07 Audi A3 Timing Belt Tension Changing while rotating motor.

Hey everyone,

I've been working with this 07 A3 off and on for a lean condition and found a odd problem with the timing belt. So, I'm looking for some insight before I proceed.

2.0 FSI, 183k miles. Unknown service history.

I noticed the timing belt has been wearing a groove on the top cover. The belt was loose, and the tensioner marks indicated that. I started to rotate the motor, from the crank pulley, clockwise, to TDC. Verified tdc with a screw driver and timing marks, and now the belt is over tightened. Spin the motor 90'ish degrees, the belt is loose again. I can feel the difference in resistance when turning the motor when the belt is tight or loose. Theres also this "tick" sound when turning the motor when it starts getting tight. The motor has been running like this. I've done plenty of timing belts, but never really had this problem before. I have more experience with Porsche than these cars.



Some insights would be helpful, and hopefully someone has ran into this problem before.

Thanks in advance.

Bent camshaft?

MartinsX said:

Bent camshaft?

Click to expand...

Agreed. Also seen a sheered crank keyway cause an eccentric wobble. Could explain the tick noise, or a hairline crack in the cam itself. Run the engine and examine the wobble/hop on the crank pulley. with and without the vibration damper installed + wobble/hop on the cam gear

*Also. One time and one time only ive personally had a FSi A4 come in with a snapped exhaust camshaft. Snapped flush with the last bearing journal on the head.