Timing belt replacement - Vauxhall Astra H 1.7 CDTi diesel
Before carrying out any work,disconnect the battery earth cable.It is important that belt installationis performed on an engine atambient room temperature. Always turn the engine in the normal direction of rotation only (unless advised otherwise by the OEM fitting instructions); recommended manufacturers torque values should always be used. It is recommended to change the tensioners and the pulleys when replacing the cambelt.
A two-post ramp is ideal for carrying out the replacement and it is vital that the appropriate timing belt replacement tools are used. If the vehicle is equipped with alloy wheels then chances are it’ll have locking wheel nuts/bolts, so it’s a good idea to locate the adapter key for these before you start.
Open the bonnet and lift off the engine cover. Undo the jubilee clip securing the air filter housing to the inlet manifold and disconnect the MAF sensor (pictured below).
Remove the air filter housing by lifting it with a slight tug, making sure you lift out the smaller pipe at the front. Disconnect the electrical connectors near to the timing belt cover and unbolt the harness conduit (pictured below).
Unclip the pipe running in front of the cover and stow it to one side. Unclip the conduit by lifting the plastic tab and stow the whole assembly to one side. Slacken the water pump pulley bolts for easier removal later on.
Support the engine and remove the complete engine mounting bracket. Unbolt and remove the remaining timing belt covers and align the markings on the crankshaft (pictured below), camshaft and fuel pump (it may be necessary to rotate the engine up to six turns to do this).
Once aligned use an M6 bolt (Fig 4) to lock the camshaft and a M8 bolt (Fig 5) to lock the pump. Undo the camshaft sensor to allow enough clearance to remove the belt (Fig 6). Slacken the tensioner bolt and, while holding the tension off the belt, remove the timing belt, tensioner and idler pulley.
Fit the new tensioner and idler making sure the fixing bolts are replaced. In some cases the design of the new idler may be different (pictured below) to the original item removed.
This is completely normal as a new part was introduced to replace the older style pulley. Tighten the idler to the correct torque setting but leave the tensioner in the de-tensioned.