[bimmerlove335]

Hi all,

Recently a noise developed off the front of the engine somewhere. It is a loud knocking sound that is intermittent. Usually on cold start it isn't noticeable but gets worse as I warm the car up. Sometimes the noise goes away completely even when the car is warm. I took it to an indy mechanic who said it was the power steering pump failing, this seemed reasonable.to me based on where I perceived the sound to come from. I had him replace the power steering pump with one that I ordered online that has a lifetime warranty

After I got the car back, the noise seemed to subside for about a day until it came back about the same. Since the noise is intermittent, it appears as if the problem was never solved. When I took the car back to the mechanic, he said the pump that I brought was faulty and that it needs replacing, which I have a really hard time believing. Upon inspection of the old pump, it seems as if the pump was in perfectly serviceable condition. There is no noticeable play that would have caused this sound, and the seal where the pulley attaches is in good shape.

So I have narrowed the problem down to a few components. I believe the problem is either in one of the two idler pulleys, the tensioner pulleys, or the alternator clutch pulley. I am willing to replace all of these components at some point, but right now I really need the car to get to work. I'd prefer not to just take the car to another shop and have them waste a bunch of money buying parts from the local auto parts store. I'd prefer to buy the parts online to save some money and have the shop instal them since I'm so busy working. Just trying to figure out what is wrong right now.

Here is a video of my car. I did have a leaking oil filter housing gasket which was replaced, just so you know.

https://www.youtube.com/watch?v=zG6Biw6VbeQ

The noise sounds worse in the video than in reality. It is definitely coming from the belt area somewhere. The noise seems to decrease as engine rpm increases.

Let me know what you think!! I've tried searching all over the forum for anything similar and that's what helped me narrow it down a little bit, but none of the symptoms others are reporting seem to match mine exactly.

By the way this is my first official post on e90post.com so thanks very much for having me, I've been reading on this forum for quite some time.

[juld0zer]

With engine idling, watch the tensioner. Does it flap wildly?
Also watch the harmonic balancer at idle. Does it shimmy a lot?
Slacken the belt by pushing back the tensioner arm and holding it in place with a drill bit or allen key then wiggle all the pulleys side to side to check for play. Spin the pulleys with a swift motion and listen for bearing noise. Do the pulleys freespin like a skateboard wheel or do they feel a tad stiff as in a little resistance to freespinning?

[bimmerlove335]

Thanks for the reply!!


So I finally got things sorted out. I had a lot of grease on the front of my engine from my leaky oil filter housing gasket which was replaced last weekend. It had been leaking for quite some time and a layer of sludge had built up on the front of the engine. The belt was trashed and really needed to be replaced.

After degreasing the front of the engine and replacing the belt, all noise has subsided. For future reference, to anyone experiencing similar issues, be sure to replace your oil filter housing gasket in a timely manner and dont forget to degrease your engine. Always change your belt if its covered in oil or if worn.