Oil drain plug O-ring. Porsche 993 1994-97  ❭  99970126940

Oil drain plug O-ring 11x2.5mm
This OE Match oil drain plug O-ring is a small sealing gasket designed for the oil drain plug on the oil thermostat housing in Porsche 911 (993) models. It provides a tight seal between the drain plug and the housing to prevent engine oil leaks during operation and after servicing.
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Fits:
Porsche 993 1994 - 1997

Diagram Ref No 6.

The oil drain plug O-ring is a rubber sealing ring installed on the oil drain plug located on the oil thermostat console or housing. Its function is to create a tight seal when the drain plug is tightened, preventing oil leakage from the engine lubrication system.

The OE Match version of part number 99970126940 is produced with the correct 11 × 2.5 mm dimensions, matching the original Porsche specification. This ensures proper compression and sealing performance when the drain plug is installed.

Because this component is removed whenever oil is drained from the thermostat housing, it is considered a service item and is commonly replaced during routine maintenance.

The O-ring seals the interface between the oil drain plug and the thermostat housing, preventing engine oil from leaking out of the lubrication system. It maintains proper oil pressure and protects the engine from oil loss.

Replacing the seal during servicing ensures the drain plug forms a secure seal and helps prevent oil seepage after maintenance.

Function
•  Leak Prevention: Seals the oil drain plug on the thermostat housing
•  Oil System Integrity: Maintains proper oil containment and pressure
•  Service Seal: Designed to be replaced during oil system maintenance
•  Engine Protection: Helps prevent oil loss and contamination

O-rings are exposed to heat, oil and repeated tightening cycles. Over time the rubber can harden, flatten or crack, which may lead to oil seepage or leaks around the drain plug. Replacing the O-ring whenever the plug is removed ensures the lubrication system remains properly sealed and helps prevent oil loss.

Consider replacing the O-ring when:
•  Performing engine oil service
•  Removing the oil thermostat housing drain plug
•  The seal appears flattened, cracked or hardened
•  Oil leakage is visible around the drain plug

Related reference numbers
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99970126940

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