My car has a potentially troublesome ‘wet' timing belt. Should I sell it?

Telegraph

22-07-2025

I have owned my nine-year-old Citroen C3 Picasso from new. It is in near perfect condition, has only done 31,000 miles and has always been serviced by a main dealer. I have read your warnings about 'wet' timing belt issues so I'm changing the belt of my car ahead of schedule as a precaution. I would like to get a few more years of use – but should I now cut my losses and move on? Just how disaster-prone is this engine?
– IS
Dear IS,
The issues surrounding 'belt-in-oil' or 'wet' timing belts apply to Citroën, Peugeot or Vauxhall models with 1.0- or 1.2-litre Puretech petrol engines.
Long story short, the engine was designed with a timing belt (which ensures the valves and pistons work in sync) that runs in oil, the idea being to add lubrication, reduce friction and improve fuel economy.
However, the lubricant can break down the rubber of the timing belt; while the oil used in these engines is supposedly formulated to prevent this, it doesn't always do so. Meanwhile, any deviation in the oil's specification (which can include dilution or degradation if not serviced in time) can reduce the level of resistance it offers.
When the belt starts to deteriorate, it's not only its integrity at risk; minute particles of rubber are deposited in the oil. These can get caught in the oil filter and pick-up, resulting in blockages and, in extreme cases, oil starvation.
This, it goes without saying, can be catastrophic. But while cases of belt degradation in cars that have been serviced meticulously still happen, they are rarer; if your car has been serviced on schedule by a Citroën dealer (therefore using the correct oil), you stand a better chance, especially given its low mileage.
Even so, changing the belt ahead of the recommended interval is a good idea. I would suggest that you ask the garage to check the condition of the old belt, to see how badly it had degraded. As an extra precaution, you could even ask them to remove the sump and inspect the oil pick-up and clean it if necessary.
If the timing belt is in good nick and your oil system looks clean, I would suggest there's minimal risk of increased engine wear. If not, you can decide on that basis what you want to do with the car.
Either way, the good news is that the new timing belts Citroën is fitting are made from a tougher compound of rubber that's far more resistant to the sort of degradation that has caused the issue thus far.