Baldwin BT261 vs WIX 51609: Oil Filter Compatibility
Compare Baldwin BT261 and WIX 51609 oil filters by compatibility, dimensions, thread size, gasket fit, bypass valve, anti-drainback valve status, and match confidence. Use this comparison as a fitment review, not as an automatic substitution guarantee. Both use a 1-12 thread.
Quick verdict
Candidate adds internal bypass; usually redundant with engine-mounted bypass
- Thread size is the first hard-fit check for any comparison of spin-on filters.
- Gasket OD and gasket ID are the most important seal-related dimensions.
- Height differences can matter for clearance even when thread and gasket fit appear close.
- Bypass and anti-drainback differences may be important, depending on the application.
Baldwin BT261 and WIX 51609 specifications
How matching is scored| Specification | Baldwin BT261 | WIX 51609 |
|---|---|---|
| Thread size | 1-12 | 1-12 |
| Gasket OD | 71.4 mm | 72.52 mm |
| Gasket ID | 62.7 mm | 63.25 mm |
| Can OD | 93.7 mm | 93.73 mm |
| Height | 181 mm | 135.6 mm |
| Internal bypass valve | No | Yes |
| Bypass PSID | Not applicable | 8 - 11 |
| Anti-drainback valve | Yes | Yes |
What matters in this specific comparison
Thread size matches: both are 1-12.
Gasket OD differs by 1.1 mm (Baldwin BT261: 71.4 mm, WIX 51609: 72.52 mm).
Gasket ID differs by 0.5 mm (Baldwin BT261: 62.7 mm, WIX 51609: 63.25 mm).
Baldwin BT261 is 45.4 mm taller (Baldwin BT261: 181 mm, WIX 51609: 135.6 mm) -- check clearance before substituting.
Can OD is identical at 93.7 mm.
Bypass valve presence differs: WIX 51609 has one, Baldwin BT261 does not.
Open related filters
Before substituting, verify thread fit, gasket sealing dimensions, height clearance, bypass behavior, and anti-drainback requirements for your specific application.