Both the 5.0L and 5.8L Windsor V8 take 6 quarts of motor oil with a fresh FL-1A filter. Use 5W-30 in 1989–1996 trucks and either 5W-30 or 10W-30 in 1978–1988 trucks — pick the heavier grade if you live somewhere hot and the engine has miles on it.
The Windsor V8 in any full-size Bronco was designed around the FL-1A filter and a 6-quart sump. Ford updated the recommended viscosity to 5W-30 across the entire model range in a later TSB, so even on a 1980 truck running 5W-30 is acceptable. In Phoenix or anywhere else that bakes the engine bay, 10W-30 holds film strength better at temperature if your engine is past 150,000 miles or runs a touch loose. Don't overfill — putting 7 quarts in because someone told you "another quart for the filter" foams the oil and pushes it out the rear main.
The drain plug is at the rear of the pan, takes a 15/16" socket on most years, and uses a soft aluminum or copper crush washer that should be replaced every other change. The oil filter screws onto a boss on the driver's side of the block. On TTB trucks (1980–1996), the filter sits behind the front axle beam — you'll catch oil on the beam and on the front driveshaft if you yank the filter without a long-spout funnel or a finger dam under it. A piece of cardboard between the filter and the axle saves cleanup.
Hand-tighten the new filter after wiping the mating surface and pre-oiling the gasket. Three-quarter turn past contact is enough; do not use a filter wrench to install. Torque the drain plug to 20–25 ft-lb on the rear sump bolt — these aluminum-washer plugs strip aggressively if you go to 40.
Run the engine for a minute, check for leaks at the filter and drain plug, then shut it down and recheck the dipstick after five minutes. Stop adding oil when the level is at the upper mark, not above it.
| Part | Vendor | Est. price |
|---|---|---|
| Motorcraft FL-1A oil filter | Motorcraft | ~$8 |
| Motor oil — 6 quarts 5W-30 conventional | Valvoline/Castrol/Mobil 1 | ~$28 |
| Motor oil — 6 quarts 10W-30 conventional (early trucks, hot climates) | Valvoline/Castrol | ~$25 |
| Drain plug gasket (crush washer) | Dorman | ~$2 |
Written and maintained by an AZ wheeler and driveway wrencher. Always cross-reference your factory service manual — modifications affect vehicle safety and warranty. Work at your own risk.