Porsche 996 986 997 987 Boxster Carrera Cayman M96 IMS Intermediate Shaft Bearing Failure: Upgrade Repair Replacement Retrofit Here at Rennaissance Boise!
IMS Bearing Explained
Inside your water-cooled Porsche M96 engine, you have a crankshaft that drives the connecting rods/pistons like everything else. The Intermediate Shaft is a tubular shaped part (see red arrow above)that resides parallel to and just below the crankshaft, which drives the IMS via sprockets and a double-row chain. It's purpose: driving the camshafts and the oil pump. Six-Cylinder Porsche Air-Cooled Engines(see below) have had intermediate shafts since their birth, but none quite like this. The bearing that resides at the sprocket-end of the intermediate shaft rides upon is a sealed steel ball bearing. Over time the oil bath causes the seal to shrink allowing the grease inside the bearing to leak out causing heat and friction to build up leading to bearing failure. That's it. The IMS bearing fails and when it does, causes severe damage to your engine. In some cases, this damage is irreparable. This isn't a case of IF- it's a case of WHEN. What's worse, there's nothing you can do to stop this bearing from failing- but you can replace it before this happens.
Porsche IMS Revealed
The first step in the process is the inspection. We lift the vehicle, run the engine and listen for abnormal noises with a stethoscope. Second, we drain the engine oil through a filter that will seperate particles if present. The engine oil filter is then cut open and both filters are inspected for particulate. If none are found, we proceed with the retrofit and remove the transmission.
This is a closeup of the flywheel side of the engine. The tranmission and clutch assembly have been removed. The circular component in the center is the crankshaft. Note the three-bolt IMS flange just below it. This particular engine has a faulty crankshaft seal which will be replaced during this repair. This is a common find.