What This Cooler Does
The oil cooler core sits in the housing on the side of the block and passes engine oil through stacked aluminum plates with coolant running between them. It is the only thing keeping oil temperature in range under load. On a Class-8 truck pulling grades at gross weight, that core is working every mile the engine is turning.
Construction is aluminum plate stack, which is why it is sensitive to thermal shock and to debris carried in dirty coolant. It is not a serviceable assembly. When the core leaks internally, you replace the core, clean the housing bore, and fit new seals and gaskets from a kit sourced separately.
This is an aftermarket direct replacement core for 2892304. It drops into the same housing with no core return required. It is not an OEM part and PartStop is not affiliated with or authorized by Cummins — the numbers here exist so you can identify the part you have.
Why These Numbers Cross
2892304, 4965870, 4059460, 4059252 and 3680595 all describe the same plate-stack cooler core geometry used across the ISX15, X15 and QSX15 family. Cummins revised the number over the production run as the core was superseded, kitted differently, or released under a service package rather than a bare core. The physical part that fits the housing did not change in a way that affects interchange.
That is the normal pattern on this engine family. A number stamped on a core pulled in 2012 will not match the number on the box a dealer hands you today, but both slide into the same bore and seal on the same lands. Older numbers like 3680595 and 4059252 are the ones you tend to find on high-mile cores and in old shop records.
Cross-reference is a starting point, not a fitment guarantee. Verify against your engine serial number, or read the number cast or tagged on the core you just pulled. If the old core is destroyed and unreadable, go by ESN before you order.
Diagnosing A Failed Core
The classic symptom is oil in the coolant surge tank — a brown film or a slick on top. Oil pressure is higher than coolant pressure at most operating points, so oil usually pushes into the coolant first. Coolant in the oil shows up later, or after shutdown, and turns the dipstick milky. Either way, pressure-test before you condemn anything.
Cracked or eroded plates are the usual failure. Contributing causes are coolant that was never maintained, cavitation from a low SCA or nitrite level, and thermal cycling on a truck that idles cold then goes straight to full load. Check the coolant condition and the filter setup while you have it apart, or the new core sees the same conditions.
Before ordering, confirm the engine serial number, pull the housing cover and read what is stamped on the old core, and plan on new seals and a coolant flush. If the failure dumped oil into the cooling system, the whole system needs cleaning — a new core in contaminated coolant is money spent twice.
2892304 Cross-Reference & Interchange Numbers
These manufacturer and aftermarket numbers commonly cross-reference to 2892304. 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 | 4965870, 4059460, 4059252, 3680595 |
Frequently asked questions
Will this fit my ISX15 if my old core says 4059460?
4059460 is one of the Cummins numbers that crosses to this core, so it is the right starting point. Confirm by matching the number on the part you pulled and by checking your engine serial number. Cross-reference identifies the part; final fitment is confirmed off the old core or the ESN.
Does the oil cooler come with gaskets and seals?
This listing is the cooler core itself, aluminum plate type, as a direct replacement. Seals and gaskets are ordered separately. Never reuse the old seals — they take a set in the bore and will weep as soon as the engine heats up.
Is oil in the coolant always the oil cooler?
Not always. A failed head gasket, a cracked head, or a leaking air compressor can put oil into coolant on these engines. Pressure-test the cooler core off the engine or isolate it before you commit. Replacing the cooler when the head is the problem just moves the failure back a week.
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
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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.