Overview – PLUG, THREADED-KC 3420881
The Cummins PLUG, THREADED-KC 3420881 is specified for Cummins engine castings and accessory housings with threaded sealing ports and is supplied to the original dimensional and material standard.
Parts Characteristics
A machined threaded sealing plug with a hex drive, used to close drilled ports in the engine block, head and accessory housings – oil galleries, coolant passages and machining access points. It seals a casting, and a leaking one announces itself as a mystery oil film or a coolant weep that is hard to trace.
Applicable Models & Applications
Used across Cummins engine families wherever the casting carries a threaded port of this size and thread form. Confirm thread size and seat type against your parts book or the old plug before ordering – straight and tapered thread plugs look almost identical on the bench.
Maintenance & Replacement
Trace mystery leaks methodically: clean the area thoroughly, run the engine to temperature and watch the port with a bright light. Many weeping casting plugs are misdiagnosed as rear main or head gasket leaks, and the repair is minutes, not days.
Remove an old plug with the correct-size hex driver – rounded plug heads are the most common reason a five-minute job becomes a drilling job. If the plug is seized, soak it, work it back and forth gently, and never apply full leverage on the first turn.
Fit new plugs with the sealing method the engine manual specifies: sealant on the threads for straight-thread ports, or a fresh crush washer for washer-seated types. Torque to specification and no more – an over-tightened plug can split a casting boss, converting a consumable into a machining repair.
When an engine is opened for overhaul, replace every accessible casting plug as routine. The parts cost is trivial against engine hours, and new plugs with fresh seals are the cheapest leak insurance an overhaul can buy.
Price Reference (USD)
For planning purposes, allocate USD 5 to USD 20 per PLUG, THREADED-KC 3420881, excluding local import duties.
Value & Service
We stock brand-new machined plugs with correct thread form and seat type, checked against the engine family you quote, in single units or overhaul quantities.
Avoid counterfeit risk – Racer Machinery sources the Cummins PLUG, THREADED-KC 3420881 through verified channels and documents each shipment.
