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IMS Bearing Replacement: What Else Should Be Serviced on Your Porsche Boxster, Cayman, or 911?

Most Porsche owners know that replacing the IMS bearing (intermediate shaft bearing) is critical for Boxster, Cayman, and 911 996 models. But simply replacing the bearing isn't enough. Whether your Porsche has the earlier serviceable IMS bearing or the larger non-serviceable version found in later 997 engines, it's essential to take a comprehensive approach.

Unfortunately, we’ve seen too many shops competing on price alone, offering cut-rate IMS jobs by cutting corners. In some cases, we've even seen reused oil, skipped filter changes, or incomplete inspections—all to save money. If you want your engine to last, this is not the place to cut costs.

Here’s a breakdown of 12 often-overlooked but absolutely critical items that should be addressed when servicing your Porsche’s IMS bearing.

✅ 1. Water Pump and Thermostat

A failing water pump can lead to catastrophic overheating and even cracked heads.

Replacing the thermostat with a low-temperature unit helps keep your engine cooler, reducing wear and stress on internal components.

✅ 2. Air/Oil Separator (AOS) and Vent Lines

A failed AOS can cause hydrolock and severe engine damage.

Aging vent lines often crack, causing vacuum leaks. Use a manometer to assess AOS performance.

✅ 3. Oil Filler Tube

These become brittle and crack with age, causing vacuum leaks that affect fuel trims and engine efficiency.

A smoke test is the most effective way to detect hidden leaks.

✅ 4. Rear Main Seal (RMS)

Always use a genuine Porsche RMS—aftermarket seals often don’t seal as reliably.

Most shops replace the RMS during IMS service, but confirm they’re using OEM parts.

✅ 5. Clutch, Pressure Plate, and Flywheel

Even if your clutch has life left, replacing it during IMS service saves labor costs down the line.

The dual-mass flywheel often needs replacement—deflection testing is required, but replacing it now can avoid future headaches.

✅ 6. VarioCam Wear Pads (5-Chain Engines)

Applies to 1997–2002 Boxster and 1999–2001 911 (996) models.

Even without a CEL, worn wear pads can throw cam timing off—anything over 4° deviation means they need to go.

✅ 7. Bore Scoping and Sump Inspection

Bore scoring affects 3.4, 3.6, and 3.8L M96/M97 engines.

Drop the sump and scope the cylinders through both the spark plug holes and the bottom end.

Even a quiet-running engine may already be in trouble.

✅ 8. Spark Plugs and Ignition Coils

Prevent misfires by replacing plugs and coil packs.

For 5-chain engines, also replace the spark plug tubes to avoid oil leaks.

✅ 9. Fuel Injectors

Aging injectors can cause poor fuel trim and contribute to bore scoring.

An ECU interrogation as part of the IMS pre-qualification procedure can uncover hidden fueling issues.

✅ 10. Lifters

Lifters can become noisy due to poor maintenance.

Misdiagnosed bore scoring is often blamed on lifter noise—bore scoping confirms the true cause.

✅ 11. Timing Chain Tensioners

Bad tensioners cause chain rattle or startup noise.

Easy and inexpensive to replace while the engine is out or during major service.

✅ 12. Engine Oil and Used Oil Analysis

Regular oil changes with Driven DT40 every 6 months or 5,000 miles is key.

Used oil analysis from Speediagnostix offers insights into engine health before symptoms appear.

Don’t Cut Corners—Go With a Certified Porsche Specialist

The IMS pre-qualification procedure, developed by Flat 6 Innovations and used by LN Engineering, is the gold standard in ensuring an engine is safe to receive an IMS Retrofit or IMS Solution. Skipping this step puts your entire investment at risk.

Because IMS replacement is labor-intensive and often requires transmission and engine removal, it’s only smart to address these other wear items while you're “in there.” Yes, it may cost more up front—but it’s far less expensive than an unexpected rebuild.

If you don’t have the equipment, experience, or confidence to perform this service, trust a certified LN Engineering installation partner.