For 1990-2009 cars

Perform the following checks and services at the specified intervals. This will help ensure the safety, dependability, and emission control of the vehicle.

Important: Inspect any safety-related components that may have been damaged in an accident. Complete any necessary repairs before operating the vehicle.

At the minimum, perform these routine inspections every 6 months or 10 000 km (6,000 mi), whichever occurs first. Complete any necessary repairs before operating the vehicle.

### At Each Fuel Fill

Important: Perform these underhood inspections at each fuel fill.

#### Engine Oil Level Inspection

Inspect the engine oil level. Add the proper oil if necessary.

#### Engine Coolant Level Inspection

Inspect the engine coolant level. Add the proper coolant mix if necessary.

#### Windshield Washer Fluid Level Inspection

Inspect the windshield washer fluid level in the windshield washer tank. Add the proper fluid if necessary.

#### Tire Inflation Inspection

Inspect the cold tire inflation. Ensure that the tires are inflated to the pressures specified on the Certification/Tire label. Refer to Vehicle Certification Label in General Information for an explanation of the label.

### At Least Twice a Year

#### Restraint System Inspection

Ensure that the following components are functioning properly:

• | The belts

• | The buckles

• | The latch plates

• | The retractors

• | The anchorages

• | The reminder systems

Inspect for any other loose or damaged safety belt system parts.

Repair any components or condition that might prevent a safety belt system from functioning properly.

Replace any torn or frayed safety belts.

#### Wiper Blade Inspection

Inspect the wiper blades for wear or cracking. Replace worn or damaged blade inserts. Replace any blade inserts that streak or miss areas of the windshield. Refer to Windshield Wiper Blade Replacement in Wipers/Washer Systems.

#### Weatherstrip Lubrication

Use a clean cloth in order to apply silicone grease to the weatherstrips. Silicone grease will make the weatherstrips last longer, seal better, and not stick or squeak.

#### Body Lubrication Service

Notice: Recommended Fluids and Lubricants tells you what to use. More frequent lubrication may be required when exposed to a corrosive environment.

Lubricate all of the following exposed surfaces:

• | The door checks

• | The door lock bolts

• | The lock strike plates

• | The door hinge bushings

• | The dovetail bumper wedges

Use a dripless oil where oil holes are provided.

Also lubricate the following components:

• | The seat adjusters

• | The seat track

• | The door weatherstrip

• | The rubber hood bumpers

#### Parking Brake Inspection

Use the following procedure in order to determine the parking brake holding ability:

1. Park the vehicle on a fairly steep hill.
2. Hold the vehicle with the parking brake only.

#### Starter Switch Inspection

Caution: When you are doing this check, the vehicle could move suddenly. If it does, you or others could be injured. Follow the steps below.

Follow this procedure for the starter switch inspection:

1. Ensure that there is enough room around the vehicle.
2. Firmly apply the parking brake (refer to Parking Brake in your GM Owner's Manual if necessary) and the regular brakes.

Notice: Do not use the accelerator pedal, and be ready to turn off the engine immediately if it starts.

3. On automatic vehicles, attempt to start the engine in each gear. The starter should function only in NEUTRAL (N) or PARK (P). If the starter functions in any other position, service the vehicle.

On manual transmission vehicles, place the shift lever in NEUTRAL (N). Push the clutch down halfway and attempt to start the engine. The starter should function only when the clutch is pushed down all the way to the floor. If the starter functions when the clutch is NOT pushed all the way down, service the vehicle.

#### Automatic Transmission Shift Indicator Inspection

Verify that the indicator points to the gear chosen.

#### Steering Inspection

Be alert for any of the following conditions:

• | Changes in steering action

• | Abnormal front tire wear

• | Changes in steering wheel position

Inspect or service the vehicle when the following conditions occur:

• | The steering wheel is harder to turn.

• | The steering wheel has too much free play.

• | Strange sounds can be heard during turning or parking.

#### Brake System Inspection

Be alert for any of the following conditions:

• | Illumination of the low air warning lamp

• | The tone alarm

• | Changes in braking action

- | Repeated pulling to one side

- | Unusual sounds during braking

- | Increased brake pedal travel

Ensure that the air brake system reservoirs are drained daily with full system air pressure. Inspect the system for leaks.

