Maintenance Information: Other GMC C3500 HD

VIN CODE ID EXPLANATION

Numbers preceding the explanations in the legend below refer to the sequence of characters as listed on VIN identification label. See VIN example below.

VIN CODE ID EXPLANATION. Scheme 10

SHORT TRIP/CITY & LONG TRIP/HIGHWAY SERVICE DEFINITIONS

Note. Starting in the 1996 model year, General Motors has renamed their maintenance schedules; One is referred to as the Short-Trip/City and the other is the Long Trip/Highway schedule. These schedule requirements are similar to the familiar Severe Service and Normal schedules and can be used in place of one another.

SEVERE & NORMAL SERVICE DEFINITIONS

Note. Use the Severe Service schedule if the vehicle to be serviced is operated under ANY (one or more) of these conditions

Service is recommended at mileage intervals based on vehicle operation, emission classification, and Gross Vehicle Weight Rating (GVWR, VIN Position 4). Emission classification is identified by engine VIN code (except diesel-powered vehicles). Manufacturer's Schedules identify items to be serviced based on type of operation. Service schedules are based on the following primary operating conditions

Severe Service

1. Short Trips (4 Miles Or Less)
2. Freezing Temperatures
3. Towing Or Heavily Loaded
4. Severe Dust Conditions
5. Hot Weather, Stop-And-Go Driving
6. Extensive Idling Conditions (Taxi Or Delivery Type Service)

Normal Service

1. No Severe Service Operating Conditions

Note. Diesel-powered models require additional servicing.

COOLING SYSTEM, HOSES & CLAMPS INFORMATION (1995 MODELS)

Replace engine coolant every 36 months or 30,000 miles. Add supplemental coolant additive every 18 months or 15,000 miles (Diesel Engine Only). Check coolant strength, condition of hoses and clamps annually regardless of mileage or driving conditions. Replace hoses and clamps as necessary.

OFF-HIGHWAY VEHICLES INFORMATION

If vehicle is operated off-highway, perform the following items every 1000 miles. If vehicle is operated in mud and/or water, perform the following items daily

1. Lubricate Front Axle, Steering And Clutch Linkages, Axle And Driveshaft U-Joints, And Slip Yoke If Equipped With Fittings.
2. Lubricate Automatic Transmission External Controls.
3. Inspect Front Wheel Bearings And Lubrication.
4. Inspect Disc And Drum Brake Systems, Hoses And Lines, Lube Caliper Slide Rails.
5. Inspect Exhaust System For Leaks, Damage, Or Loose Parts And Remove Any Foreign Material Trapped By Shielding.
6. Lubricate Clutch Release Lever Pivot.

Scheme 11

Note. For more information regarding lifting and hoisting refer to the JACKING & HOISTING article in the WHEEL ALIGNMENT section.

Scheme 12

CHANGING FUEL FILTER (DIESEL)

1. Turn off engine and block drive wheels.
2. Remove fuel filler cap(s) to release any pressure or vacuum in the vehicle fuel tank(s).
3. Place a suitable container under the filter drain hose.
4. Start engine and open the drain valve. see scheme 5
5. Once fuel begins to flow from the drain hose open the air bleed valve on the top of fuel filter housing. (Scheme 13)
6. Stop the engine.
7. After all fuel has drained from filter housing, close the fuel drain valve (Fig. see scheme 5 ), and the air bleed valve. (Fig. (Scheme 13) ).
8. Dispose of drained mixture in a proper manner.
9. Loosen the element nut on the top of the fuel filter housing (Scheme 13) An oil filter type wrench may be used.
10. Remove housing cap and lift out old fuel filter element.
11. Verify filter housing and all mating surfaces are free of any water or other contamination. Some clean fuel may be left in housing, as it will be absorbed by the new filter element.
12. Install new fuel filter by aligning the widest key slot located under the element assembly cap with the widest key in the housing.
13. Push the element assembly downward until the mating surfaces make contact.
14. Install and tighten element nut by hand.
15. Bleed air from fuel/water separator as follows.
16. Open air bleed valve on top of filter housing (Fig. (Scheme 13) ).
17. Connect hose to the air bleed valve on the top of the filter housing (Fig. (Scheme 13) ).
18. Disconnect the fuel injection pump shutdown solenoid (pink wire) located on the fuel injection pump. (Scheme 14)
19. Crank the engine in 10 to 15 second intervals until clear fuel is observed at the air bleed hose (Wait 1 minute between cranking intervals to avoid overheating the starter).
20. Close the air bleed valve.
21. Connect the shutdown solenoid wire and reinstall fuel filler cap(s).
22. Start the engine and allow to idle for 5 minutes.
23. Check fuel filter assembly for leaks.
24. Dispose of drained mixture in a proper manner.

