Not_So_Fast_Eddie

Ok so it's my turn to rant now. My timing belt was replaced January 2013. I've never had this issue before hand and it's only developed since its gotten cold out. There is a rattling coming from the front of my cars engine and I spoke with the mechanic who did the Timing belt and he figured it was the left cooling fan. Which did make sense because that day the noise started right at the same time the fan kicked in.

Well tonight it's 9F outside and I was aligning my headlights. I had the engine on to prevent me from killing the battery and the noise came back. I thought it was odd that the cooling fan kicked in at idle so the first thing I checked was to see if the fan was on but lo' and behold it wasn't. It seems to be coming from right around the air intake which if I remember right is also the similar location of the timing belt tensioner.

I guess my only option is to call up the garage again, horrible timing as my warranty with them expires in 2 days and the car has no headlights or insurance right now. Here's a video of the sound the day before I spoke to the mechanic the first time.
First time

Tonight

MyNameIsEarl

This reminds me of my episode when I went driving 300 miles to nowhere one night. Try turning off your AC compressor, if the sounds stops, you know what the problem is. Your compressor might be going, going, gone bad.

Not_So_Fast_Eddie

Hey Earl I tried testing for the noise again today. I couldn't reproduce the noise even after letting the car warm up to full temp and idle longer after that. The whole time though the AC unit wasn't engaged, I tried to engage the AC compressor but it just wouldn't kick in. I tried front defroster, ac on, even heat for the hell of it. Still nothing would start it. I've never had the AC fail to kick in before but it could be related to it being 3F outside.

If I can get the ac to kick in and the noise comes back then you've just solved the problem. Hopefully I'll find out soon.

Not_So_Fast_Eddie

Alright managed to get the AC to kick in. The sound isn't caused by the AC. It comes along during idle around 450RPM.

I made another video of it testing the Alternator, AC tensioner, and power steering pump (in that order). I didn't test the AC clutch as it sounds higher up than that.

http://www.youtube.com/watch?v=fbj_k7jRzVo

MyNameIsEarl

Sorry my tip didn't work! I'm not sure what else to tell you. Good luck! Keep us posted.

Not_So_Fast_Eddie

Well some good news. My Dad helped out big time and figured out its probably the idler pulley. The idler pulley bearing has a slight rattle to it and feels loose. There's also no grease in the bearing so it has to be replaced. Hopefully its the source of the rattle.

Best part of all is the replacement bearing is only 11 bucks with free 2 day shipping!