1991 Ford F-Super Duty Oil Type & Capacity
The 1991 Ford F-Super Duty oil type depends on the engine: the 7.3 M, Automatic takes 10W-30 (10.0 quarts with filter); the 7.3 M, Standard takes 10W-30 (10.0 quarts with filter); the 7.5 G, Automatic takes 5W-30 (6.0 quarts with filter); the 7.5 G, Standard takes 5W-30 (6.0 quarts with filter), per the factory service manual.
Factory-spec answer
It depends on the engine:
- 7.3 M, Automatic: 10W-30, 10.0 quarts with filter
- 7.3 M, Standard: 10W-30, 10.0 quarts with filter
- 7.5 G, Automatic: 5W-30, 6.0 quarts with filter
- 7.5 G, Standard: 5W-30, 6.0 quarts with filter
Oil capacity by engine
| Engine | Oil Type (viscosity) | Capacity w/ Filter | Capacity w/o Filter | Notes |
|---|---|---|---|---|
| 7.3 M, Automatic — 7.3L Eng | SAE 10W-30/40 (0Deg.F to 100Deg.F), 20W-40/50 (20Deg.F to Above 100Deg.F). SAE 30 Single Weight Super Duty, 10W-40 Super Premium, 20W-40 Premium | 10.00 QTS. | 9.00 QTS. | — |
| 7.3 M, Standard — 7.3L Eng | SAE 10W-30/40 (0Deg.F to 100Deg.F), 20W-40/50 (20Deg.F to Above 100Deg.F). SAE 30 Single Weight Super Duty, 10W-40 Super Premium, 20W-40 Premium | 10.00 QTS. | 9.00 QTS. | — |
| 7.5 G, Automatic — 7.5L Eng | SAE 5W-30 Super Premium Motor Oil | 6.00 QTS. | 5.00 QTS. | — |
| 7.5 G, Standard — 7.5L Eng | SAE 5W-30 Super Premium Motor Oil | 6.00 QTS. | 5.00 QTS. | — |
Buy the right oil
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More specs & repair guides for your F-Super Duty
1991 Ford F-Super Duty factory service manualAll fluid capacities (transmission, coolant, brakes)Powered by factory manual data from our partner site AllOEMManuals.com.
Coolant capacity
31.0 quarts (29.33 L) — 50/50 mixture of FORD Premium Cooling System Fluid and water. Includes: 5 qts. in overflow bottle.
Frequently asked questions
What type of oil does a 1991 Ford F-Super Duty take?
It depends on the engine: 7.3 M, Automatic uses 10W-30; 7.3 M, Standard uses 10W-30; 7.5 G, Automatic uses 5W-30; 7.5 G, Standard uses 5W-30.
How much oil does a 1991 Ford F-Super Duty take?
Capacity depends on the engine: 7.3 M, Automatic holds 10.0 quarts with filter; 7.3 M, Standard holds 10.0 quarts with filter; 7.5 G, Automatic holds 6.0 quarts with filter; 7.5 G, Standard holds 6.0 quarts with filter.
Can I use synthetic oil in my 1991 Ford F-Super Duty?
Yes. 10W-30 is widely available as a full synthetic, and synthetic is safe (often recommended) for the 1991 Ford F-Super Duty. What matters most is matching the factory viscosity and specification, then changing the oil and filter on schedule.