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Starting at $8.95, AutoBuffy stocks 1 ignition knock sensor seals from Elring. This rubber or O-ring seal fits between the knock sensor and its mounting bore in the engine block, keeping coolant and oil from seeping past the sensor. A failed seal can allow fluid intrusion that corrupts knock sensor readings, triggering fault codes and rough engine behavior.
The main decision is matching the seal material and geometry to your engine's specific mounting bore. Some engines use a flat gasket-style seal, others use a round O-ring, and diameter tolerance matters — an ill-fitting seal will not seat correctly and will leak again quickly. Always cross-reference your engine code, not just the vehicle model, before purchasing.
| Option | Best for | What you get |
|---|---|---|
| OEM-specification rubber O-ring | Factory-correct fit on engines that use a round-profile bore | Exact material hardness and diameter matching original equipment; lowest risk of repeat leaks |
| Flat rubber gasket seal | Engines with a flat-face knock sensor mounting surface | Even compression across the seating surface; often sold as part of a knock sensor kit |
| Silicone-compound seal | High-heat applications or engines known to run higher coolant temperatures | Superior heat and chemical resistance compared to standard EPDM rubber; longer service life in demanding conditions |
| Knock sensor seal kit (seal + hardware) | DIYers replacing both the sensor and the seal at the same time | Eliminates the need to source parts separately; ensures all sealing surfaces are renewed in one job |
Access the knock sensor through the engine bay or from underneath, depending on where it is mounted on your engine block or intake manifold. Remove the sensor carefully, extract the old seal from the bore, clean the seating surface thoroughly, and seat the new seal before reinstalling the sensor. Tighten the sensor to the manufacturer's specification using a torque wrench — over-tightening can crack the sensor body.