NAPA Gold 1138 vs Baldwin B34: Oil Filter Compatibility
Compare NAPA Gold 1138 and Baldwin B34 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.
NAPA Gold 1138 and Baldwin B34 specifications
How matching is scored| Specification | NAPA Gold 1138 | Baldwin B34 |
|---|---|---|
| Thread size | 3/4-16 | 3/4-16 |
| Gasket OD | 70.1 mm | 71.4 mm |
| Gasket ID | 62.5 mm | 62.7 mm |
| Can OD | 93.04 mm | 93.7 mm |
| Height | 96.82 mm | 98.4 mm |
| Internal bypass valve | Yes | Yes |
| Bypass PSID | 15 - 22 | 8 |
| Anti-drainback valve | No | Yes |
What matters in this specific comparison
Thread size matches: both are 3/4-16.
Gasket OD differs by 1.3 mm (NAPA Gold 1138: 70.1 mm, Baldwin B34: 71.4 mm).
Gasket ID differs by 0.2 mm (NAPA Gold 1138: 62.5 mm, Baldwin B34: 62.7 mm).
Baldwin B34 is 1.6 mm taller (NAPA Gold 1138: 96.82 mm, Baldwin B34: 98.4 mm) -- check clearance before substituting.
Can OD differs by 0.7 mm (NAPA Gold 1138: 93.04 mm, Baldwin B34: 93.7 mm).
Both open their bypass valve in a comparable range: NAPA Gold 1138 at 15-22 psi, Baldwin B34 at 8-8 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.