Fleetguard LF3321 vs Fleetguard LF3973: Oil Filter Compatibility
Compare Fleetguard LF3321 and Fleetguard LF3973 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 11/8-16 thread.
Quick verdict
Bypass presence unknown on one or both filters · ADBV unknown on one or both filters
- 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 LF3321 and Fleetguard LF3973 specifications
How matching is scored| Specification | Fleetguard LF3321 | Fleetguard LF3973 |
|---|---|---|
| Thread size | 1 1/8-16 UN-2B | 1 1/8-16 UN-2B |
| Gasket OD | 99.95 mm | 99.95 mm |
| Gasket ID | 91.31 mm | 90.55 mm |
| Can OD | 108 mm | 108 mm |
| Height | 261 mm | 264 mm |
| Internal bypass valve | No | Unknown |
| Bypass PSID | Not applicable | Unknown |
| Anti-drainback valve | No | Unknown |
What matters in this specific comparison
Thread size matches: both are 11/8-16.
Gasket OD is identical at 99.95 mm.
Gasket ID differs by 0.8 mm (Fleetguard LF3321: 91.31 mm, Fleetguard LF3973: 90.55 mm).
Fleetguard LF3973 is 3 mm taller (Fleetguard LF3321: 261 mm, Fleetguard LF3973: 264 mm) -- check clearance before substituting.
Can OD is identical at 108 mm.
Open related filters
Before substituting, verify thread fit, gasket sealing dimensions, height clearance, bypass behavior, and anti-drainback requirements for your specific application.