Replacing the timing belt and cylinder engine (Audi 100 C4)

Removal

Disconnect the wire from the negative battery terminal. Using the large bolt on the crankshaft sprocket, turn the shaft so that the piston of cylinder #1 is at TDC of the compression stroke. In this case, both valves will be closed and the "0" mark on the flywheel will be aligned with the pointer on the casing. If the belt has not come off, the timing mark on the back of the camshaft sprocket should be aligned with the upper left edge of the valve cover.

Remove the upper and lower timing belt covers.

While holding the large hex nut on the tensioner pulley, loosen the smaller pulley lock nut.

Turn the tensioner counterclockwise to relieve tension on the timing belt.

Carefully pull the toothed belt off the sprockets and release the belt.

Installation

If the engine has turned over, use the large bolt on the crankshaft sprocket to rotate the engine until the No.1 cylinder piston is at TDC on the compression stroke. At this point, both valves will be closed and the "0" mark on the flywheel will be aligned with the pointer on the housing. Rotate the camshaft until the timing mark on the back of the camshaft sprocket is aligned with the upper left edge of the valve cover.



Install the crankshaft pulley and check that the mark on the pulley is aligned with the mark on the intermediate shaft sprocket.



If it does not align, rotate the intermediate shaft until the marks align.

Caution: If the timing marks do not align when the piston of cylinder 1 is at TDC of the compression stroke after installing the belt, the valve timing will be incorrect. This may result in poor performance and engine damage.

Remove the crankshaft pulley. Note the position of the pulley on the crankshaft sprocket so that it can be installed in the same position. Hold the large nut on the tensioner pulley and loosen the small nut on the tensioner pulley. Turn the tensioner counterclockwise to loosen it and install the timing belt.

Pull the toothed belt onto the sprockets and adjust the belt tension. The tension is normal when the belt can be twisted 90° in the middle between the sprockets of the camshaft and intermediate shaft.

Install the crankshaft pulley. Tighten the mounting bolts to 2Nm.

Install the upper and lower timing belt covers.

Test drive the car.

(The original publication in its entirety is posted on the website: «AudiManual.ru»)