Oil pump tab washer. Porsche 911 / 914  ❭  99903900100

Oil pump tab washer.
Oil pump tab washer used to secure and lock the oil pump fastener in place on classic Porsche engines. It’s a simple but important locking washer designed to prevent the oil pump hardware from loosening due to engine vibration and heat cycles.

Fits:
Porsche 911 1965 - 1986
Porsche 911 Turbo 1975 - 1977
Porsche 914 1970 - 1976

Diagram ref no 4

It acts as a mechanical locking device for oil pump hardware, reducing the risk of fasteners backing out over time. By keeping the oil pump assembly secure, it supports consistent oil pressure and dependable engine lubrication.

Tab washers are designed to be bent into position - and once bent, they can fatigue or lose holding strength if reused. A weakened or reused tab washer can allow oil pump hardware to loosen, which may contribute to oil pressure issues and accelerated engine wear. Replacing it during service is cheap insurance for engine reliability.

When to replace:
•  During oil pump removal/refit or engine rebuild work
•  If the existing washer tab has been previously bent/straightened
•  Visible cracking, distortion, or fatigue around the tab
•  Any time oil pump hardware is loosened as part of maintenance

Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.

99903900100

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