Fleetguard LF3638 vs WIX 51191: Oil Filter Compatibility
Compare Fleetguard LF3638 and WIX 51191 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.
Quick verdict
Large gasket OD variation · Large gasket ID variation
- 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.
Fleetguard LF3638 and WIX 51191 specifications
| Specification | Fleetguard LF3638 | WIX 51191 |
|---|---|---|
| Thread size | 3/4-16UNF-2B | 3/4-16 |
| Gasket OD | 71.88 mm | 71.98 mm |
| Gasket ID | 62.48 mm | 62.53 mm |
| Can OD | 94 mm | 92.96 mm |
| Height | 127 mm | 131.5 mm |
| Internal bypass valve | No | Yes |
| Bypass PSID | Unknown | 13 - 19 |
| Anti-drainback valve | No | Yes |
What matters most in this comparison?
Thread match: A direct spin-on substitute starts with the same thread size. If the threads differ, the comparison stops there.
Gasket fit: Even when thread size matches, the gasket outside diameter and inside diameter still control whether the filter seals safely against the mounting surface.
Height difference: Small height differences may be acceptable, but longer filters can create clearance problems in tighter installations.
Valve behavior: Bypass and anti-drainback differences can matter in real-world service, especially on cold start or in applications sensitive to oil drain-back.
Related filter pages
- Fleetguard LF3638 oil filter cross reference
- WIX 51191 oil filter cross reference
- NAPA Gold 1452 oil filter cross reference
- NAPA Gold 1515 oil filter cross reference
- NAPA Gold 1583 oil filter cross reference
- NAPA Gold 1775 oil filter cross reference
- NAPA Gold 1790 oil filter cross reference
- WIX 51452 oil filter cross reference
Before substituting, verify thread fit, gasket sealing dimensions, height clearance, bypass behavior, and anti-drainback requirements for your specific application.