Specs, fluids & service · 1973–1991
Chevrolet K5 Blazer (1973–1991) specs, fluids and service intervals
The numbers you need in the garage, on one page: spec sheet, capacities and service intervals, wheels and tires, and the parts to order. Sourced from owners, specialists and the factory; tags marked confirm in manual haven't been checked against a factory source yet.
Spec sheet
| BUILT | 1973–1991 model years · Flint Truck Assembly, Michigan (1990–91) |
|---|---|
| BADGES | Chevrolet K5 / Full-Size / V10 Blazer · GMC Jimmy, K-Jimmy, V-Jimmy |
| CHASSIS | Ladder frame, leaf springs, live axles front & rear |
| WHEELBASE | ≈106.5 in (2.5 in longer than 1969–72) |
| BODY | Full-open (1973–75) · half-cab with removable rear top (1976–91) |
| ENGINES | 250 I6 · 305 / 307 / 350 / 400 V8 · 6.2 diesel V8 |
| TRANSMISSIONS | SM465 4-speed · TH350 · TH400 · 700R4 / 4L60 |
| TRANSFER CASE | NP205 · NP203 (to 1979) · NP208 (1981–88) · NP241 (1989–91) |
| FRONT AXLE | Dana 44 → GM 10-bolt (from 1977) |
| REAR AXLE | GM 12-bolt → GM 10-bolt |
| TRIMS | Custom Deluxe · Cheyenne · Silverado (GMC: Sierra range) |
| MILITARY | M1009 CUCV, 1983–87 · 6.2 diesel, 24/12 V |
By year
| YEARS | PLATFORM | ENGINE | OUTPUT | NOTES |
|---|---|---|---|---|
| 1973–1975 | K5 Blazer / Jimmy, full-open body | 250 I6 · 307 / 350 V8 · 400 V8 from 1975 | 350: 175 hp (1973 test) | Removable hardtop or convertible top over the whole body. NP205 or full-time NP203; Dana 44 front. |
| 1976–1980 | Half-cab | 250 I6 · 305 / 350 / 400 V8 | — | Steel roof over the front seats, removable rear top. GM 10-bolt front phased in from 1977. NP203 dropped after 1979. |
| 1981–1986 | 1981 facelift | 250 I6 (early years) · 305 / 350 V8 · 6.2 diesel from 1982 | 6.2: 130 hp / 240 lb-ft at launch | Lighter body and new front end. NP208 with shift-on-the-fly and automatic hubs. 700R4 four-speed automatic available from 1982. |
| 1983–1987 | M1009 CUCV | 6.2 diesel (non-emissions) | 155 hp / 240 lb-ft | TH400, NP208, 10-bolt axles, 3.08 gears, Eaton automatic rear locker, 24/12-volt electrics. |
| 1987–1988 | R/V series (V10 Blazer, V-Jimmy) | 305 TBI (1987) · 350 TBI · 6.2 diesel | — | Throttle-body injection on all gas engines. K5 badges dropped for 1988. |
| 1989–1991 | Final facelift | 350 TBI (L05) · 6.2 diesel | — | GMT400-style grille, NP241, 30-spline 10-bolts, serpentine belt. Rear ABS and galvanized panels from 1990. |
Fluids, capacities & service intervals
Assume nothing has been done. These trucks are 35 to 50 years old, and most have had several owners and swaps. Before you buy fluids, identify the engine, transmission, transfer case and axles, since they changed every few years. Pull the steering box and look at the frame while you're under there. Capacities vary by drivetrain, so check them in the factory manual.
| ITEM | SPEC / CAPACITY | INTERVAL | NOTES & PARTS |
|---|---|---|---|
| Engine oil & filter | Grade and capacity confirm in manual | At purchase, then per manual | Look for leaks at the rear main seal and the oil pan.Oil filter, 1987 Blazer 5.7L · RockAuto ↗Oil filter, 1987 Blazer 6.2L diesel · RockAuto ↗ |
| Air filter | Element to suit engine | At purchase; inspect at every oil change | The diesels are especially sensitive to dust ingestion, so check the airbox seals.Air filter, 1987 Blazer 5.7L · RockAuto ↗Air filter, 1987 Blazer 6.2L diesel · RockAuto ↗ |
| Fuel filter | Gas (TBI from 1987) or diesel element | At purchase | Old fuel and rusty tanks are common on trucks that have been sitting.Fuel filter, 1987 Blazer 5.7L · RockAuto ↗Fuel filter, 1987 Blazer 6.2L diesel · RockAuto ↗ |
| Spark plugs, cap, rotor & wires (gas) | Plug type and gap confirm in manual | At purchase | Most trucks have had an ignition swap at some point, so check what's fitted before ordering.Spark plugs, 1987 Blazer 5.7L · RockAuto ↗Distributor cap, 1987 Blazer 5.7L · RockAuto ↗Spark plug wires, 1987 Blazer 5.7L · RockAuto ↗ |
| Glow plugs & controller (6.2 diesel) | 12-volt plugs, including on 24-volt M1009s (resistor pack on the firewall) | Test at purchase | On an M1009, find out whether the 24-volt starting system is still original before buying parts.Diesel glow plugs, 6.2L · RockAuto ↗Glow plug controller, 6.2L · RockAuto ↗ |
