What This Kit Covers
This is a complete water pump kit, not a bare pump. You get the cast iron pump body with a steel multi-groove impeller, plus the gaskets and O-ring needed to seal it back to the block. That matters on the 855, because a reused gasket on a gear-driven pump is a slow coolant leak waiting to happen behind the accessory drive.
The pump is gear-driven off the engine, not belt-driven. Drive gear engagement and backlash are set by the pump housing sitting flat against its mounting face. Any old gasket material left on that face throws the pump out of position and puts the gear teeth in a bind. Scrape it clean, back to bare metal, before the new gasket goes on.
Applications are Cummins 855-series and N14 engines in the 310, 330, 350, 370 and 410 hp ratings. That covers a lot of Kenworth W900 and T800, Peterbilt 379 and 378, Freightliner FLD and Classic, International 9400, Western Star, Mack, and Volvo-family trucks spec'd with the Cummins 855 or N14.
How These Numbers Cross
4919820 and PAI 181812 describe the same physical assembly: same gear-driven cast iron pump for the Cummins 855 platform, same mounting face, same impeller configuration, same seal package in the kit. The numbers differ because they come from different catalogs, not because the hardware differs. PAI publishes its own numbering for the heavy-duty aftermarket; the number on your old pump casting may be different again.
Cross-reference numbers exist so you can identify a part, nothing more. PartStop is not affiliated with, endorsed by, or authorised by any OEM, and other manufacturers' numbers appear here strictly for identification.
Treat the cross as a starting point. Confirm the engine model and read the number stamped or cast on the pump you are pulling, or verify by VIN, before you order. The 855 ran a long production life and pumps were revised over that span — the number on the part in your hand is the one that settles it.
How These Pumps Fail
The usual first sign is the weep hole. Coolant seeping from the drain under the pump means the shaft seal is done, and that seep turns into a stream once the seal opens up. A crusty green or pink trail down the block face counts as a failure even if it is dry when you look at it cold.
Bearing failure comes next. Grab the drive gear and check for shaft play — any rock or roughness when you turn it means the bearing is gone and metal is on its way through the cooling system. On a gear-driven pump a seized bearing can chew the drive gear, so do not run it out.
Third pattern is erosion. Poor coolant chemistry pits the impeller vanes and the pump stops moving volume even though nothing leaks. Symptom is overheating under load and at low road speed while the truck runs fine on the highway. Check coolant condition and the SCA level while the system is open — a fresh pump in bad coolant is a repeat job.
4919820 Cross-Reference & Interchange Numbers
These manufacturer and aftermarket numbers commonly cross-reference to 4919820. Use them to identify the part — then confirm the exact fit by VIN or the number stamped on your old unit before you order. An interchange is a starting point, not a fitment guarantee.
| Brand / Line | Cross-Reference Numbers |
|---|---|
| PAI | 181812 |
Frequently asked questions
Does the kit include the gaskets or do I order those separately?
Gaskets and the O-ring are included in the kit. You install the pump with fresh seals, which is how you avoid a comeback leak on the mounting face. Have gasket scraper and a clean rag ready — the block face has to be bare before the new gasket goes down.
Will this fit my N14 if my old pump has a different number on it?
Possibly, but do not assume it. Cross-referenced numbers are for identification and are a starting point, not a fitment promise. Read the number on the pump you removed and confirm your engine model, or verify by VIN, before ordering.
What is the pump body made of?
Cast iron, with a steel multi-groove impeller. That is the same construction used on the gear-driven 855 and N14 pumps, and it holds up in high-hour vocational and on-highway service. It is a premium quality aftermarket direct replacement, not a plastic-impeller light-duty design.
Not sure it fits? We check before you pay.
Run your VIN and we’ll match parts to your exact truck, or call the counter — a person who knows trucks verifies fitment by OEM number before the order ships. No wrong-box returns.
More cross-reference guides
Need the part, not just the reading?
Every part below is a Premium Quality aftermarket Direct Replacement with published OEM cross-reference numbers, a 6+ month warranty and same-business-day shipping from Tacoma, WA. Not sure it fits? Run your VIN — or call and a person who knows trucks will verify fitment before you pay.