Whether you’re wrenching on a first‑gen classic or booking service for your brand-new Bronco, using the correct oil weight and Ford specification matters for longevity, warranty coverage, and performance. Below you’ll find the recommended viscosities and Ford specs for every Bronco era—starting with today’s 6th‑gen models and working back to 1966. Where years share the same requirement, they’re grouped together to keep this easy to scan. Always confirm capacity with your dipstick after refilling.

2025–2021 Bronco (6th Gen: 2.3L, 2.7L & Raptor 3.0L)

2.3L EcoBoost I‑4

• Viscosity: SAE 5W‑30

• Ford spec: WSS‑M2C961‑A1 (Motorcraft XO‑5W30‑Q1SP/Q1FS)

• Fill (incl. filter): ~6.0 qt (5.67 L)
  Track use alternative: SAE 0W‑30 meeting WSS‑M2C963‑A1.

2.7L EcoBoost V6

• Viscosity: SAE 5W‑30 (cold‑climate alternative 0W‑30 shown in the Ford chart)

• Ford spec: WSS‑M2C963‑A1 / WSS‑M2C961‑A1 equivalent oils are commonly used in kits
  Typical refill is about 6 L (~6.3 qt).

Bronco Raptor 3.0L EcoBoost

• Viscosity: SAE 5W‑50 full synthetic

• Ford spec: WSS‑M2C931‑E1 (Motorcraft XO‑5W50‑QGT)

• Fill (incl. filter): ~5.7 qt (5.4 L)

Tip: Ford explicitly warns against supplemental oil additives; they’re unnecessary and could cause damage not covered by warranty.

1996–1989 Bronco (5th & Late 4th Gen) – One Back-Spec Fits All

In the late 1990s Ford issued a service bulletin standardizing SAE 5W‑30 for virtually all gasoline engines, including the 1989–1996 Bronco line. Owner’s manuals for these years call 5W‑30 “preferred” for 5.0L/5.8L V8s. Typical capacity is ~6.0 qt with filter.

1988–1978 Bronco (Early Full-Size Era)

From the late ’70s through the ’80s, Ford originally listed heavier oils (10W‑30 in warmer temps, sometimes 5W‑30 for colder climates). If you want to follow Ford’s later guidance, 5W‑30 synthetic or blend is acceptable. For higher-mileage or looser-tolerance engines, many owners still run 10W‑30.

1977–1966 Bronco (First Gen Classics)

Factory guidance varied by ambient temperature, but SAE 10W‑30 conventional was a common choice for the inline‑six and small-block V8s. High‑zinc conventional 10W‑30 is popular today to protect flat-tappet cams in rebuilt classics. Ford’s later blanket recommendation of 5W‑30 also technically applies, but many classic owners stay with 10W‑30/10W‑40 and frequent changes.

How To Read Ford’s Specs (WSS Codes)

Beyond viscosity, Ford assigns a specification code (e.g., WSS‑M2C961‑A1) that the oil must meet. Many aftermarket synthetics do, but always verify the label. Using an oil that doesn’t meet the spec can affect warranty coverage and performance.

Quick Reference Snapshot

• 2025–2021 Bronco (2.3L / 2.7L): 5W‑30, Ford WSS‑M2C961‑A1 (track: 0W‑30 WSS‑M2C963‑A1). Raptor: 5W‑50 WSS‑M2C931‑E1.

• 1996–1989 Bronco: 5W‑30 per Ford TSB; ~6 qt with filter.

• 1988–1978 Bronco: Originally 10W‑30/5W‑30 depending on climate; 5W‑30 acceptable under Ford’s later guidance.

• 1977–1966 Bronco: 10W‑30 conventional (often high‑zinc for rebuilt V8s); Ford later back‑speced 5W‑30.

Conclusion

Picking oil for a Bronco is simpler once you know the generation and Ford spec. Modern 6th‑gen trucks use 5W‑30 (or 5W‑50 for the Raptor) that meets Ford’s WSS standards; late-model ’80s–’90s Broncos were officially moved to 5W‑30 via a Ford bulletin; and early classics generally ran 10W‑30 but can use today’s 5W‑30 if it meets spec and suits engine condition. Need the right oil and a proper install? Schedule an oil change with the Jim Burke Ford service team—we’ll make sure your Bronco leaves with the correct viscosity, spec, and fill every time.