Scheme 13

Scheme 14

STARTING OUT OF FUEL DIESEL

1. Add 5 gallons of diesel fuel to fuel tank.
2. Open air bleed valve on top of filter housing (Fig. (Scheme 13) ).
3. Connect hose to the air bleed valve on the top of the filter housing (Fig. (Scheme 13) ).
4. Place a suitable container under the filter drain hose.
5. Crank the engine in 10 to 15 second intervals until clear fuel is observed at the air bleed hose (Wait 1 minute between cranking intervals to avoid overheating the starter). CAUTION: If engine starts during step #5, stop engine and close air bleed valve before attempting restart.
6. Close the air bleed valve.
7. Crank the engine in 10 to 15 second intervals until the engine starts. (Wait 1 minute between cranking intervals to avoid overheating the starter).

Scheme 15

Scheme 16

Note. For more information regarding Diesel Idle Speed Adjustments refer to the ADJUSTMENTS - 6.5L DIESEL article in the ENGINE PERFORMANCE section.

Scheme 17

Note. For more information regarding CDVR testing and service refer to the SYSTEM/COMPONENT TESTS - 6.5L DIESEL article in the ENGINE PERFORMANCE section.

Scheme 18

Scheme 19

Scheme 20

Note. For more information regarding EGR system service refer to the EGR FUNCTION TESTING article in the ENGINE PERFORMANCE section.

Scheme 21

Scheme 22

Scheme 23

Scheme 24

Scheme 25

Scheme 26

BRAKE SERVICE INFORMATION

Note. For more information regarding brake system service refer to the BRAKE SYSTEM article in the BRAKES section.

Scheme 27

Scheme 28

Scheme 29

Scheme 30

Scheme 31

SERVICE LABOR TIMES

Note. Labor times are provided, where available, within appropriate SERVICE INTERVAL table in SCHEDULED SERVICES article.

SUPPLEMENTAL RESTRAINT SYSTEM (AIR BAG)

Modification to the air bag system component or wiring can adversely affect system performance and possibly cause injury.

Note. See the AIR BAGS article in the ACCESSORIES/SAFETY EQUIPMENT Section.

Modifications or improper maintenance, including incorrect removal and installation of the Supplemental Restraint System (SRS), can adversely affect system performance. DO NOT cover, obstruct or change the steering wheel horn pad in any way, as such action could cause improper function of the system. Use only plain water when cleaning the horn pad. Solvents or cleaners could adversely affect the air bag cover and cause improper deployment of the system.

AIR CONDITIONING SERVICING

ANTI-LOCK BRAKE SYSTEM

The anti-lock brake system contains electronic equipment that can be susceptible to interference caused by improperly installed or high output radio transmitting equipment. Since this interference could cause the possible loss of the anti-lock braking capability, such equipment should be installed by qualified professionals.

On models equipped with anti-lock brake systems, ALWAYS observe the following cautions

1. DO NOT attempt to bleed hydraulic system without first referring to the appropriate ANTI-LOCK BRAKE SYSTEM article in the BRAKES Section.
2. DO NOT mix tire sizes. As long as tires remain close to the original diameter, increasing the width is acceptable. Rolling diameter must be identical for all 4 tires. Some manufacturers recommend tires of the same brand, style and type. Failure to follow this precaution may cause inaccurate wheel speed readings.
3. Use ONLY recommended brake fluids. DO NOT use silicone brake fluids in an ABS-equipped vehicle.

REPLACING BLOWN FUSES

Before replacing a blown fuse, remove ignition key, turn off all lights and accessories to avoid damaging the electrical system. Be sure to use fuse with the correct indicated amperage rating. The use of an incorrect amperage rating fuse may result in a dangerous electrical system overload.

BATTERY WARNING

BRAKE PAD WEAR INDICATOR

Indicator will cause a squealing or scraping noise, warning that brake pads need replacement.

CATALYTIC CONVERTER

To prevent catalytic converter overheating, DO NOT allow engine to idle for more than 20 minutes.

COOLANT (DEX-COOL 1995-96 MODELS)

COOLANT (PROPYLENE-GLYCOL FORMULATIONS)

To avoid possible damage to vehicle use only ethylene-glycol based coolants with a mixture ratio from 44-68% anti-freeze. DO NOT use 100% anti-freeze as it will cause the formation of cooling system deposits. This results in coolant temperatures of over 300° F (149°C) which can melt plastics. 100% anti-freeze has a freeze point of only -8° F (-22°C).

DIESEL FUEL ANTI-FUNGAL ADDITIVES

DIESEL FUEL CONTAMINATION

DIESEL FUEL REQUIREMENTS

Note: A Diesel Fuel #1 and #2 combination (Blended Fuel) may be

used, and is recommended for mild winter driving.

JUMP STARTING (TURBO DIESEL)

ELECTROSTATIC DISCHARGE SENSITIVE (ESD) PARTS

FUEL SYSTEM SERVICE

HALOGEN BULBS

RADIATOR FAN

TURBOCHARGED MODELS (TURBO-DIESEL)

WARRANTY INFORMATION