Visitor

Question for you engine experts. I recently purchased an 88 911 with 75,000 miles on it. PPI checked out great. However, I am getting a low frequency noise (sort of like a rattle/knock) at idle from the lower, front part of the engine. Cannot discern whether it is a harmonic noise from the belt pulley, or something in the engine. Wrench that did the PPI said that these cars can have noisy intermediate shafts and that may be it.

Anyone have experience with the intermediate shaft noise and how to isolate it? Is it a concern?

Thank you.

mikemdd

First, I am not an expert mechanic. However, I can tell you my experience. I have a 1987 turbo with 21K miles on it. I had some minor work done on it and when I got it back, it had an engine "knock" at idle. It was worse (but not bad) as it warmed up. I talked to the mechanic and he said the same thing about the intermediate shaft. He looked at it and noted the the idle had been reduced to about 750rpm. He raised it up to the spec of 900-950 rpm and voila...the noise went away. He said the idle speed is important for many reasons, as these engines are rather finicky. At the lower idle speed, it just wasn't in balance. Anyway, hope this helps.

fixnprsh

996 Turbos have a noisey intermediate shaft, Usualy not these cars unless something has gone wrong, It would be hard to pin it with out being able to listen to it, and I dont want to guess at something and have you get all weird so I would take it to another reputible shop to have them inspect it.