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Dear Sir, After only ever owning air-cooled Porsches, I’m now considering a 996 generation as a bit of a daily driver and also weekend fun. I’ve read lots online about IMS bearings, but conjecture seems to differ when it comes to deciding which years of factory bearings are most susceptible to problems. Can you provide a definitive answer? Also, which is the best aftermarket IMS to fit as a replacement?

Richard Bellingham

The famous IMS returns! To be definitive to make sure your car has the later, ‘larger nut’ IMS, you need to check your engine number, but as a general rule of thumb it’s the ’06 model year cars onwards which have the later IMS shaft bearings, with the earliest 997s still being vulnerable. 911s from 2005 and older usually have the early, smaller nut, single/twin row bearings unless it’s had a replacement engine or repair somewhere in its life. These can be prone to failure. So, M96 engines and early M97 engines are susceptible. As to which is the best one to fit to replace the factory bearing, I’m not sure there is a ‘best’ as all solutions have their pros and cons. We at Bahnsport recommend the EPS cylindrical roller bearing, which comes with a five-year warranty.