I have a whistling noise coming from my timing chain cover. I thought it was my air pump, but my mechanic found it coming from the timing chain cover. He said it didn't sound like the tensioner was going bad. He didn't know what it was. I've had the car since JAnuary and it's always made the noise. He said that if it has gotten worse since I've had it then it's not something that's about to fail. It does have a set of Dinan cam gears, but I doubt that thats the cause. Does anybody have any ideas? My mechanic, who I trust, said it might cost around $1800 or less. He wouldn't know untill he got in there. The car does have 105k on it.