What size are the threads on an oil filter?
There isn’t a single universal thread size for oil filters. The most common options are 3/4-16 UNF (an inch-based size) and metric sizes such as M20x1.5 or M22x1.5, with the exact size determined by the engine design and filter model. Always verify the correct size for your vehicle using the owner's manual, the filter packaging, or the engine manufacturer’s specs.
Oil filter thread size is determined by the engine block or filter housing interface. In practice, manufacturers choose a thread diameter and pitch to match the mounting point and sealing surface, so the size can vary across makes, models, and production years. Getting it wrong can lead to leaks, cross-threading, or improper oil pressure. The sections below outline the sizes you’re most likely to encounter and how to confirm the right one for your car.
Common thread sizes you’ll encounter
These are the thread families you’ll most often see on passenger vehicles. The exact size for a given car is specified by the manufacturer, so always cross-check the exact part number when shopping.
- 3/4-16 UNF: A widely used inch-based thread on many North American and Asian vehicles with spin-on filters. Major diameter is about 19 mm, with 16 threads per inch.
- M20x1.5: A frequent metric thread on European makes and some Asian brands.
- M22x1.5: A larger metric option used on certain European and diesel applications.
Beyond the thread itself, the seal type (gasket versus O-ring) and the filter base design affect compatibility. When shopping, note the filter’s part number and cross-check with the manufacturer’s catalog to ensure a proper fit.
Seal types and compatibility
Oil filters come with different seal styles. Most spin-on filters use a gasket-style external seal, while some cartridge-style or specialty filters use an O-ring or a different mounting interface. Even when the thread size matches, an incompatible seal type can cause leaks or improper sealing, so verify both thread size and seal style.
How to identify your oil filter thread size
Use a straightforward verification process to confirm the exact size for your vehicle. The steps below guide you through identifying the correct thread without relying on memory alone.
- Consult the vehicle’s owner’s manual or official service site to find the recommended filter specification for your exact year, make, model, and engine code.
- Check the packaging or the filter itself for a listed thread size or a part number that can be cross-referenced with the manufacturer’s catalog.
- Measure the existing threads if you have access to the old filter or the engine mounting area: use calipers to determine the major diameter and count threads per inch (or determine the pitch for metric threads).
- Use a cross-reference tool at an auto parts store or the filter manufacturer’s website to confirm compatibility with your engine and confirm both thread size and seal type.
- When in doubt, contact the dealer or the manufacturer’s technical support with your engine code to confirm the exact thread specification before purchasing.
Accurate identification helps prevent leaks, cross-threading, or mismatched components. Relying on the correct part number is typically the quickest and safest route.
Practical tips for shopping and replacement
- Bring the old filter or its packaging to the parts counter to verify thread size and seal type.
- If you’re working on a high-mileage vehicle or a specialized engine, consider using a manufacturer-approved cross-reference to ensure compatibility.
- Some brands offer universal adapters or filters that fit multiple thread sizes; ensure any adapter kit is appropriate for your engine’s pressure and filtration needs.
Summary
Oil filter threads are not standardized across all vehicles. The most common sizes you’ll encounter are 3/4-16 UNF and metric sizes such as M20x1.5 and M22x1.5, but the exact size depends on the engine and filter base. Always verify the correct thread size and seal type using the owner's manual, the filter packaging, or the manufacturer’s cross-reference tools. When in doubt, consult a parts professional or the vehicle dealer to ensure a proper fit and reliable sealing.
What is the thread on a standard oil filter?
The most common oil filter thread sizes are 3/4"-16 (standard) and M20 x 1.5 (metric). However, other common sizes exist, such as 13/16"-16 and 5/8"-18. It's crucial to confirm the exact size for your vehicle before purchasing a filter to avoid damage, as using the wrong size can cause leaks or a sudden loss of oil pressure.
Common thread sizes
- 3/4"-16: A widely used standard size, often found on American-made vehicles.
- M20 x 1.5: The most common metric thread size.
- 13/16"-16: Another standard size, sometimes found on different engines.
- 5/8"-18: A less common size, but still used on certain engines, particularly some European and classic British cars.
How to find your car's oil filter size
- Check the old filter: Look for a part number or thread size printed on the old filter.
- Use an open-end wrench: If you can't find a size on the old filter, try slipping a 3/4" open-end wrench over the mounting threads. If it fits, you likely have a 3/4"-16 filter. If not, you may have a metric thread.
- Consult your vehicle's manual: Your owner's manual will specify the correct oil filter size and part number for your car.
Are all oil filter threads the same?
However, not all oil filters are universal. They are engineered in different shapes, sizes, and specifications to match the needs of various engines and oil systems.
How to measure oil filter thread size?
Use a caliper or a ruler to measure the distance across the filter. This measurement will give you a good indication of the size of the wrench you need. Make sure to measure accurately to avoid any misfits.
What size is a filter thread?
To filter thread size, check the front of your lens or lens cap for a circle with a horizontal line through it, followed by a number (e.g., Ø67mm). This number is the filter diameter in millimeters and must match the size of the filter you buy to ensure a proper fit without vignetting. For multiple lenses, it's often more economical to buy one large filter and use step-up rings to adapt it to smaller lenses.
How to find and use filter thread size
This video explains how to find your camera's filter thread size: 55sPolarProYouTube · Sep 21, 2023
- Find the size on your lens: Look for a symbol that looks like a circle with a line through it (Ø) followed by a number, such as Ø58mm or Ø77mm. This marking is often on the front of the lens itself, or sometimes printed on the lens cap.
- Match the filter to the lens: The number you find is the filter diameter you need. You must purchase a filter with the exact same millimeter (mm) measurement to ensure it screws on correctly.
- Understand common sizes: Common filter sizes include 49mm, 52mm, 58mm, 62mm, 67mm, 72mm, 77mm, and 82mm, though your lens may have a different size.
- Use step-up/step-down rings:
- Step-up rings: Allow you to use a larger filter on a smaller lens. This is a useful option to save money if you have several lenses with different sizes by only buying one large filter and a few rings.
- Step-down rings: Allow you to use a smaller filter on a larger lens. However, using a step-down ring that is smaller than one or two sizes can cause the filter to block light and create dark corners (vignetting) in your photos, so they should be avoided if possible.
- Avoid "stacking" filters if possible: While some filters have threads on the front to allow another filter to be attached ("stacked"), this can lead to undesirable effects like ghosting.
