[darknight30]

Ok I apologize ahead of time if this is in the wrong place, and also I am not very good with mechanical details. But here is my problem. My Subaru Forester has 160k miles, and today when I went to start it, it make a horrible knocking/tapping noise coming from the engine, and this is just sitting idle. I had someone look at it and they think it might be the rocker arm?, or a problem with the intake or exhaust valve. Im curious if this sounds right, or if anyone has had a problem like this. My father in law is a mechanic and said I could use his tools etc but Im curious how big of a job Im looking at and would I run in to any other problems tearing the engine apart. Thanks ahead of time. I hope I explained everything ok.

 

[Wormguy]

Does the sound go away as the engine warms up? Has the engine lost power? Is the engine out of oil?

 

[darknight30]

Wormguy thanks for the response. The sound does not go away as the engine warms up, and when I drove it home from across town where I live when I first heard the noise the engine was real sluggish and felt like it was losing power. I checked the oil and there is oil on the dip stick and it all looks normal. Im just hoping my engine isnt toast.

 

[funkymonkey1002]

Has the timing belt ever been replaced?

 

[darknight30]

As far as I know it has not. I bought the car used when it had 130k miles on it. I have looked through all the service records I have and I don't see anything for a timing belt.

 

[Wormguy]

Okay. Probably not piston slap or lack of oil.

Maybe it's a bad bearing inside the timing belt tensioner or the water pump. This would create strain on the belt pulley system and/or (if the belt is already a bit stretched because of age) cause 'slightly off' valve timing, both of which could cause a perceived loss of power. If so you should have the timing belt done as soon as possible, because if a tensioner seizes it's bad news. The shop can also investigate the clicking sound. Usually a timing belt replacement involves changing the tensioners anyways.

You are fortunate that the sound occurs at idle, when the engine's normal noise is at its lowest and you can safely investigate under the hood. Get a 3-ft length of hose. Put one end to your ear and use the other end to localize the source of the sound. Is the clicking sound coming from the front of the engine, or deeper down/back, in the block or heads, or right under a valve cover?

Is the check engine light on?