Auxiliary Belts (AC & Alternator) - Focus XR5 / MK2 RS

Dayco Auxiliary Drive Belts

A quality replacement set of Dayco Poly-V auxiliary belts designed to provide reliable power transmission to the engine's accessory systems. Dayco belts use high-quality EPDM compounds designed for flexibility, heat resistance, low noise and long service life. The multi-rib design also provides excellent contact with the pulleys while helping minimise slip.

These belts are sold separately or in a pair:

• A/C Belt: Runs from the crankshaft pulley to the A/C compressor.
• Alternator Belt: Runs from the A/C compressor pulley to the alternator.

While the two belts are very similar in length, they are different belts and are not interchangeable. Make sure you select the correct belt for your application.

Official Service Interval:

The recommended service interval is 150,000 km or 10 years, whichever comes first. However, given the potential consequences of an auxiliary belt failure on these engines, earlier replacement is recommended.

Personally, I would consider replacing the belts around 80,000 km or 5 years, particularly on performance or enthusiast driven vehicles. The condition of the belt should always be taken into consideration rather than relying solely on mileage or age.

Inspect the belts regularly for:

• Cracking or hairline cracks
• Frayed or splayed belt fibres
• Damaged or missing ribs
• Rib deterioration or excessive wear
• Glazing or other signs of deterioration

Modern EPDM belts can wear without showing obvious cracking, so checking the rib profile and overall condition is important.

Why replacing the belts matters

On these engines, a failed or shredded auxiliary belt can do considerably more than simply stop the alternator or A/C from working. Belt debris can become trapped around the crankshaft pulley and make its way into the timing belt area. This can cause the timing belt to jump teeth or become damaged, potentially resulting in severe engine damage including bent valves.

For the relatively low cost of a new set of auxiliary belts, regular replacement is cheap insurance against a potentially very expensive engine repair.