Onan 3008400-AM Pump Mounting Gasket
The Onan 3008400-AM Pump Mounting Gasket seals the joint it is fitted to on the pump, keeping raw water inside the wet end and out of the bearing housing and the engine bay. It also sets the running clearance across that joint, which is why a gasket of the correct thickness matters as much as the seal itself on a flexible impeller pump.
Gaskets fail by hardening, splitting at the fastener holes, and by being torn during disassembly. The usual symptoms are a salt trail or a slow drip at the joint, air drawn in on the suction side so the pump will not prime, or corrosion creeping across the flange. Always fit a fresh gasket when the joint is opened, and clean both faces back to bare metal first. This is the aftermarket equivalent of mounting gasket 3008400.
Key Features
- Die cut to the Onan flange and fastener pattern for a drop in fit
- Sets the correct standoff between the mating faces
- Seals against raw sea water and coolant side seepage
- Single use sealing part, no trimming or fitting required
- Inexpensive insurance whenever the joint is opened
Applications
- Raw water pump removal, refitting and overhaul on Onan generator sets
- Sealing the pump to engine joint after a pump change
- Correcting a weeping or salt crusted pump flange
- Stocking as a spare alongside impeller and seal service parts
Specifications
- Brand: Onan
- Manufacturer Part Number: 3008400-AM
- Part Type: Pump Mounting Gasket
- Quantity Per Pump: 1
- Condition: New
- Shipping Weight: 0.2 lb
Frequently Asked Questions
Q: Should I buy more than one?
Most owners keep a spare aboard, since a torn gasket during a service will otherwise stop the job until a new one arrives.
Q: Can I reuse the old gasket if it looks intact?
It is not worth it. The gasket has already taken its compression set, and refitting it usually produces a slow weep at the joint.
Q: Do I need sealant as well?
Normally no. These gaskets are designed to seal dry on clean faces. Sealant can squeeze into the pump and cause more trouble than it solves.
Q: How should I prepare the faces?
Scrape off all the old material, avoid gouging the metal, then wipe both faces with solvent so they are dry and oil free.
Not sure this is the right part? Send us a Picture of the Pump Plate on your pump and the CLR Marine team will confirm the correct pump mounting gasket.
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