How to find a good garagePoor garage service

1 Listen to February's Which? car podcast

We took 50 cars, all still within their new-car warranty, to garages around the country, having first inspected them for any pre-existing conditions that a good garage service should spot.

Each garage was rated based on whether the service was carried out in accordance with the manufacturer's schedule, whether the garage spotted the faults we'd introduced and whether it returned the car in a safe condition.

Finally, we checked whether unnecessary work had been recommended or undertaken – thankfully, few garages did this.

Step by step guide to garage faults

A graphic of a car with parts of hte body work cut away

1 Reversing light

Fault missed by 25 out of 50 garages

We deliberately blew one of the reversing light bulbs.
It may not be as safety-critical as other faults, but it indicates a slapdash approach to checking the basics.

2 Spare tyre

Fault missed by 38 out of 50 garages

We reduced the pressure of the spare tyre to a lowly 10psi.

3 Nearside rear tyre

Fault missed by 9 out of 50 garages

We reduced the nearside rear tyre pressure to 20% below the manufacturer's recommended pressure.

We found pre-existing damage, excessive or uneven wear or incorrect pressures on 27 cars in our pre-inspections.

So it's critical that a mechanic inspects the tyres thoroughly at the service. A premature tyre failure could be not just inconvenient – it could be life-threatening.

4 Brake fluid

Fault missed by 26 out of 50 garages

We reduced the level of brake fluid in the reservoir to minimum.

Even a half-competent mechanic should notice this. We wouldn't expect them to top it up without investigating why it's dropped to the minimum level, but a good mechanic will try to diagnose why it's low.

Potential problems to look for include worn brakes (fitting new linings should recover the original level), or a system leak – both should have been reported.

5 Screen wash

Item charged for by 20 out of 50 garages

We filled up the screen wash just before taking the car in to see how many garages charged for it, even though it was already full. Some, but not all, put the bottle of fluid in the car for future use.

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