What This Cooler Does
The 14-plate core sits in the oil cooler housing on the left side of the ISX15/QSX15 block and moves heat out of the engine oil into the coolant. Oil runs through one set of plate passages, coolant through the other. When the plates or the brazed joints crack, the two circuits meet and you get the classic contamination complaint.
Failure usually shows up one of two ways. Coolant in the oil turns the dipstick milky and drops oil pressure as viscosity falls off. Oil in the coolant leaves a slick film in the surge tank and coats the radiator cap. Either one means the core is pulled and inspected, not topped off and driven.
This is an aluminum core built as a direct replacement for the 14-plate design. It is a drop-in style part with no core return required, so the old cooler stays in your scrap barrel instead of going back on a pallet.
Why These Numbers Cross
4965487 and Cummins 4955831 describe the same 14-plate oil cooler core for the ISX15/QSX15 family. Cummins revised the cooler through the production run, and a number change on paper does not always mean a change in plate count, port location, or gasket face. Where the core geometry and the housing interface stayed the same, the numbers supersede or interchange.
That is why a truck built one year may have one number stamped or tagged and a truck built later carries another, while the physical part drops into the same housing. Superseded numbers are the normal way Cummins folds running changes into one service part, and the older number keeps showing up in fleet records and repair orders for years afterward.
We list 4955831 for identification only. PartStop is not affiliated with, endorsed by, or authorized by Cummins or any other engine manufacturer, and no brand name here implies a relationship.
Before You Order
Pull your engine serial number off the dataplate on the block and confirm the build against it. Cross-reference gets you to the right family of parts, but it is a starting point — fitment is confirmed by engine serial number or by the number on the cooler you just removed. Do not order off the truck model alone.
Count the plates on the old core before it goes in the scrap barrel. This is the 14-plate version. If you pull a core with a different plate count, you are looking at a different service part and the housing depth will not match.
Replace the cooler gaskets and O-rings at the same time, and clean the housing sealing face. Flush the cooling system if the old core dumped oil into it, and change the oil and filters after the repair. Debris left in the system will find its way back to the new plates.
4965487 Cross-Reference & Interchange Numbers
These manufacturer and aftermarket numbers commonly cross-reference to 4965487. 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 |
|---|---|
| Cummins | 4955831 |
Frequently asked questions
Is 4955831 the same part as 4965487?
They cross to the same 14-plate oil cooler core for the ISX15/QSX15. Cummins revised the number through production without changing the plate count or housing interface. Check the number on your old core and your engine serial number before you commit.
How do I know the oil cooler is what failed and not the head gasket?
Both can put coolant in the oil. Pressurize the cooling system with the cooler core removed and capped, and watch whether pressure holds. A cracked plate will leak on the bench. If the system holds with the cooler out, look further up at the head gasket or a liner seal.
Do I have to send the old cooler back?
No. This is a drop-in aftermarket replacement with no core return required. Keep the old unit long enough to compare plate count, port location, and gasket face against the new one, then scrap it.
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.