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Exhaust Pre-Silencer
By OE Match
- Porsche 911 1974-1977 2.7L / 1976-77 3.0 Carrera
- Porsche 911 1978-1983 3.0L / SC
- Porsche 911 1984-1986 3.2L
- Porsche 911 1987-1989 3.2L G50
Securely seal an unused oxygen sensor port with this OE Match Blanking Plug for Oxygen Sensor Hole. Designed for compatible exhaust applications, this plug is used when an oxygen (lambda) sensor mounting hole is present but a sensor is not required for the particular vehicle, exhaust configuration, testing setup or application.
M 18 x 1,5 x 18
23mm in length
Oxygen sensor ports are threaded openings in the exhaust system that normally accommodate a lambda sensor. When the port is not being used, it must be properly sealed. Leaving the opening exposed can allow hot exhaust gases to escape and may permit moisture and contamination to enter the exhaust system.
What This Product Does:
- Seals an unused oxygen or lambda sensor mounting hole.
- Prevents exhaust gases escaping through an unused sensor port.
- Helps maintain the integrity of the exhaust system.
- Protects the threaded sensor opening from dirt and contamination.
- Helps reduce moisture entering through an unused port.
- Allows an exhaust component with an oxygen sensor boss to be used where a sensor is not required.
- Provides a removable solution if an oxygen sensor is required later.
- Replaces a missing, damaged or corroded blanking plug.
- Provides an OE-style solution for compatible exhaust applications.
Symptoms Of Wear Or Failure:
- Exhaust gases leaking around the plug.
- A ticking or blowing noise from the oxygen sensor port.
- Black soot deposits around the plug or threaded opening.
- A strong exhaust smell near the affected area.
- The plug has become loose.
- Visible corrosion or deterioration.
- Damaged or stripped plug threads.
- A plug that can no longer be securely tightened.
- The original blanking plug is missing.
- An oxygen sensor has been removed and the port remains open.
- Heat or exhaust staining around the sensor boss.
Why Replacement Matters:
- An unused oxygen sensor hole should never be left open during normal engine operation. Exhaust gases are extremely hot and can escape through the opening at high velocity, potentially damaging nearby components and creating excessive noise.
- An exhaust leak can also affect the correct operation of the exhaust system. Depending on the location of the unused port and the vehicle's configuration, unwanted air entering the exhaust may also interfere with exhaust-gas measurements or diagnostic testing.
- The threaded sensor boss itself can deteriorate if left exposed. Dirt, moisture and corrosion may damage the threads, making installation of a future oxygen sensor more difficult or requiring repair of the sensor mounting point.
- A loose or damaged plug can produce similar problems. Soot deposits around the port are often an indication that combustion gases are escaping past the sealing surface or threads.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
333660211
The product you are viewing cross references to these numbers
OEMatch Exhaust Pre-Silencer — Flow, Response, Refinement
OEMatch exhaust pre-silencer components for Porsche models support correct exhaust gas flow and sound control, helping to keep everyday road and enthusiast cars feeling well maintained.
- Individual pre-silencers and related fittings for targeted exhaust repairs
- Options suitable for everyday maintenance, upgrades and restoration work
- Made to original-spec dimensions for consistent performance on Porsche applications
OEM (Original Equipment Manufacturer) parts are made by the same company that produced your Porsche’s original exhaust pre-silencer. OE (Original Equipment) refers to parts matching original specifications for the exhaust pre-silencer and may be supplied by alternative manufacturers. Aftermarket parts offer alternative options, sometimes with enhanced features or better value. OEMatch supplies non-OEM exhaust pre-silencer engineered as direct-fit alternatives to OEM parts, made to original-spec dimensions and tolerances for Porsche models.
Exhaust pre-silencers sit between the main exhaust sections and final silencers, influencing gas flow, noise characteristics and overall refinement. Many owners search for genuine or OEM exhaust pre-siliser; these are direct-fit alternatives designed to match the original form, fit and function. When corrosion, cracking or internal deterioration occurs through age, heat cycles or exposure to moisture and road contaminants, pre-silencers can become noisy or develop leaks, affecting comfort and potentially accelerating wear in nearby sections.
- Helps maintain controlled exhaust tone and acceptable noise levels
- Supports correct backpressure characteristics for everyday driving
- Can reduce harshness, drone and resonance when existing units are tired
- Contributes to a cared-for feel, especially on higher-mileage Porsche vehicles
- Heat cycling leading to metal fatigue, seam cracking or warping
- Corrosion from moisture, road salt and short journeys where condensation remains in the system
- Impact damage from road debris or grounding on speed humps and ramps
- Internal baffle breakdown over time, causing rattles or a change in exhaust note
The Importance of Replacing with OEMatch Exhaust Pre-Silencer
Keeping the exhaust pre-silencer in sound condition helps preserve the character of your Porsche while supporting reliable day-to-day use. Replacing deteriorated sections with components made to original-spec dimensions helps the system align correctly, reduces the likelihood of leaks at joints and can make future maintenance more straightforward. For projects ranging from routine servicing to more in-depth restoration, this area of the exhaust is worth assessing carefully.
- Components made to original-spec dimensions for consistent alignment
- Compatible with factory mounting points and typical clamp and flange arrangements
- Suitable for both repair scenarios and planned upgrade work on Porsche exhaust systems
Support & Advice
Fitting exhaust parts can affect noise, emissions and general safety. Installation should be carried out by a qualified technician following model-specific procedures and torque settings. Use suitable fixings and sealing rings where specified, and recheck joints for leaks after initial heat cycles.