Any of these conditions may indicate the need for brake system inspection or service.

#### Engine Cooling System Inspection

Important: The radiator should be kept clean for proper system performance. Cleaning is recommended at least once a year.

To help ensure proper cooling system pressure performance, a pressure test of the cooling system and pressure cap is recommended at least once a year. If there is a loss of coolant, refer to Loss of Coolant in Engine Cooling.

Inspect the following components. Replace worn or damaged components as needed:

• | The hoses

• | The pipes

• | The fittings

• | The clamps

Clean the outside of the radiator and air conditioning condenser.

#### Exhaust System Inspection

Be alert for any changes in the sound of the exhaust system or any smell of fumes. These conditions indicate that the system may be leaking. Inspect or repair the exhaust system immediately, if needed.

#### Windshield Wipers and Washers Inspection

Inspect the operation and the conditions of the wiper blades.

Inspect the flow of the washer spray.

#### Defroster Inspection

Move the control to the defrost symbol. Move the fan to HI or the high symbol. Inspect the airflow from the ducts at the inside base of the windshield.

#### Mirrors and Sun Visors Inspection

Verify that the friction joints hold the mirrors and the sun visor in place.

#### Seat Adjuster Inspection

When adjusting a manual seat, ensure that the seat adjuster latches by attempting to move the seat after latching.

#### Lamps Inspection

Inspect the following lamps on the inside:

• | The panel lighting

• | The warning lights

• | The indicator lights

• | The interior lamps

Inspect the following lamps on the outside:

• | The license plate lamps

• | The sidemarker lamps

• | The reflectors or lights on the outside mirrors

• | The headlamps

• | The parking lamps

• | The identification and clearance lamps

• | The tail lamps

• | The brake lamps

• | The turn signals

• | The backup lamps

• | The hazard warning flashers

Inspect the headlamp aim if the beams seem to be inappropriately aimed.

#### Glass, Mirrors, Lamps and/or Reflectors Condition Inspection

Inspect all glass, mirrors, lamps or reflectors for the following conditions:

• | Broken

• | Scratched

• | Dirty

• | Damaged

Any of the above conditions may reduce the view or visibility or cause injury. Replace, clean, or repair promptly if necessary.

#### Door Latches Inspection

Verify that the doors perform the following functions:

• | Close

• | Latch

• | Lock tightly

Inspect for broken, damaged or missing parts that might prevent tight latching.

#### Hood Latches Inspection

Verify that the hood closes firmly.

Inspect for broken, damaged or missing parts that might prevent tight latching.

Ensure that the secondary latch, if equipped, prevents the hood from opening all the way when the primary latch is released.

#### Fluid Leaks Inspection

Inspect for fluid leaks of the following substances by looking at the surface beneath the vehicle after it has been parked for a while:

• | Fuel

• | Coolant

• | Oil

#### Underbody Inspection

Corrosive materials used for ice and snow removal and dust control may collect on the underbody. If these materials are not removed, accelerated corrosion (rust) may occur on the following underbody parts:

• | The fuel lines

• | The frame

• | The floor pan

• | The exhaust system

At least every spring, flush these materials from the underbody using plain water. Thoroughly clean any areas where mud and other debris may collect. Loosen the sediment packed in the closed areas of the frame before flushing.

#### Engine Cover Inspection

Verify that the cab's engine cover and seal, if equipped, are not torn or damaged.

Verify that the cover is bolted down firmly to the floor.

### At Least Once a Year

#### Key Lock Cylinders Service

Lubricate the key lock cylinders using the correct lubricant.

#### Underbody Flushing Service

At least every spring, use plain water to flush any corrosive materials from the underbody.

Take care to clean thoroughly any areas where mud and other debris can collect.

#### Tractor Protection (Breakaway) Valve Inspection

On air brake models, perform the following procedures on the tractor protection (breakaway) valve:

1. Remove the tractor protection (breakaway) valve.
2. Disassemble the tractor protection (breakaway) valve.
3. Clean the tractor protection (breakaway) valve.
4. Inspect the tractor protection (breakaway) valve.