Primary (timing) Drive System
The diesel engines used extensively across the 159 range are fitted with a Dayco High Tenacity (HT), or ‘white’, timing belt as its original equipment (OE) fitment. These units also feature a water pump that is integrated into the timing drive system and driven by the HT timing belt. Therefore, workshops undertaking either a water pump or timing belt replacement, need to realise that only by fitting a Dayco HT timing belt kit can they be assured of a genuine like-for-like replacement.
Technicians should follow industry best practice and ensure that they replace the water pump when the timing belt is being replaced and vice versa. Both of these components cover the same mileages, so replacing both at the same time is the most cost effective option in the long-term and provides motorists with much needed peace of mind following a vehicle repair.
The petrol variants use a combination of belt and chain driven primary drive systems, so check the Dayco’s web catalogue for the correct kit reference for each application.
FEAD (front end auxiliary drive) System
Dayco was also the OE auxiliary belt and component supplier for both the diesel and petrol engines in the 159 range.
Despite being subject to inevitable wear and tear during the lifespan of the engine, the FEAD system has not traditionally been subject to any particular maintenance or replacement schedule. However, Dayco believe it is important for technicians to regularly examine all the components within the FEAD system.
Although it may not directly be a safety critical component, the auxiliary belt in the 159 drives so many vital components – alternator, power steering pump, air conditioning compressor etc. – and even if its failure does not directly stop the vehicle, it could certainly leave the driver without power to some parts of the vehicle that could make it in effect, un-driveable.
Dayco provides a small tool named the ‘a-WEAR-ness gauge’ with which technicians can quickly and accurately carry out three visual checks (wear in both the profile and the depth of the belt groves, plus any cracks in the belt) that will clearly reveal the condition of the belt.