What This Gasket Does
The oil cooler on an ISX sits in the engine oil circuit between the pump and the filter head, so everything the gasket seals is full-pressure, full-temperature oil. The 3069678 gasket seals the cooler to its housing and keeps oil where it belongs instead of running down the block and onto the frame rail.
When it fails you usually get a slow seep first. Oil creeps out along the cooler seam, collects road grime, and looks like a leak from three different places at once. Left alone it turns into steady loss between services, and on a hard-worked truck that means low oil level warnings and heat you did not plan for.
Heat cycling is what kills these gaskets. The joint goes from cold soak to full operating temperature every shift, and the material takes a set over time. Once it stops springing back against the sealing face, torque on the fasteners drops and the seam starts to weep. Replace it any time the cooler comes off, not just when it is leaking.
Why These Numbers Cross
3069678 is the base number most catalogs index this gasket under. FP Diesel lists the same gasket as FP-3069678, which is simply the base number carried forward with the supplier prefix on the front. That prefix pattern is common in the diesel gasket trade and it is why the two numbers land on the same shelf.
Because the numbers share a root, they describe the same physical part: same outline, same port locations, same bolt hole pattern, same sealing face. A gasket either matches the cooler footprint or it does not, so form and fit are the only things that matter for identification here.
These numbers are listed for identification only. PartStop is not affiliated with, endorsed by, or authorised by Cummins, FP Diesel, Kenworth, or Peterbilt. Use the numbers to locate the right part, then confirm it against the number on the old gasket or by VIN before you order.
Check Before You Order
Pull the old gasket and look for a number stamped or printed on it. That is the most reliable confirmation you will get. If the old one came apart during removal, get the number off the cooler housing or run the VIN through a parts lookup. A cross-reference is a starting point, not a fitment promise.
While the cooler is off, inspect the sealing faces on both the cooler and the housing. Scrape off every bit of old gasket material, then check for scoring, pitting, or a warped edge from over-torqued fasteners. A new gasket will not seal against a damaged face. Also inspect the cooler core itself for cracks and coolant-side corrosion before you button it up.
3069678 Cross-Reference & Interchange Numbers
These manufacturer and aftermarket numbers commonly cross-reference to 3069678. 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 |
|---|---|
| FP Diesel | FP-3069678 |
Frequently asked questions
Does 3069678 fit my ISX without checking anything?
Treat the cross-reference as a starting point only. Confirm fit by reading the number off the old gasket or by running your VIN before you order. Cooler assemblies vary across the ISX line, and the gasket has to match the exact cooler footprint on your engine.
Is FP-3069678 the same gasket as 3069678?
They index to the same part. FP-3069678 is the same base number carried under a supplier prefix, which is standard practice in diesel gasket catalogs. Both describe a gasket with the same outline, port layout, and bolt pattern. Verify against your old part before ordering.
Should I replace the gasket every time I pull the oil cooler?
Yes. These gaskets take a compression set once they have been through heat cycles, and a reused one rarely seals reliably. The gasket is cheap relative to the labour of pulling the cooler twice. Replace it as a matter of course whenever the joint is opened.
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.