1991 HONDA CIVIC engine coolant

Evaporative Emission Control System
The Evaporative Emission Control System is designed to prevent
fuel vapors from escaping into the atmosphere. Fuel vapors from the fuel tank are directed into the charcoal
canister where they are adsorbed and stored while the engine is stopped or idling. When the coolant temperature rises to a certain
value, the vapors are drawn into the engine through the throttlebody and the intake manifold during normal engine operation.
Engine Exhaust Emission Controls
The engine exhaust emission control systems are designed to control combustion during idle, acceleration, cruise, and deceleration.
These systems are entirely separate from the crankcase and evaporative emission control systems described previously.
HONDA PGM-FI System
The PGM-FI system consists of three independent sub-systems; Air Intake, Electronic Control and Fuel Control, thus allowing moreaccurate control of air/fuel ratios under all operating conditions.
The Electronic Control Unit (ECU) detects the amount of air
drawn into the cylinders and determines the amount of fuel to be injected to provide the optimum air/fuel ratio for all engine needs.
Ignition Timing Control System
This system automatically controls the ignition timing to reduce
the amount of HC and NOx.
Catalytic Converter
Three Way Catalyst
The catalyst is used to convert hydrocarbons (HC), carbon monoxide (CO) and oxides of nitrogen (NOx) in the exhaust gas,

to carbon dioxide (CO 2
), dinitrogen (N 2
) and water vapor.

Exhaust Gas Recirculation (EGR) (California automatic models except EX Sedan)
The EGR system is designed to control the formation of oxides of nitrogen (NOx) caused when fuel mixture burns at high
temperature. It works by recirculating exhaust gas through the EGR valve and intake manifold into the combustion chambers
where it reduces peak temperature by diluting the air/fuel mixture.ProCarManuals.comMain Menu s t

Index

Battery
Charging System Warning Light.............................................. 30
Jump Starting ........................ 110
Maintenance............................. 89
Specification (Hatchback).... 116
Specification (Sedan)............ 119
Beeper System Fasten Seat Belt Beeper(Sedan).................................. 11

(Hatcback)............................ 15

Belts, Seat............. See "Seat Belts"
Body Repair.................................. 102
Brake Warning Light...................... 31 Brakes
Brake Failure Warning Light.... 31

Brake Fluid................................ 84

Brake System Design.............. 83
Brake Wear Indicators............. 84
Parking Brake........................... 42
Parking Brake Warning Light.. 31
Break-in Period................................. 2

Bulb
Replacement............................
92

Specification (Hatchback)....
117
Specification (Sedan)............

120
Buzzer........... See
"Beeper System"
Capacities (Hatchback)............... 115 Capacities (Sedan)....................... 118
Care and Cleaning.......................... 99
Catalytic Converter..................... 126 Certification Label....................... 121
Chains, Tires...................................

95
Check Engine
Warning Light......... 31
Child Proof Door Locks...................

5

Child Restraint
System................. 21
Cigarette Lighter............................ 44

Clock............................................... 42
Clutch Pedal Adjustment.............. 61
Compact Spare Tire.................... 104
Coolant Temperature Gauge ........

28
Cooling (with
A/C).........................

49

Cooling System..............................

80

Crankcase Emission Control
System................................... 124
Cruise Control Operation.................................. 39
Indicator.................................... 31

Defogger........................................ 34
Defroster........................................ 51

Doors
Child Proof Door Locks............. 5

Locks........................................... 3

Power Locks.............................. 4

Emergency
Changing a Flat Tire............... 105
Hazard Warning System ......... 37If Your Car Gets Stuck.......... 112
Jump Starting........................ 110

Shoulder Belt Buckle............. 113

Towing.................................... 111
Warning and Indicator Lights.. 29
Emission Controls........................ 124

Engine
Coolant...................................... 80

Coolant Temperature Gauge... 28
Exhaust Controls................... 125Identification Number............ 12

1
Oil and
Filter.............................. 76
OH Pressure Warning Light..... 30
Specification (Hatchback).... 116
Air Conditioner
Operation.................................. 47

Service...................................... 98

Air Filter.......................................... 86

Air Pressure, Tires......................... 94
Antifreeze.. See "Radiator Coolant" Anti-theft Steering Column Lock System ..................................... 57
Appearance Care........................ 100

Ashtrays......................................... 44

Automatic Seat Belt...................... 10

Automatic Transmission
Driving Technique.................... 66

Fluid........................................... 79

Operation.................................. 64

(cont'd)ProCarManuals.comMain Menu s t

Maintenance
Non-Scheduled MaintenanceRecord................................... 72
Scheduled Maintenance Record................................... 71

Schedule................................... 68

Severe Driving Conditions...... 72
Manual Transmission Clutch Pedal Adjustment........ 61
Maximum Allowable Speeds.. 63
Oil...............................................
78

Recommended Shift
Speeds.. 62

Shifting......................................

