Genuine, OEM or aftermarket parts: what to fit and when

When a garage quotes for a repair, you'll often be offered more than one type of part. Here's what the terms mean.

• Genuine: sold by the vehicle maker in its own packaging. Usually the most expensive, with a guaranteed fit.
• OEM (original equipment manufacturer): made by the company that supplies the vehicle maker (for example Denso, Aisin or NGK for many Japanese cars), sold in its own box. Often the same quality as genuine for less money.
• Aftermarket: made by other companies. Quality ranges from excellent to dangerous.
• Used (ex-Japan): second-hand parts from dismantled vehicles. Fine for some items such as body panels and mirrors; risky for wear parts.

Where not to save money

Brake pads and discs, brake hoses, tyres, steering and suspension joints, timing belts and gearbox fluid. A failure here is either dangerous or far more expensive than the saving.

Avoiding fakes

• Buy from established dealers and ask for a receipt that names the part and brand.
• Be wary of prices far below everyone else's.
• Ask your garage to give you the old parts back; it shows they were really replaced.

Record the part names and brands in your CarLog service record, so you know exactly what was fitted next time.