| Coolant, thermostat, hoses & belts | Coolant type and capacity confirm in manual | Flush at purchase | Check for a leaking heater core while you're at it. One CK5 member lists it as a common annoyance. Trucks through 1988 use V-belts; the 5.7 switched to a single serpentine belt for 1989.Thermostat, 1987 Blazer 5.7L · RockAuto ↗Radiator hoses, 1987 Blazer 5.7L · RockAuto ↗Drive belts, 1987 Blazer 5.7L · RockAuto ↗ |
| Automatic transmission (TH350 / TH400 / 700R4 / 4L60) | ATF type and capacity confirm in manual | Pan drop, new filter and refill at purchase | Know which one you have. The 700R4 became available in 1982 and was renamed 4L60 for 1991, and M1009s use the TH400.Automatic transmission filter, 1987 Blazer · RockAuto ↗Transmission pan gasket, 1987 Blazer · RockAuto ↗ |
| Transfer case | NP208 and NP241: automatic transmission fluid (ATF) · NP205 / NP203: lubricant confirm in manual | Change at purchase | The chain-driven NP208 and NP241 take ATF, not gear oil. Check the NP241's slip-yoke seal for leaks.NP241 and NP208 seal and gasket kit · Offroad Design ↗Transfer case output shaft seal, 1987 Blazer · RockAuto ↗ |
| Front & rear differentials | Gear oil grade and capacity confirm in manual | Change at purchase | The M1009's rear has an Eaton automatic differential lock. Check the gear ratio on both axles, since mismatched swaps are common.Gear oil, 1987 Blazer · RockAuto ↗Differential cover gasket, 1987 Blazer · RockAuto ↗ |
| Front wheel bearings & locking hubs | Repack with wheel-bearing grease; set preload per manual | At purchase | 1981 and later trucks have automatic hubs, which often seize. Plenty of owners switch to manual hubs.Warn internal-style locking hubs, GM 10-bolt / Dana 44 · Offroad Design ↗ |
| Steering box, power steering fluid & frame check | Power steering fluid confirm in manual | At purchase | With the box off or the frame cleaned, look for cracks at the steering-box bolts. It's the K5's best-known weak spot.Power steering fluid, 1987 Blazer · RockAuto ↗Offroad Design bolt-in steering box frame brace, 1973–91 4WD · Offroad Design ↗ |
| Brake fluid, hoses & rotors | Brake fluid type confirm in manual | Flush at purchase | On 1988–91 trucks, check whether recall 93V119 (corroded composite front rotors) was done. Rear ABS arrived for 1990.Brake hoses, 1987 Blazer · RockAuto ↗Brake fluid, 1987 Blazer · RockAuto ↗ |
| Driveshafts & U-joints | Grease greasable joints | At purchase, then at every oil change | Lifted trucks wear driveshaft joints quickly because of the steep angles.Universal joints, 1987 Blazer · RockAuto ↗ |
| Battery & charging | Single 12 V on civilian trucks; two 12 V batteries and alternators in series on M1009s | Test at purchase | On an M1009, test both batteries and both alternators.Battery, 1987 Blazer · RockAuto ↗Alternator, 1987 Blazer · RockAuto ↗ |
Capability
| Wheelbase | ≈106.5 in (2,705 mm) 2.5 in longer than the 104-in 1969–72 truck (Wikipedia) |
|---|---|
| Payload (M1009) | 1,200 lb (544 kg) Army rating |
| Towing (M1009) | 3,000 lb (1,361 kg) Army towed-load rating; Wikipedia says six-cylinder Blazers weren't recommended for towing |
| 0–60 mph | 22.5 s Popular Science, 1973, 175 hp 350, automatic, full-time 4WD |
| Fuel economy | 9.6 mpg at 45 mph (350 V8) · 13.7 mpg at 45 mph (250 I6) Popular Science steady-speed tests, 1973 and 1974 |
| Top speed (M1009) | 55 mph (89 km/h) Governed, CUCV series |
Wheels & tires
| Bolt pattern | 6x139.7 (6x5.5") on half-ton K5s; 8-lug on one-ton axle swaps |
|---|---|
| Biggest tire · Stock | 32 in (33 in with minor trimming) |
| Biggest tire · 3 in | 33x12.50R15 |
| Biggest tire · 4 in | 33 in (35 in with trimming) |
Open the Chevrolet K5 Blazer (1973–1991) in the tire fitment tool →
Common Chevrolet K5 Blazer (1973–1991) repairs
- Repair and brace a cracked steering-box frame railDIFFICULTY 4 / 5
- Swap a worn or leaking steering boxDIFFICULTY 3 / 5
- Convert seized automatic hubs to manual locking hubsDIFFICULTY 2 / 5
- Reseal an NP208 or NP241 and fix a leaking slip yokeDIFFICULTY 4 / 5
- Rebuild the front axle ends (ball joints, U-joints, bearings)DIFFICULTY 3 / 5
- Renew leaf spring bushings and shacklesDIFFICULTY 3 / 5
- 6.2 diesel glow plugs and controllerDIFFICULTY 2 / 5
Always confirm torque figures, fluids and capacities against the factory service manual for your VIN. See the disclaimer; some parts links are affiliate links.