FRAM PH4751 vs NAPA Gold 1581: Oil Filter Compatibility
Compare FRAM PH4751 and NAPA Gold 1581 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.
FRAM PH4751 and NAPA Gold 1581 specifications
| Specification | FRAM PH4751 | NAPA Gold 1581 |
|---|---|---|
| Thread size | 13/16"X16 | 13/16-16 |
| Gasket OD | 72 mm | 69 mm |
| Gasket ID | 62 mm | 62 mm |
| Can OD | 95 mm | 92.96 mm |
| Height | 145 mm | 131.5 mm |
| Internal bypass valve | Yes | Yes |
| Bypass PSID | 12 | 8 - 11 |
| Anti-drainback valve | Yes | 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
- FRAM PH4751 oil filter cross reference
- NAPA Gold 1581 oil filter cross reference
- FRAM PH13 oil filter cross reference
- FRAM PH20 oil filter cross reference
- FRAM PH5717 oil filter cross reference
- WIX 51581 oil filter cross reference
- Baldwin BT112 oil filter cross reference
- Fleetguard LF3488 oil filter cross reference
Before substituting, verify thread fit, gasket sealing dimensions, height clearance, bypass behavior, and anti-drainback requirements for your specific application.