At the recent Automechnika trade event, OE and aftermarket supplier of both primary and auxiliary drive systems components, Dayco, was offering some highly relevant technical advice on common fitting issues. 

When fitting problems occur, Dayco reacts quickly to diagnose why they are occurring and then highlight the issues to workshops and technicians. One such area is with belt replacement on two very popular vans in Ireland, the Citroën Berlingo 1.6 HDI and Peugeot Expert 2.0 HDI. 

There is a two-stage tensioning process that must be carried out, when replacing the timing belt on the 1.6 and 2.0-litre HDI engines, that are widely used by Fiat, Ford, PSA and Opel, in many of their popular model car and van applications. Although the consequences of not following the procedure may not be immediate, because both units are of an interference design, the effect of a subsequent belt failure is likely to be catastrophic to the engine.

Looking first at the 1.6, in this instance in a Berlingo, the process is as follows: once the replacement belt has been installed and is taut between the sprockets, the new tensioner must be turned anti-clockwise, until the pointer is in its first position and the bolt tightened to 30Nm. After removing the locking/aligning tools, the crankshaft must be turned clockwise six complete rotations and the tensioner reset to its second, operational position and the bolt retightened to 30Nm. The crankshaft then requires two more clockwise rotations to the setting position, where the locking/aligning tools should be refitted and the position of the tensioner checked again, to ensure it is aligned correctly. If it is not, the entire procedure needs to be repeated until it is correct.

Following a similar pattern, the 2.0, which in this example is fitted to an Expert III, requires the new tensioner on the replacement belt to be moved anti-clockwise and set to its initial position and tightened to 21Nm. The technician then has just five minutes to remove two of the locking tools, refit the lower belt cover, crankshaft position sensor, crankshaft pulley, bolt and spacer and tighten to 50Nm, and then remove the final three locking/timing tools, rotate the crankshaft clockwise six complete turns to the setting position, refit the three tools, slacken the crankshaft pulley and turn the tensioner clockwise until the pointer aligns with its operational position and retighten to 21Nm. If however, the pointer passes this position, the tensioning procedure must be repeated until it aligns.

Dayco say what these examples demonstrate, is that even a scheduled service requirement on comparatively common engines, requires technicians to follow a specific procedure and not just apply a general rule.

It is for this reason that Dayco recommends those with the responsibility of undertaking the work to not only use OE quality replacement components, but also allow themselves five minutes of preparation before they start, to check the technical data that the workshop subscribes to and find the correct, engine specific procedure they need to follow to ensure they can complete the job successfully, first time.

For more information visit www.daycoaftermarket.com