What The 3104230 Seals
The 3104230 is the EGR valve gasket on Cummins ISX and ISX15 engines. It seals the joint at the EGR valve outlet, where recirculated exhaust leaves the valve and heads toward the intake side. It sees full exhaust temperature and pressure pulses, plus constant thermal cycling every time the truck heats and cools.
Because it lives on the exhaust side of the EGR circuit, this gasket does not just leak air. It leaks hot, soot-loaded exhaust gas into the engine compartment. That is why the failure is usually found by eye before it is found by a code — black soot streaking away from the valve flange is the tell.
The gasket relies on correct compression set to hold a seal under that heat. Once it has taken a set, been overheated, or been disturbed during an EGR valve or cooler job, it does not seal the same way again. It is a one-time-use item on reassembly.
How It Fails In Service
The common symptoms are a soot line at the valve flange, a ticking or whistling exhaust leak that changes with load, and a general loss of pull. A leak at this joint bleeds off recirculated flow, so the EGR system can no longer hit its commanded rate, and the ECM will eventually flag EGR flow or differential pressure faults.
Fuel economy drops because the engine is compensating. Drivers report the truck feels flat, and the leak gets worse as the flange face gets etched by escaping gas. Left long enough, hot gas will start attacking nearby harness routing and clamps.
Before you order, inspect both flange faces. If the sealing surfaces are pitted, warped, or carbon-welded, a new gasket alone will not fix it. Clean the faces down to bare metal, check them with a straightedge, and check the fastener condition. Retorque to the value in the Cummins service literature for your engine — do not guess.
Why These Numbers Cross
Two numbers show up on this gasket: 3104230 and FP-3104230. They describe the same physical part — same flange outline, same bolt hole spacing, same port opening, same material class rated for diesel exhaust gas and thermal cycling.
The FP Diesel number is simply that supplier's cataloging of the same sealing component; the prefix is a house identifier, not a different design. Aftermarket gasket manufacturers routinely index to the base engine builder number so parts counters can look the part up either way. It is listed here for identification only. PartStop is not affiliated with, endorsed by, or authorised by Cummins or FP Diesel.
Treat the cross-reference as a starting point, not a fitment promise. The ISX and ISX15 family ran through multiple emissions configurations, and EGR hardware changed. Confirm by VIN, or read the number stamped or tagged on the gasket and valve you pull off, before you commit.
3104230 Cross-Reference & Interchange Numbers
These manufacturer and aftermarket numbers commonly cross-reference to 3104230. 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-3104230 |
Frequently asked questions
Can I reuse the old EGR valve gasket if it looks OK?
No. This gasket seals by taking a compression set on first torque-down. Once it has been crushed and heat-cycled, it will not seal to the same thickness again. Any time the EGR valve comes off the engine, replace the gasket.
Is FP-3104230 the same part as 3104230?
They index to the same EGR valve gasket — same flange footprint, port opening, and bolt pattern. The FP prefix is that supplier's catalog identifier. Use the cross-reference to narrow your search, then verify against the number on the part you removed or against your VIN build sheet.
Will a leak at this gasket set a check engine light?
Often, yes. A leak bleeds off recirculated exhaust flow, so the EGR system cannot meet its commanded rate and the ECM can log EGR flow or delta pressure faults. But you may see the soot trail at the flange before any lamp comes on. Inspect the joint visually during any EGR-related diagnosis.
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