61

Meters, Gauges..........
See "Gauges"
Mirrors Power Mirrors.......................... 35

Rearview Mirrors..................... 35

Octane Rating, Gasoline. See "Fuel"
Odometer........................................ 28
Oil
Engine Oil.................................. 75

Fluid Locations......................... 74
Oil Pressure Warning Light..... 30
Power Steering Fluid................ 85
Transmission Oil/Fluid.............. 78
Operation In Foreign Countries..... 55
Panel Brightness Control............... 37
Parking Brake................................. 42
Passive Belt.................................... 10
PGM-FI
System.................................... 125
Power Door Locks................................. 4
Mirrors...................................... 35
Steering..................................... 85

Windows.................................. 43

Pregnant Women........................... 25
Pressures, Tire Inflation................ 94
Preventive Service...................... 102 Radiator Coolant............................ 80

Rear Seat.......................................... 8

Rearview Mirrors........................... 35
Rear Window Defogger................ 34Rear Window Wiper...................... 34Reminder Lights .................. See "Warning Lights"
Replacement
Air Filter.................................... 86

Bulb............................................ 92
Engine Oil.................................. 76

Fuel Filter.................................. 86

Fuse...........................................90
Oil Filter..................................... 76
Radiator Coolant...................... 82
Spark Plugs............................... 87

Tire............................................ 94
Wiper Blades............................. 88
Rust Prevention........................... 101
Safety Defects, Reporting.......... 128

Safety Items................................... 59

Seats
Adjustment................................. 6
Head Restraints.......................... 7
Seat Belt Reminder Light
and Beeper (Sedan).................. 14

Seat Belt Reminder Light and Beeper (Hatchback).......... 17
Seat Belts Anchor Points (Hatchback)..... 22
Anchor Points (Sedan)............ 24

Automatic Belt......................... 10

Buckling the Front Seat Belts (Sedan)............... 11
Buckling the Front Seat Belts (Hatchback)....... 15
Buckling the Rear Seat Belts .. 19
Child Restraint.......................... 21
Cleaning..................................... 25

Fasten Seat Belt Reminder Light and Beeper (Sedan).............. 14
Fasten Seat Belt Reminder Light and Beeper (Hatchback)...... 17

(cont'd)

Numbers, Identification............... 121ProCarManuals.comMain Menu s t

Index (cont'd)

Inspection................................. 25

Passive Belt.............................. 10
Pregnant Women..................... 25
Rear Center Seat Belt.............. 20
Replacement............................. 25 Shoulder Belt Buckle............. 113

Seats
Front Seat................................... 6
Head Restraints.......................... 7

Rear Seat.................................... 8

Shifting
Automatic................................ 64

Manual....................................... 61

Spare Tire Changing a Flat Tire............... 106
COMPACT Spara Tire........... 104
Spark Plugs Replacement............................. 87
Specifications (Hatchback) ..116Specifications (Sedan).......... 119
Speedometer.................................. 28
Starting the Engine......................... 58
Steering Anti-theft Column Lock .......... 57Power Steering......................... 85

Tilt Steering.............................. 32

Stuck Car..................................... 112

Sunroof........................................... 52
If the Sunroof Won't Close..... 53
Maintenance............................. 53
Operation.................................. 52

Sunshade.................................. 52

Tachometer.................................... 28
Temperature Gauge, Coolant....... 28 Tilt Steering.................................... 32
Tire Air Pressure............................. 94
Balancing................................... 97

Chains....................................... 95

Changing a Flat Tire............... 106COMPACT Spare.................. 104
DOT Tire Quality Grades....... 122
Inflation Pressures................... 94 Requirement............................. 96
Rotation.................................... 97
Snow Tire................................. 95
Spare Tire............................... 104
Specification (Hatchback).... 116 Specification (Sedan)............ 119
Tools............................................. 105
Towing.......................................... 111

Transmission
Capacity.................................... 79
Identification Number............ 121

Oil/Fluid..................................... 78

Shifting the Automatic............ 64

Shifting the Manual.................. 61
Transmission............................ 78
Treadwear.................................... 122

Trip Meter....................................... 28
Trunk Access From Rear Seat....... 8

Trunk Lid........................................... 5

Turn Signals.................................... 36
Warning Lights............................... 29
Warranty Service........................ 127Washer Rear Window Washer............. 34Reservoir Capacity.................. 33
Windshield Washer.................. 33
Washing........................................ 100

Waxing......................................... 101

Windows
Appearance Care................... 100
Power Windows...................... 43

Windshield Defogger..................... 51 Windshield Washer....................... 33
Windshield Wipers........................ 33
Wiper Blades ..................................
88
Wipers Rear Windo
w Wiper................ 34
Windshield Wipers................... 33
Vehicle Identification Number.... 121
Ventilation...................................... 45ProCarManuals.comMain Menu s t