nzskater

I'm an owner of a 997.1 2006 911TT. I noticed it last weekend after driving for around 20 minutes. At the time it faintly appeared at around 2200rpm, and increased in frequency relative to the increase in rpm. After driving home I tried to recreate it but failed.

Let it cool down, drove again the next day and couldn't recreate. Haven't driven much this week, but today took it to work and it appeared after warming up. This time noticeable at idle, so took the opportunity to record.

I've recently had a new drive belt installed as part of a scheduled service. Thought it was teething/wear in or some such, but it doesn't sound like it's coming from the belt. Hard to tell from the video but it sounds like it's somewhere in the front right hand side. Have any of you had or heard anything similar?

speed21

It's definitely a pulley related sound and more than likely alternator imo.

Terry Adams

There was on the 993 a tension adjusting roller that sounded just like this when worn out. I don't recall lubricating the roller to fix it.

fskof

+1 I would pull the belt off and inspect every pulley. There is a DIY here on how to pull the belt off. It could be something as simple as a idler pulley or it could be a water pump.

nzskater

Thanks guys. Given the dealership just replaced the belt (few hundred km's ago) I'm going to take it back and ask them to check it over. Suspect it's a tension related issue given the feedback you've given. Hoping it's not the water pump, imagine that's a major to get access to and replace.

L_perm

Actually, the water pump is not too bad--some around here have DIY'd it. It sits right behind the muffler on the bottom of the engine.

I'd guess it's your idler pulley.

LP

Macster

Have the engine checked by a pro tech, but my WAG is the diagnosis will be the idler roller bearing next to the power steering pump.

The one on my 996 Turbo got noisy and was replaced.

Note if the new serpentine belt has a sharp edge the belt is rubbing on the side of a pulley and this suggests an accessory drive with bearing play.

The accessory drive that most often develops play is the water pump but with the belt off the tech will (should!) check every accessory drive pulley for any excessive play.