I am helping a friend whose 1999 4-cylinder Camry just started a making really loud knocking, diesel-like noise. It also sounds like the timing belt is flapping against the inside of the timing belt cover. I took the timing belt cover off and found that there is 1.25 inches of free play in the belt. I don't know enough about this engine type (nor does the manual indicate) to know if this is okay. I have a picture showing the free play at http://www.dnsppp.net/nmills/camry.

Thanks in advance for your replies.

Niles

I am helping a friend whose 1999 4-cylinder Camry just started a making really loud knocking, diesel-like noise. It also sounds like the timing belt is flapping against the inside of the timing belt cover. I took the timing belt cover off and found that there is 1.25 inches of free play in the belt. I don't know enough about this engine type (nor does the manual indicate) to know if this is okay. I have a picture showing the free play at http://www.dnsppp.net/nmills/camry.

Thanks in advance for your replies.

Niles

The number 1 idler pulley should have both a bolt adjustment and internal spring adjustment to keep the belt tight.

If you two don't know what you are doing, you need a service manual.