FRAM PH4546 vs WIX 51381: Oil Filter Compatibility
Compare FRAM PH4546 and WIX 51381 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 M20x1.5 thread.
Quick verdict
Closest known dimensional difference: height -63 mm. Verify application-specific requirements before substituting.
- 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.
FRAM PH4546 and WIX 51381 specifications
How matching is scored| Specification | FRAM PH4546 | WIX 51381 |
|---|---|---|
| Thread size | M20x1.5 | M20x1.5 |
| Gasket OD | 72 mm | 71.98 mm |
| Gasket ID | 62 mm | 62.53 mm |
| Can OD | 93 mm | 92.99 mm |
| Height | 143 mm | 80 mm |
| Internal bypass valve | Yes | Yes |
| Bypass PSID | 12 | 12 - 15 |
| Anti-drainback valve | Yes | Yes |
What matters in this specific comparison
Thread size matches: both are M20x1.5.
Gasket OD is identical at 72 mm.
Gasket ID differs by 0.5 mm (FRAM PH4546: 62 mm, WIX 51381: 62.53 mm).
FRAM PH4546 is 63 mm taller (FRAM PH4546: 143 mm, WIX 51381: 80 mm) -- check clearance before substituting.
Can OD is identical at 93 mm.
Both open their bypass valve in a comparable range: FRAM PH4546 at 12-12 psi, WIX 51381 at 12-15 psi.
Open related filters
Before substituting, verify thread fit, gasket sealing dimensions, height clearance, bypass behavior, and anti-drainback requirements for your specific application.