What This Cooler Does
The N14 oil cooler is a bundle-style core that sits in a housing on the block, bolted under the oil filter head. Coolant runs through the housing around the core while engine oil passes through the core itself in four passes. That four-pass layout gives the oil more dwell time against the cooled surface, which is what keeps oil temperature in range when the truck is loaded and climbing.
This is an aluminum core built for Class-8 over-the-road duty cycles. It is a drop-in style replacement that goes back in the stock housing without modification, using the existing gaskets and seals from the cooler kit. Nothing gets machined, nothing gets shimmed.
Failure is usually one of two patterns. Either the core cracks or corrodes through internally and you get oil pushing into the coolant on a running engine, or coolant bleeding back into the pan when it sits. The other pattern is plugging on the oil side, which shows up as high oil temp and no visible leak anywhere.
Why These Numbers Cross
3413091, 3069677, 3412857 and 3078407 all describe the same four-pass N14 cooler core. Cummins revised the part number several times over the production life of the engine family, mostly for core construction and supersession housekeeping rather than a change in the mounting envelope or the number of passes.
That matters to you because a truck built early in the run may still have the earliest number stamped or tagged on the old core, while the parts book on a later chassis calls out a newer one. The core length, the pass count, and the way it seats in the housing carry across, which is why the numbers land in the same interchange group.
Cross-reference is where you start, not where you finish. Pull the old core and read the number off it, or verify against your engine serial number before you order. The N14 ran a long time in a lot of chassis and there is more than one cooler configuration out there in the field.
Check Before You Order
Get the engine serial number off the dataplate on the gear housing and have it in hand. On the N14, serial-break information is the fastest way to confirm which cooler configuration the engine left the factory with, and it beats guessing off a chassis year. If the engine has been swapped or rebuilt, trust the serial number, not the door sticker.
Pull the housing and inspect while you are in there. Check the housing sealing surfaces for pitting and the bore for scale buildup, and look at the coolant condition. A cooler that failed from liner-side scale or a neglected coolant service will take the new core down the same way if you do not fix the root cause.
3413091 Cross-Reference & Interchange Numbers
These manufacturer and aftermarket numbers commonly cross-reference to 3413091. 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 | 3069677, 3412857, 3078407 |
Frequently asked questions
How do I know the oil cooler is what failed and not a head gasket?
Oil in the coolant with normal compression and no combustion gases in the surge tank points at the cooler. Pressure-test the cooler core off the engine with the oil side plugged and shop air on it, submerged. A head gasket usually pushes exhaust gas into the coolant and shows up on a block test; a bad cooler generally does not.
Is 3069677 the same part as 3413091?
They fall in the same interchange group for the N14 four-pass cooler core, along with 3412857 and 3078407. Cummins revised the number over the production run. Confirm against the number on your old core or your engine serial number before ordering, because cross-reference identifies the part but does not guarantee fitment on your specific engine.
Do I need new gaskets and seals with the cooler core?
Yes. The core does not reuse the old gaskets or O-rings. Order the cooler gasket set for your engine separately and replace everything that seals between the core, the housing, and the block. Reusing compressed gaskets on a cooler housing is the fastest way to be back in there next month.
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.