1991 Mercury Cougar Oil Type & Capacity
The 1991 Mercury Cougar takes 5W-30 motor oil — 5.0 quarts with a filter change, per the factory service manual.
Factory-spec answer
5W-30 — 5.0 quarts with filter
Oil capacity by engine
| Engine | Oil Type (viscosity) | Capacity w/ Filter | Capacity w/o Filter | Notes |
|---|---|---|---|---|
| LS, 3.8 4 | SAE 5W-30 Super Premium Motor Oil | 5.00 QTS. | — | 5.0L engines have two oil drain plugs. Both must be removed to ensure proper oil drain. |
| LS, 5.0 T | SAE 5W-30 Super Premium Motor Oil | 5.00 QTS. | — | 5.0L engines have two oil drain plugs. Both must be removed to ensure proper oil drain. |
| XR7 | SAE 5W-30 Super Premium Motor Oil | 5.00 QTS. | — | 5.0L engines have two oil drain plugs. Both must be removed to ensure proper oil drain. |
Buy the right oil
Buy 5W-30 motor oil on Amazon1991 Mercury Cougar oil filter on AmazonAs an Amazon Associate we earn from qualifying purchases made through these links.
More specs & repair guides for your Cougar
1991 Mercury Cougar factory service manualAll fluid capacities (transmission, coolant, brakes)Powered by factory manual data from our partner site AllOEMManuals.com.
Coolant capacity
12.5 quarts (11.82 L) — 50/50 mixture of FORD Premium Cooling System Fluid and water
Frequently asked questions
What type of oil does a 1991 Mercury Cougar take?
The 1991 Mercury Cougar takes 5W-30 motor oil (SAE 5W-30 Super Premium Motor Oil), per the factory service manual.
How much oil does a 1991 Mercury Cougar take?
The 1991 Mercury Cougar holds 5.0 quarts with a filter change.
Can I use synthetic oil in my 1991 Mercury Cougar?
Yes. 5W-30 is widely available as a full synthetic, and synthetic is safe (often recommended) for the 1991 Mercury Cougar. What matters most is matching the factory viscosity and specification, then changing the oil and filter on schedule.