equipped with viscous fan clutch, remove union nut by turning nut counterclockwise.
  • On models equipped with electric fan, disconnect electrical connector at engine and air conditioning fan.
  • Remove retaining pin on right and left side.
  • Press together retainer clamp of radiator on right and left and release radiator bridge.
  • Press clamps on right and left at sa...

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COMPONENT LOCATION DIAGRAMS FOR MERCEDES-BENZ 420SEL AUTOMOBILES

Component location diagrams for most MERCEDES-BENZ 420SEL cars and light trucks sold in the U.S. from 1990+.

Top Front Of Engine Diagram for 1991 MERCEDES-BENZ 420SEL  4.2 V8 GASTop Front Of Engine Diagram for 1991 MERCEDES-BENZ 420SEL 4.2 V8 GAS

Components on diagram:
  • Coolant Temperature Gauge Sensor
  • Idle Speed Air Valve
  • Top Of Engine Diagram for 1989 MERCEDES-BENZ 420SEL  4.2 V8 GASTop Of Engine Diagram for 1989 MERCEDES-BENZ 420SEL 4.2 V8 GAS

    Components on diagram:
  • Electro-Hydraulic Actuator
  • CLICK HERE TO GET FULL ACCESS TO MERCEDES-BENZ 420SEL PARTS/COMPONENTS LOCATION DIAGRAMS!

    WIRING DIAGRAMS FOR MERCEDES-BENZ 420SEL AUTOMOBILES

    OEM drawn wiring diagrams for most MERCEDES-BENZ 420SEL cars and light trucks sold in the U.S.

    1990 MERCEDES-BENZ 420SEL  4.2 V8 GAS Wiring Diagram1990 MERCEDES-BENZ 420SEL 4.2 V8 GAS Wiring Diagram

    Components on diagram:
  • Radio
  • LH Rear Speaker
  • LH Front Speaker
  • RH Rear Speaker
  • RH Front Speaker
  • 1990 MERCEDES-BENZ 420SEL  4.2 V8 GAS Wiring Diagram1990 MERCEDES-BENZ 420SEL 4.2 V8 GAS Wiring Diagram

    Components on diagram:
  • RH Rear Seat Heater Switch
  • LH Rear Seat Heater Switch
  • LH Rear Bench Back Adjustable Switch
  • Rear Seat Heater Control Unit
  • RH Rear Bench Back Adjustable Switch
  • CLICK HERE TO GET FULL ACCESS TO MERCEDES-BENZ 420SEL WIRING DIAGRAMS!

    TECHNICAL SERVICE BULLETINS FOR MERCEDES-BENZ 420SEL AUTOMOBILES

    OEM TSB listings for most MERCEDES-BENZ 420SEL cars and light trucks sold in the U.S. from 1985+.

    Document: TECHNICAL INFORMATION UPDATE ANNOUNCEMENT - FACTORY APPROVED SERVICE PRODUCTS
    Vehicle: 1990 MERCEDES-BENZ 420SEL 4.2 V8 GAS

    Auto Systems:
  • Labor Times, Manuals, Warranty, Aids
  • Document: MBUSA APPROVED REFINISHING PRODUCTS
    Vehicle: 1988 MERCEDES-BENZ 420SEL 4.2 V8 GAS

    Auto Systems:
  • Finishes, Body Structure, Frame, Bumpers
  • CLICK HERE TO GET FULL ACCESS TO MERCEDES-BENZ 420SEL TECHNICAL SERVICE BULLETINS!

    COMPONENT/PARTS SPECIFICATIONS FOR MERCEDES-BENZ 420SEL AUTOMOBILES

    BRAKE SPECIFICATIONS: Brake drum, rotor, caliper, and related specifications for most MERCEDES-BENZ 420SEL cars and light trucks sold in the U.S. and Canada from 1970+.

