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- Porsche 911 1978-1983 3.0L / SC
- Porsche 911 1984-1986 3.2L
- Porsche 993 (911) C2 1994-97
- Porsche 993 (911) C4 1994-97
- Porsche 993 (911) RS 1994-97
- Porsche 993 (911) C2S 1994-97
- Porsche 993 (911) C4S 1994-97
The OE MATCH Oil Tank Cap – Bayonet Fitting Type is a replacement engine oil tank filler cap designed for selected air-cooled Porsche 911 and Porsche 993 models equipped with the corresponding dry-sump lubrication system.
Fits:Porsche 911 1978-86*
*fit oil tank 9111070061, 91110700620, 91110707203
Porsche 911 1970-98
Manufactured to match the original equipment fitting arrangement, this cap provides a secure closure for the external engine oil tank's filler opening, helping protect the lubrication system from dirt, dust, moisture and other environmental contaminants.
Unlike conventional engines that store most of their lubricating oil in a sump beneath the crankshaft, the air-cooled Porsche 911 uses a dry-sump lubrication system with a separate oil reservoir.
This external oil tank stores the engine oil and forms an important part of the circulation system that supplies lubrication to the engine's moving components.
The oil tank filler cap allows access to the reservoir when topping up engine oil or carrying out routine servicing.
Its bayonet-style fastening mechanism is designed to engage with the corresponding oil tank filler neck, providing a secure and convenient closure.
The correct fitting and condition of the oil tank cap are important for maintaining a clean, properly enclosed oil reservoir.
Over time, an original oil tank cap may deteriorate due to repeated removal, exposure to heat, oil residue, vibration and natural ageing. The sealing surface may become damaged, while the locking tabs or bayonet mechanism may become worn or distorted.
A loose, damaged or incorrectly fitting oil tank cap may allow oil mist or residue to escape around the filler neck and permit contaminants to enter the tank.
Replacing a deteriorated cap with the OE MATCH Oil Tank Cap 91110707204/1 helps restore secure closure of the oil filler opening, maintain the cleanliness of the lubrication system and preserve the original Porsche oil tank arrangement.
Ideal for routine servicing, oil tank refurbishment, engine bay restoration and classic Porsche maintenance.
What This Product Does:
The oil tank cap provides a removable closure for the engine oil reservoir's filler opening.
Its primary functions include:
- Closes the Oil Filler Opening: Provides a secure cover for the external engine oil tank.
- Helps Prevent Contamination: Reduces the entry of dust, dirt and debris during normal vehicle operation.
- Reduces Moisture Ingress: Helps prevent rainwater, splashes and other external moisture from entering through the filler opening.
- Provides Secure Bayonet Engagement: Uses the corresponding bayonet-style locking mechanism to retain the cap on the filler neck.
- Helps Contain Oil Mist: Reduces the escape of oil mist and minor oil residue around the filler opening.
- Maintains Oil Tank Cleanliness: Helps protect the oil stored within the dry-sump lubrication reservoir.
- Supports Routine Oil Servicing: Can be removed to allow engine oil to be added through the correct filler point.
- Maintains Original Equipment Fitment: Preserves the factory-style oil tank cap arrangement.
- Protects the Filler Neck: Covers the opening when oil is not being added.
- Supports Lubrication System Maintenance: Helps maintain a clean and properly closed oil reservoir.
Symptoms Of Wear Or Failure:
The oil tank filler cap is regularly removed during maintenance and is exposed to heat, engine oil and vibration.
Over time, the locking mechanism and sealing surfaces may deteriorate.
Common symptoms of a worn or failing oil tank cap include:
- Loose-Fitting Cap: The cap may not sit securely on the oil tank filler neck.
- Difficulty Locking the Cap: The bayonet tabs may no longer engage smoothly or correctly.
- Cap Not Remaining Secure: A damaged locking arrangement may allow the cap to loosen.
- Worn Bayonet Tabs: Repeated operation or incorrect installation may wear the retaining surfaces.
- Damaged Sealing Surface: The cap may no longer make proper contact with the filler neck.
- Hardened or Deteriorated Seal: Where a sealing element is fitted, ageing may cause it to become brittle, flattened or damaged.
- Oil Residue Around the Filler Neck: Oil mist or seepage may appear around a cap that is not closing correctly.
- Oil Smell in the Engine Compartment: Oil vapours escaping around the filler opening may produce a noticeable odour.
- Visible Cracks or Deformation: Physical damage may prevent the cap from fitting or locking correctly.
- Corrosion or Deterioration: Age-related damage may affect the cap's locking or contact surfaces.
- Missing Oil Tank Cap: The original cap may have been misplaced during servicing.
- Incorrect Replacement Cap: A cap with the wrong locking arrangement may not fit the oil tank correctly.
- Contamination Around the Filler Opening: Dirt and debris may accumulate where the filler neck is not adequately covered.
Why Replacement Matters:
Replacing a worn, damaged or missing oil tank cap is important for maintaining the cleanliness and correct closure of the dry-sump lubrication system.
- Restores Secure Oil Tank Closure: Replaces a loose or damaged cap with the correct bayonet-style fitting.
- Helps Prevent Dirt Ingress: Protects the oil reservoir against external contamination.
- Reduces Moisture Exposure: Helps prevent water and moisture entering through the filler opening.
- Maintains Oil Cleanliness: Supports the condition of the oil stored within the external reservoir.
- Reduces Oil Mist Escape: Helps contain oil mist and minor seepage at the filler neck where the cap is responsible.
- Supports Reliable Cap Retention: Provides the specified locking engagement for compatible oil tanks.
- Maintains Original Equipment Appearance: Restores the factory-style filler cap arrangement.
- Protects Lubrication System Components: Helps prevent foreign material entering the oil circuit through the filler neck.
- Improves Servicing Convenience: Provides a correctly fitting cap for routine oil top-ups.
- Supports Preventative Maintenance: Addresses wear before the cap becomes insecure or is lost.
- Original Equipment-Style Fitment: Designed to correspond with the specified Porsche bayonet filler arrangement.
- Suitable for Engine Bay Restoration: Helps maintain the original appearance of classic Porsche oil tank installations.
- Cost-Effective Replacement: A relatively simple component that helps protect an important lubrication system.
The external oil tank is a critical part of the dry-sump lubrication system used in air-cooled Porsche engines.
Keeping the oil reservoir properly closed helps prevent foreign material from entering the oil supply.
Dirt, water or other contamination introduced through an open or improperly covered filler neck can affect lubricant cleanliness and may contribute to unwanted wear if it circulates through the engine.
A damaged cap may also allow oil residue to accumulate around the filler opening, making the engine compartment harder to keep clean and potentially obscuring other leaks.
Although replacing the filler cap will not cure unrelated oil leaks or lubrication problems, fitting the correct cap restores an important protective feature of the oil tank.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
91110707204
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