Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSGMC1991FORWARD CONTROL 3.9 L, SM465/M20REPAIR AND DIAGNOSISENGINE PERFORMANCEENGINE CONTROLS - SPECIFICATIONSCAPACITIES
1991 GMC Forward Control 3.9 L, SM465/M20
Engine Controls - Specifications: Capacities
1991 GMC Forward Control 3.9 L, SM465/M20SECTION Capacities
BATTERY SPECIFICATIONS
| Application | Cold Crank Amp @ 0°F (-18°C) | Reserve Minutes | |
|---|---|---|---|
| 2.5L (VIN E) | 525 | 90 | |
| 2.8L (VIN R) | 525 | 90 | |
| 3.1L (VIN D) | 525 | 90 | |
| 4.3L (VIN Z) | |||
| Standard | 525 | 90 | |
| Heavy Duty | 630 | 115 | |
| 5.0L (VIN H) | |||
| Standard | 430 | 90 | |
| Heavy Duty | 525 | 90 | |
| 5.7L (VIN K) | |||
| Standard | 525 | 90 | |
| Heavy Duty | 630 | 115 | |
| 6.2L (VIN C & J) | 570 | 90 | |
| 7.4L (VIN N) | 630 | 115 | |
FLUID CAPACITIES
| Application | (1) Quantity - Qts. (L) | ||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Crankcase | |||||||||||||||||||
| 2.5L (VIN E) | (2) 3.0 (2.8) | ||||||||||||||||||
| 2.8L (VIN R) | (2) 4.0 (3.8) | ||||||||||||||||||
| 3.1L (VIN D) | (2) 4.0 (3.8) | ||||||||||||||||||
| 4.3L (VIN Z) (3) | (2) 4.0 (3.8) | ||||||||||||||||||
| 5.0L (VIN H) | (2) 4.0 (3.8) | ||||||||||||||||||
| 5.7L (VIN K) | (2) 4.0 (3.8) | ||||||||||||||||||
| 6.2L (VIN C & J) | 7.0 (6.6) | ||||||||||||||||||
| 7.4L (VIN N) | (2) 6.0 (5.7) | ||||||||||||||||||
| Cooling System (Includes Heater) (4) | |||||||||||||||||||
| 2.5L (VIN E) | 11.5 (11.0) | ||||||||||||||||||
| 2.8L (VIN R) | 10.5 (10.0) | ||||||||||||||||||
| 3.1L (VIN D) | 13.0 (12.3) | ||||||||||||||||||
| 4.3L (VIN Z) | |||||||||||||||||||
| "C" & "K" Series | 10.9 (10.3) | ||||||||||||||||||
| Other Models | 13.5 (12.8) | ||||||||||||||||||
| 5.0L (VIN H) | 17.0 (16.0) | ||||||||||||||||||
| 5.7L (VIN K) | 17.0 (16.0) | ||||||||||||||||||
| 6.2L (VIN C & J) | 25.0 (23.5) | ||||||||||||||||||
| 7.4L (VIN N) | 23.0 (22.0) | ||||||||||||||||||
| Automatic Transaxle (Dexron-II) (5) | |||||||||||||||||||
| 3.1L (VIN D) | 4.0 (3.8) | ||||||||||||||||||
| Automatic Transmission (Dexron-II) (5) | |||||||||||||||||||
| 2.5L (VIN E) | 5.0 (4.7) | ||||||||||||||||||
| 2.8L (VIN R) | 5.0 (4.7) | ||||||||||||||||||
| 4.3L (VIN Z) | 5.0 (4.7) | ||||||||||||||||||
| V8 Engines | |||||||||||||||||||
| THM 400 | 4.2 (4.0) | ||||||||||||||||||
| THM 700 | 5.0 (4.7) | ||||||||||||||||||
| Manual Transmission | |||||||||||||||||||
| 2.5L (VIN E) | (6) 2.2 (2.0) | ||||||||||||||||||
| 2.8L (VIN R) | (6) 2.2 (2.0) | ||||||||||||||||||
| 4.3L (VIN Z) | (6) 2.2 (2.0) | ||||||||||||||||||
| V8 Engines | |||||||||||||||||||
| 4-Speed (117 mm) | (7) 4.2 (4.0) | ||||||||||||||||||
| 5-Speed (85 mm) | (8) 1.8 (1.7) | ||||||||||||||||||
| 5-Speed (109 mm) | (7) 4.2 (4.0) | ||||||||||||||||||
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RENDER: 1.0x
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.