What stop-start Mitcham mileage does to a used car
Local driving is slow and interrupted. The Fair Green stretch of London Road is open only to buses and cycles so general traffic uses the one-way system, the Figges Marsh signals queue at peak times, and Carshalton Road pinches over the railway and tram lines by Mitcham Junction. Short journeys in traffic like that never get an engine and exhaust properly hot, which is the single most useful thing to know when the car you are looking at is a diesel that has lived locally all its life.
A diesel particulate filter needs sustained high exhaust temperatures to burn off its soot, and a car that only ever crawls to Figges Marsh and back may have spent years interrupting its regeneration cycles. So on a local diesel we read the soot loading and differential pressure values, check for stored or pending faults in the emissions modules, and look at whether the filter is original or has been replaced or interfered with. We also check oil level and condition, because repeatedly aborted regenerations dilute engine oil with fuel.
The same slow mileage flatters other things unfairly. Brake discs corrode at the edges on a car that is used gently, handbrake mechanisms seize, tyres age out before they wear out, and coolant and brake fluid quietly deteriorate on a car that has barely covered 4,000 miles a year. We measure rather than guess: pad and disc figures, tread depths and tyre date codes, coolant strength and brake fluid moisture content, with a photograph of anything significant.
It is a quick run in. London Road south to the Cricket Green, Cranmer Road to Carshalton Road, then south over the bridge by Mitcham Junction into Hackbridge, about eight minutes. Agree the inspection with the seller first, hold the car with a refundable deposit if you can, and get it here cold. The written report is yours to keep and use, whichever way you decide.