Donaldson P550518 vs Baldwin BT259: Oil Filter Compatibility
Compare Donaldson P550518 and Baldwin BT259 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 13/16-16 thread.
Quick verdict
Large bypass PSI mismatch: 6.5 psi · Candidate adds ADBV
- 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 P550518 and Baldwin BT259 specifications
How matching is scored| Specification | Donaldson P550518 | Baldwin BT259 |
|---|---|---|
| Thread size | 13/16-16 | 13/16-16 |
| Gasket OD | 88 mm | 91 mm |
| Gasket ID | 79 mm | 80 mm |
| Can OD | 94 mm | 93.7 mm |
| Height | 136 mm | 137.3 mm |
| Internal bypass valve | Yes | Yes |
| Bypass PSID | 12 - 15 | 20 |
| Anti-drainback valve | Yes | No |
What matters in this specific comparison
Thread size matches: both are 13/16-16.
Gasket OD differs by 3 mm (Donaldson P550518: 88 mm, Baldwin BT259: 91 mm).
Gasket ID differs by 1 mm (Donaldson P550518: 79 mm, Baldwin BT259: 80 mm).
Baldwin BT259 is 1.3 mm taller (Donaldson P550518: 136 mm, Baldwin BT259: 137.3 mm) -- check clearance before substituting.
Can OD differs by 0.3 mm (Donaldson P550518: 94 mm, Baldwin BT259: 93.7 mm).
Both open their bypass valve in a comparable range: Donaldson P550518 at 12-15 psi, Baldwin BT259 at 20-20 psi -- these ranges do not overlap.
Open related filters
Before substituting, verify thread fit, gasket sealing dimensions, height clearance, bypass behavior, and anti-drainback requirements for your specific application.