The **Lycoming Oil Sump Gasket (P/N 6-3-9)** is a critical sealing component engineered to create a leak-proof interface between the engine's oil sump and the crankcase assembly. This part is integral to the lubrication system of Lycoming O-320, IO-320, and LIO-320 series aircraft engines, preventing oil loss and maintaining the necessary internal pressure for proper engine operation. Its precise design ensures a secure seal against the fluctuating temperatures and pressures experienced during flight, safeguarding the engine's vital oil supply.
Overview
The Lycoming Oil Sump Gasket, identified by part number 6-3-9, serves as the primary static seal between the oil sump and the lower crankcase halves of various Lycoming four-cylinder engines. Situated within the engine's lubrication system, this gasket is essential for containing lubricating oil within the sump, where it is collected before being recirculated. A properly sealed oil sump is fundamental to preventing external oil leaks, maintaining system integrity, and ensuring that the engine receives consistent lubrication throughout its operational envelope.
Specifications
- Part Number: 6-3-9
- Stock: Out of Stock - On Backorder
- Manufacturer Part #: 6-3-9
- Part#: 6-3-9
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Returns & refund summary
- 30-day return window — with prior return authorization, unopened in original packaging.
- Restocking fee: 20% on unopened items, 30% on open-box items.
- Refund processing fee: 5.51% applies to all refunds (returns, cancellations, core-fee refunds) regardless of reason.
- Return shipping: paid by buyer.
- Non-returnable categories: installed/used parts, special-order or rebuilt items, programmed items (incl. ELTs), batteries, AOG-priority orders, international orders.
Full terms: Return Policy.
Authenticity & authorization
All parts sold by American Aviation Parts are genuine factory products sourced through authorized distribution channels. Our authorization status varies by brand — for some brands we are a direct authorized dealer; for others we are an independent reseller through authorized distribution. Either way, the part you receive is the same factory product, with standard documentation available on request.
See our full Manufacturer Authorizations page for the current per-brand status.
Need traceability paperwork?
If your installation requires FAA Form 8130-3, manufacturer Certificate of Conformance, or other traceability documentation, please call 1-877-722-8727 or email [email protected] before placing the order so we can confirm what is available for this part.
Shipping
Standard ground, expedited, and AOG shipping options are available at checkout. Full shipping-cost tiers and timelines are published on our Delivery Information page.
