2002 Porsche Boxster S IMS Bearing Replacement Parts: A Complete Guide

The 2002 Porsche Boxster S, like many M96-engined Porsches, is known for a potential weak point: the intermediate shaft (IMS) bearing. Replacing this bearing is a proactive maintenance step that can prevent catastrophic engine failure. If you're planning an IMS bearing replacement on your 2002 Boxster S, understanding the specific parts needed and the options available is crucial. This guide covers the essential parts, aftermarket improvements, and practical advice for a successful repair.

What Is the IMS Bearing and Why Replace It?

The IMS bearing supports the intermediate shaft that drives the camshafts and water pump. In early M96 engines (1997–2005), a single-row ball bearing was used, which had a tendency to fail over time. The 2002 Boxster S uses the 3.2L M96.26 engine, which originally came with a single-row bearing (part number 996-105-122-01-OEM). Failure can lead to metal debris contaminating the oil system, potentially ruining the engine. Replacing the IMS bearing with an upgraded part is a common preventative solution.

Essential Parts for the Replacement

When overhauling the IMS bearing on a 2002 Boxster S, you'll need more than just the bearing itself. The job requires access to the front of the engine, which means removing the transmission and clutch. Therefore, many owners combine IMS bearing replacement with other maintenance items. A typical parts list includes:

IMS Bearing Upgrade Kit

• LN Engineering IMS Retrofit (Dual Row Pro) – The most popular aftermarket solution. LN Engineering offers a dual-row ceramic hybrid bearing that fits the M96 engine. For the 2002 Boxster S, you'll need the specific kit designed for single-row to dual-row conversions. This kit includes the bearing, an O-ring, and sometimes a new threaded retainer. It is known for significantly improved reliability.
• Pelican Parts IMS Bearing Kit – Some vendors offer complete kits with the bearing, seal, and necessary hardware. Ensure compatibility with your engine version.
• OEM Replacement Bearing – Some owners choose to install a new single-row bearing to save cost, but this does not solve the underlying design issue. Most experts recommend upgrading to a dual-row solution.

Clutch Kit

Since the transmission must be removed, it is wise to replace the clutch, pressure plate, and release bearing. A standard clutch kit for the 2002 Boxster S (e.g., SACHS or Luk) is sufficient unless you plan to increase power. The clutch fork and pivot pin are also worth inspecting.

Flywheel & Pilot Bearing

• Dual Mass Flywheel (DMF) – The original flywheel is a dual-mass design. It can be reused if within spec, but many owners convert to a lighter single-mass flywheel for better throttle response. If you stick with DMF, consider replacing it if worn.
• Pilot Bearing – Always replace the pilot bearing. It's inexpensive and failure can cause transmission issues.

Seals & Gaskets

• Rear Main Seal (RMS) – Also known as the lower oil pan seal or the main seal. The RMS tends to leak on higher-mileage engines. Replacing it during IMS bearing service prevents future labor. Use an OEM or aftermarket reparation seal (e.g., a newer version from Porsche).
• Oil Return Tube Gaskets – The oil return tubes under the cam covers often seep. This is a good time to replace the tube O-rings.
• Crankcase Sealant – You'll need a high-quality anaerobic sealant (e.g., ThreeBond 1215 or similar) for the crankcase halves if you separate them.

Other Consumables

• Oil filter and engine oil – After the repair, change the oil and filter to remove any contaminants.
• Coolant – If the water pump is driven by the IMS (not on all early M96), you may need coolant. However, the 2002 Boxster S water pump is separate; still, it's a good idea to flush coolant if not done recently.
• Bolt kit – Many bolts are single-use (torque-to-yield). Obtain a bolt kit for the flywheel, pressure plate, and any other critical fasteners.

Part Selection Considerations

Single-Row vs. Dual-Row

The original single-row bearing is the failure-prone design. Dual-row bearings have larger contact area and use ceramic balls, drastically reducing failure rates. For the 2002 Boxster S, the LN Engineering Dual Row Pro is the gold standard. Some budget options exist, but aim for a bearing that includes a grease-filled, sealed design to prevent oil starvation.

OEM vs. Aftermarket

Aftermarket solutions like LN Engineering have been used in thousands of Porsches with excellent reliability records. OEM parts (new single-row) are available but not recommended for long-term peace of mind. If you plan to keep the car, invest in the upgrade.

Complete Kit vs. Individual Parts

Some suppliers sell a complete IMS bearing replacement kit that includes the bearing, RMS, and other gaskets. This can simplify ordering and ensure you have everything needed. Pelican Parts and other specialty retailers offer such bundles.

Installation Tips and Pitfalls

Replacing the IMS bearing on an 2002 Boxster S is an extensive job that typically requires:

• Removing the rear bumper, exhaust, and transmission.
• Accessing the IMS through the flywheel opening.
• Using a special tool to remove and install the bearing (most kits include a tool or recommend one).
• Properly torqueing the new bearing retainer (often requires a high-strength Loctite).

Common Mistakes:

• Not replacing the RMS while the flywheel is off.
• Reusing the old flywheel bolts (they stretch and must be replaced).
• Failing to properly seat the IMS bearing pilot tool, causing misalignment.
• Over-tightening the IMS bolt, which can strip the threads in the aluminum engine case.

If you are not experienced with Porsche engine work, consider having a professional shop perform the replacement. The parts cost is typically $500–$1,500 depending on options, plus labor (10–15 hours).

Final Recommendation

For a 2002 Porsche Boxster S, the most reliable IMS bearing replacement part is the LN Engineering Dual Row Pro bearing kit. Pair it with a quality clutch kit (SACHS or Luk), a new rear main seal, and fresh fluids. While the upfront cost is higher than a simple single-row swap, the peace of mind and reliability make it the best choice. Avoid cheap no-name bearings and always source from reputable Porsche parts suppliers. If you drive your Boxster S regularly or plan to keep it long-term, this upgrade is essential.