Your A to Z of motoring gobbledygook
Deadlocks
These prevent a door from being opened even if someone breaks the glass and reaches inside. Once activated, deadlocks can only be re-opened with the car's remote control or key.
Delamination
This is the process where a tyre that is faulty, or has been run under-inflated, may break down, causing its tread layer to become separated from the casing.
Diagnostics
This is the process by which dealers or garages plug their computer into the car's engine-management system to trace and repair faults.
Direct injection
A more efficient way of burning fuel by injecting it directly into the combustion chambers of an engine rather than a separate pre-combustion chamber. It is most common in diesel engines, although direct injection petrol engines are becoming more widely available.
Directional
Tyre tread patterns which vary from one side of the tread to the other, ie, they are not symmetrical. If these tyres are non-directional they must be fitted with the outside sidewall on the outer face of the wheel. If they are also directional, they will also be specific to the left and right sides of the vehicle.
Driveshaft
The turning shaft which delivers engine power from the gearbox to the wheels of a car. It can be expensive to put right, so check it on any used car test-drive. In front-wheel drive cars, put the steering on full lock and pull away. If you feel a 'clunk' then the shaft could be worn.
DVLA (Driver and Vehicle Licensing Agency)
The Government body that issues driving licences and registers vehicles for use on UK roads. Records of both are kept so that drivers and vehicles can be traced, for law-enforcement purposes or safety-related recalls. The DVLA collects road tax and also sells number plates.