    • Brake caliper mounting bolt torque
    • Brake drum runout, machining, & discard specs
    • Minimum brake lining thickness.
    • Brake rotor runout, parallelism, machining, discard, & finish specs

    A/C SYSTEM SPECIFICATIONS: Air conditioning refrigerant capacity and type as well as lubricant capacity for most MERCEDES-BENZ 420SEL cars and light trucks sold in the U.S. and Canada from 1980+.

    • Refrigerant capacity & type, compressor oil viscosity, total system oil capacity & compressor clutch gap

    COOLING SYSTEM BLEED: Cooling system bleeder valve identification, bleeder type and bleed procedures for most domestic and imported cars and light trucks sold in the U.S. and Canada from 1986+.

    PREVENTIVE MAINTENANCE: Preventive maintenance recommendations and required services for most domestic and imported cars and light trucks sold in the U.S. and Canada from 1980+. Includes severe and routine service schedules

    QUICK-LUBE and ILLUSTRATIONS: Fluid recommendations, capacities, drain plug torques, tire data, and severe service recommended preventive maintenance schedules. Information covers most MERCEDES-BENZ 420SEL cars and light trucks sold in the U.S. and Canada from 1980+. Engine and chassis service images.

    • Automatic transmission/transaxles capacities, lubricant recommendations
    • Differential/final drive capacities, lube recommendations, grades, & viscosities
    • Final drive fill & drain plug torques
    • Number of lubrication fittings & plugs
    • Power steering, brake, & clutch fluid recommendations
    • Manual transmission/transaxle capacities, lube recommendations, grades, & viscosities
    • Number of lubrication fittings & plugs
    • Power steering, brake, & clutch fluid recommendations
    • Engine oil capacities, API grade recommendations, SAE viscosity recommendations, drain plug torque
    • Severe service maintenance & interval recommendations
    • Tire sizes, wheel nut/bolt torque, pressures & rim sizes
    • Transfer case capacities, lube recommendations, grades, & viscosities

    TUNE-UP & DRIVEABILITY SPECIFICATIONS: Most tune-up specifications for most MERCEDES-BENZ 420SEL cars and light trucks sold in the U.S. and Canada from 1980+

    • Airflow sensor electrical specifications
    • Tensioning specifications for systems with automatic tensioners
    • Barometric pressure sensor specs
    • Battery group number and cranking performance
    • Crankshaft & camshaft position sensor resistance
    • Engine compression pressures
    • Coolant temperature sensor specs
    • Computer advance.
    • Diesel fuel temperature sensor resistance.
    • Distributor advance specifications
    • Ignition pickup coil resistance
    • Exhaust gas recirculation temperature sensor resistance
    • Engine fastener torque values
    • Firing order diagrams
    • Fuel system pressures
    • Generator (alternator) specs
    • Intake air temperature sensor specs
    • Ignition coil specifications
    • Fuel injector resistance
    • Engine idle speeds
    • Knock sensor resistance
    • Manifold absolute pressure sensor specs
    • Mixture control solenoid resistance
    • Voltage regulator specs
    • Spark plug applications & gaps
    • Starter motor electrical specs.
    • Tensioning specifications for systems without automatic tensioners
    • Throttle body temperature sensor resistance
    • Ignition timing in degrees at rpm
    • Transmission oil temperature sensor resistance
    • Throttle position sensor specs
    • Vacuum sensor valve specs

    CLICK HERE TO GET FULL ACCESS TO MERCEDES-BENZ 420SEL SPECIFICATIONS DATA!

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    Click here to view more details about 1991 Mercedes Benz 420SEL Splash Shield, Passenger Side, Front1991 Mercedes Benz 420SEL Splash Shield, Passenger Side, Front, A High Quality, Direct Fit OE Replacement For Splash Shield.

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    Click here to view more details about 1991 Mercedes Benz 420SEL Radiator1991 Mercedes Benz 420SEL Radiator, 16.87 x 26.25 x 1.62 in. core size, 2.5 x 27.38 in. top header, 2.5 x 27.38 in. bottom header, plastic tanks, top right inlet location, bottom right outlet location; With transmission oil cooler; Without engine oil cooler; A high quality, direct fit OE replacement radiator..

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