Why Fiveways traffic blocks Alfa JTDm particulate filters
A diesel particulate filter traps soot and burns it off during a regeneration, which needs the exhaust hot for a sustained period. Croydon rarely offers that. A trip from Fairfield across the Croydon Flyover and Duppas Hill Road, then a wait at Fiveways where Purley Way meets the A232, involves more queuing than driving, and a regeneration that starts is often interrupted before it finishes.
For a Giulietta or 159 2.0 JTDm, that pattern leads to a DPF warning light, then a loss of power and eventually limp mode. It also has a side effect many owners do not expect. During regeneration, extra fuel is injected to raise exhaust temperature, and if the process keeps being interrupted, some of that fuel ends up in the engine oil. The oil level rises, the oil thins, and the car may call for an oil change well ahead of schedule.
When your Alfa comes in, we read soot loading, differential pressure and regeneration history in live data to see whether the filter is blocked or whether a faulty sensor is misreporting it. Depending on what we find, a supervised regeneration may clear it, or the filter may need cleaning or replacing. We check the oil level and condition at the same time, change it with oil to the correct Fiat 9.55535 specification if diluted, and look at the EGR system, which often plays a part. We explain what caused the problem so you can reduce the chance of it coming back, for example with a regular longer run out past Lloyd Park and beyond.
From the town centre the route runs over the Croydon Flyover to Fiveways, along Croydon Road past Beddington Park and north up London Road to Hackbridge, about 15 minutes, or longer at peak. You get the price in writing before we touch the car, and any repair is covered by our 3-month workmanship warranty.