Genuine Audi A3 Timing Chain

Audi A3 Timing Chain Parts and Q&A

• Timing Chain
  06D-109-229-B
  Q: What steps are involved in removing and refitting the timing chain and timing chain tensioner in this work on Audi A3?

  A:

  This job consists of taking out the sump and it commences with taking out the timing cover. Timing chain tensioner rail has to be made free of the chain and the hydraulic tensioner tied by pushing the back end of the rail against the piston into the hydraulic tensioner followed by attaching an appropriate 3.0 mm diameter tool into the holes designed to hold the piston. The tensioner is removed out of the cylinder block and the timing chain is labeled in the direction of rotation to help in the proper re-fitting. When the inlet camshaft sprocket is held in place, both sprocket retaining bolts are loosened with the exhaust camshaft adjuster sprocket bolt being of left-hand thread. The bolts are loosened, the timing chain, camshaft sprockets and exhaust camshaft sprocket shaft are taken out unhooking the chain off the crankshaft sprocket. In order to take the oil pump sprocket off, the plastic cover is removed then the sprocket is held stationary as the retaining bolt is loosened. The chain tensioner spring is disengaged and removed and the mounting bolt is then unscrewed to remove the chain tensioner. The oil pump chain is labeled on direction of rotation, the retaining bolt is removed to remove the sprocket and chain off the crankshaft sprocket and another oil pump sprocket bolt is discarded and replaced with a new one during refitting. The sprocket is removed off the crankshaft with a lug that fits in a groove of the crankshaft journal, and timing chain guides are removed off the engine. Every part is cleaned and checked against excessive wear especially the timing chain and oil pump drive chain, sprocket teeth are checked as well, in this case it is recommended to renew the chain and the sprockets when the engine has high miles. Whenever the crankshaft pulley bolt is removed, then it needs to be replaced. In refitting crankshaft is checked to determine that it is still at TDC before refitting sprocket and engaging lug with the groove to indicate it with respect to the cylinder block so that it can be easily checked. The chain is engaged with the oil pump sprocket making sure that the chain is in the proper position and then placed on the crankshaft sprocket with the new bolt and tightened to the required angle and torque when in position. The chain tensioner of the oil pump is re-fitted with mounting bolt tightened, then with the tensioner spring and cover made of plastic. The crankshaft sprocket must be inspected to align with the TDC mark on the cylinder block and then the sprocket must be re-fitted to the inlet camshaft by inserting a new bolt and tightening it by hand. The timing chain is captured on crankshaft sprocket and on front guide sprocket and inlet sprocket, the exhaust camshaft sprocket is captured on the chain and re-attached to the camshaft with a new bolt also hand tightened. The timing chain tensioner is again fitted and bolts tightened to applicable torque and locking tool removed to release the tensioner is done. TDC marks on crankshaft sprocket and cylinder block, and the marks on the ends of the camshafts are also checked to ensure proper alignment and the sprocket bolts on the camshafts are then tightened to the specified torque and angle at the same time with the camshafts in position. Lastly, the timing cover is re-fitted.