Changing the Engine Oil & Filter on an AC Aceca-Bristol
The Bristol engine is a durable, well-engineered unit that will cover well over 100,000 miles — but it earns that reputation on clean oil. Change the oil and filter regularly (annually, or every few thousand miles).
Specs — confirm against your car
- Oil: a classic 20W/50 — the Bristol owners' community favour Castrol Classic XL 20/50, or an equivalent classic-car 20W/50.
- Capacity: confirm the exact sump capacity against your Bristol/AC handbook, and set the level by the dipstick. Many Bristol-engined cars also run an oil cooler, which holds extra oil — allow for it at a full change.
- Filter: originally a Vokes paper-element filter; almost all engines now have an adapter for a modern spin-on filter. Check which you have before buying parts.
Procedure
Warm the engine so the oil drains cleanly, then stop it. Chock the wheels, raise the front and set on axle stands.
Drain the sump: remove the drain plug into a pan, let it drain fully, clean the plug and renew its washer.
Renew the filter. Vokes element type: undo the filter housing (oil inside — pan ready), remove the old paper element, clean the bowl, fit the new element and reassemble with a sound seal. Spin-on (converted) type: unscrew the old filter, smear clean oil on the new seal, and spin on hand-tight plus about three-quarters of a turn.
Refit the sump plug with a sound washer, firm but not overtightened.
Refill with 20W/50 through the filler, then set the level by the dipstick. Don't overfill.
Start up — oil pressure should show promptly; if not, STOP and investigate. Check the filter and sump plug for leaks. If an oil cooler is fitted, it and its lines fill on first run, so re-check and top up the level afterwards.
Dispose of the old oil and filter at a recycling centre; log the date and mileage.
This guide is not a substitute for the official Bristol/AC Workshop Manual.
About the author
An independent classic-car enthusiast in North Yorkshire with decades of hands-on experience on British classics — including the AC Aceca — writing the single-model reference he always wished existed. Read the full bio.