The Motorcraft FL-500S is Ford's spin-on oil filter for mid-size Ford and Mercury vehicles from the 1980s through early 2000s

The Motorcraft FL-500S is a spin-on oil filter — the kind you twist off and twist back on by hand — designed specifically for Ford and Mercury engines. It fits vehicles like the Ford Ranger, Ford Bronco II, Mercury Cougar, and some Ford Mustangs built between roughly 1983 and 2003. The "FL" stands for Ford Lubrication, and the "500S" identifies this particular size and thread pattern.

If you own one of these vehicles and need to change your oil, the filter number tells you exactly what will fit. Using the correct filter matters because the wrong one can leak, restrict oil flow, or not seal properly — any of which damages your engine over time.

Key Takeaways

  • The FL-500S is a spin-on filter made by Ford for specific mid-size Ford and Mercury models from the 1980s through early 2000s.
  • You can find the correct filter for your vehicle by checking your owner's manual or asking a parts counter to cross-reference your vehicle's year, make, and model.
  • Spin-on filters like this one screw on and off by hand, making them simpler to change than cartridge-style filters.
  • The filter should be changed every time you change your oil, following your vehicle's maintenance schedule.

How to identify whether your vehicle uses the FL-500S

The safest way to confirm your vehicle needs this filter is to check your owner's manual — it will list the correct filter part number for your specific year and engine. If you no longer have the manual, you can also take your vehicle's year, make, model, and engine size to any auto parts store and ask them to look it up in their system. They can cross-reference your vehicle against Ford's specifications and tell you whether the FL-500S is correct.

You can also look at the filter currently on your vehicle. Spin it off and read the part number printed on the side. If it says FL-500S, you know that is what your vehicle uses. Write down the number so you have it for future reference.

What the filter does inside your engine

Oil circulates through your engine constantly while the engine runs. As it moves, the oil picks up tiny particles — metal shavings from moving parts, carbon buildup from combustion, dirt that sneaks past the air filter. If those particles stay in the oil, they act like sandpaper inside your engine, wearing down bearings and cylinder walls.

The oil filter traps those particles in a pleated paper element inside the filter housing. Clean oil flows back into the engine; the dirt stays trapped in the filter. When you change your oil, you throw away the old filter with all the trapped particles and install a new one.

Spin-on filters versus cartridge filters

The FL-500S is a spin-on filter, meaning the entire filter — housing, element, and all — screws onto a threaded post on your engine. When you change it, you unscrew the whole thing and throw it away, then screw a new one on. This design is simpler than a cartridge filter, which requires you to open a housing, pull out just the element, and install a new element inside the same housing.

Spin-on filters are faster to change and leave less room for error because you are not reassembling parts. The trade-off is that you generate more waste — you throw away the metal housing each time instead of reusing it. For most home mechanics, the simplicity is worth it.

Where to find the FL-500S and what it costs

The FL-500S is an older filter, but it is still in production and widely available. You can find it at any major auto parts chain — AutoZone, O'Reilly, NAPA, Advance Auto Parts — either in stock or by special order. You can also order it online from those same retailers or from Amazon. Motorcraft filters are also sold at Ford dealerships.

Prices vary slightly by retailer, but a Motorcraft FL-500S typically costs between $6 and $12. Aftermarket equivalents from other manufacturers (Fram, Purolator, Bosch) are often a dollar or two cheaper but perform the same function. If you are unsure whether an aftermarket filter will fit, ask the parts counter to confirm the thread size and diameter match.

How often to change the FL-500S

The filter should be changed every time you change your oil. Your vehicle's owner's manual specifies the oil change interval — typically every 3,000 to 5,000 miles for older vehicles, though some specify longer intervals. You do not change the filter at a different schedule; they go together.

If you drive in severe conditions — towing, frequent short trips, dusty environments, or extreme heat — your manual may recommend shorter intervals. Check the severe-service schedule in your owner's manual if you fall into any of those categories. Changing the filter more often than recommended does no harm and may extend engine life, but changing it less often than recommended increases wear.

Steps for changing the FL-500S yourself

If you decide to change the filter yourself, the process is straightforward. Warm up the engine for a minute or two so the oil flows more easily, then turn it off and wait a few minutes. Locate the filter on your engine (your manual shows where), place a drain pan underneath, and unscrew the old filter by hand. If it is stuck, wrap a filter wrench around it for leverage.

Wipe the threaded post clean with a rag. explore a thin layer of new oil to the rubber gasket on the new filter — this helps it seal and makes removal easier next time. Screw the new filter on by hand until the gasket touches the engine, then turn it another three-quarters of a turn. Do not over-tighten; hand-tight plus three-quarters turn is correct. Start the engine and check for leaks around the filter. If you see oil dripping, turn off the engine, wait a minute, and tighten the filter a bit more.

Frequently Asked Questions

Can I use an aftermarket filter instead of the Motorcraft FL-500S?

Yes. Aftermarket filters from Fram, Purolator, and Bosch are designed to fit the same thread size and diameter. They perform the same filtering function, though some people prefer Motorcraft filters because they are made by Ford. Ask the parts counter to confirm the thread size matches before you buy.

What happens if I install the wrong filter?

The wrong filter may not seal properly, causing oil to leak around the gasket. It could also have a different thread size, making it impossible to screw on, or a different diameter, causing it to hit engine components. Always confirm the part number matches your vehicle before installation.

How tight should I screw the filter on?

Hand-tight plus three-quarters of a turn is the standard. This is tight enough to seal but not so tight that you cannot remove it next time. Over-tightening can damage the gasket or the threaded post. If you cannot remove a filter by hand at the next change, it was installed too tight.

Is the FL-500S still made, or is it obsolete?

The FL-500S is still in production. Motorcraft and aftermarket manufacturers continue to make it because many Ford and Mercury vehicles from that era are still on the road. You should have no trouble finding one at any auto parts store.