Donaldson P550318 vs FRAM PH43: Oil Filter Compatibility
Compare Donaldson P550318 and FRAM PH43 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 3/4-16 thread.
Quick verdict
Both use a 3/4-16 thread.
- 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.
Donaldson P550318 and FRAM PH43 specifications
How matching is scored| Specification | Donaldson P550318 | FRAM PH43 |
|---|---|---|
| Thread size | 3/4-16 | 3/4-16 |
| Gasket OD | 72 mm | 71.1 mm |
| Gasket ID | 62 mm | 62.5 mm |
| Can OD | 93 mm | 93.7 mm |
| Height | 93 mm | 111.1 mm |
| Internal bypass valve | No | Yes |
| Bypass PSID | Not applicable | 12 |
| Anti-drainback valve | No | Yes |
What matters in this specific comparison
Thread size matches: both are 3/4-16.
Gasket OD differs by 0.9 mm (Donaldson P550318: 72 mm, FRAM PH43: 71.1 mm).
Gasket ID differs by 0.5 mm (Donaldson P550318: 62 mm, FRAM PH43: 62.5 mm).
FRAM PH43 is 18.1 mm taller (Donaldson P550318: 93 mm, FRAM PH43: 111.1 mm) -- check clearance before substituting.
Can OD differs by 0.7 mm (Donaldson P550318: 93 mm, FRAM PH43: 93.7 mm).
Bypass valve presence differs: FRAM PH43 has one, Donaldson P550318 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.