Description
Single-injector external O-ring kit replacing Caterpillar 2481394 (supersedes CAT 189-5390) on 3406E, C15, C16, and C18 heavy-duty diesel engines. Manufactured by PAI Industries as 321285, the kit refreshes the body O-rings and crush seal that ride between the EUI/MEUI injector and the cylinder head — the seals that fail first when injector cups weep fuel into oil or coolant. Buy one kit per injector being serviced (six kits for a full engine set on six-cylinder 3406E / C15 / C16).
Specifications
| Manufacturer | PAI Industries (Caterpillar replacement) |
|---|---|
| Part Number | PAI 321285 |
| Part Type | External Fuel Injector O-Ring Kit (single injector) |
| Replaces | Caterpillar 2481394, supersedes 189-5390 |
| Engine Compatibility | Caterpillar 3406E, C15, C16, C18 |
| Quantity | One kit per injector serviced |
Cross References
This kit replaces or is equivalent to the following part numbers:
- Caterpillar: 2481394, 248-1394, 1895390, 189-5390
- PAI Industries: 321285
- Newstar: S-36706, S36706, CAT-2481394
- Fleetsworld: CAT-2481394-WA
Applications
This O-ring kit fits the following engines:
- Caterpillar 3406E 14.6L (1993–2003)
- Caterpillar C15 15.2L — including C15 ACERT (1999–2010)
- Caterpillar C16 15.8L (2001–2007)
- Caterpillar C18 18.1L industrial / on-highway
Representative trucks and equipment using these engines:
- Kenworth T600, T660, T800, W900 with 3406E / C15
- Peterbilt 379, 378, 387 with 3406E / C15
- Freightliner Classic, Century, Columbia with 3406E / C15
- Western Star 4900, 5900 with 3406E / C15 / C16
- Caterpillar 770 / 773 / 775 off-highway haul trucks (C18)
Use one kit per injector. Replace all external seals as a set when an injector is removed — reusing a single seal is the most common cause of post-service leaks. Verify your engine arrangement and serial number before ordering.
