Top 10 causes of commercial vehicle breakdowns

Data from the RAC’s technical analysis team shows there is a three-in-10 chance that commercial vehicles will break down on an annual basis.

Of the hundreds of thousands of business vehicles protected by the RAC, 31% are expected to suffer a breakdown this year, based on an analysis of call-outs in the first quarter of 2019.

The amount of time a business without pre-arranged breakdown cover in place would lose when one of its vehicles breaks down could range from an hour or two, to a full day lost. This would depend on how easy it is to get a mobile mechanic to attend or whether the vehicle would need to be transported to a garage for repair.

The most common cause of a breakdown.

The most common RAC business call-out relates to batteries, whether that’s simply a flat battery or one that’s reached the end of its life. In total battery issues equate to 18% of all RAC breakdown jobs for businesses.

Tyres are responsible for generating the second biggest volume of call-outs, making up 13% of all breakdowns. And, with many vehicles now not having a spare wheel, a significant number of these will be ‘puncture no spare’ jobs which would typically be very difficult for a business to get fixed without the support of a breakdown company.

Fortunately, the RAC is well equipped for this situation with every patrol carrying a ‘universal spare wheel’ designed to fit the majority of cars and vans on the road.

Clutch problems complete the top three most common business vehicle breakdowns seen by RAC patrols. While only 5% of RAC business call-outs relate to clutch faults they usually require recovery to a garage for repair.

RAC breakdown data results

According to RAC data based on call-outs during Q1 2019, the top ten reasons for the breakdown are as follows:

Rank	Top RAC SME breakdown call-outs	%
1	Battery	18%
2	Tyres	13%
3	Clutch	5%
4	Alternator	4%
5	Engine mechanical	3%
6	Starter motor	3%
7	Fuel – diesel contamination	3%
8	ECU – engine management	2%
9	Road traffic accident	2%
10	Gearbox - manual	2%

Battery (18%)

Battery breakdowns are common and can be caused by leaving lights or electronics on when the engine is off, a faulty charging system, or an old battery that needs replacing. Symptoms include the car not starting, dim headlights, or the battery warning light on the dashboard. RAC patrols can test your battery, jump-start it if it's flat, or replace it if needed, getting you back on the road quickly.

Tyres (13%)

Tyre issues often result from punctures, worn tread, or incorrect tyre pressure. Symptoms include a flat tyre, reduced traction, or the car pulling to one side. RAC patrols can replace your flat tyre with your spare, provide a temporary repair, or arrange for a new tyre to be fitted if necessary.

Clutch (5%)

Clutch problems are usually caused by wear and tear, especially in stop-start traffic. Symptoms include difficulty changing gears, a slipping clutch, or a spongy clutch pedal. RAC patrols can assess clutch issues and perform temporary repairs to help you reach a garage for a full fix.

Alternator (4%)

The alternator charges your battery and powers electrical systems when the engine is running. Faults can be due to wear and tear or electrical issues. Symptoms include dimming lights, electrical failures, and the battery warning light coming on. RAC patrols can test and, in some cases, replace your alternator at the roadside or ensure you get to a garage safely.

Engine mechanical (3%)

Engine mechanical issues can range from overheating to problems with the timing belt or head gasket. Symptoms include unusual noises, smoke from the exhaust, or a sudden loss of power. RAC patrols can diagnose engine problems and perform minor repairs at the roadside, or arrange for your vehicle to be towed to a garage for more complex issues.

Starter motor (3%)

A failing starter motor means your engine won’t turn over, leaving you stranded. Causes include electrical faults or wear and tear. Symptoms are a clicking noise when turning the key or complete engine silence. RAC patrols can test your starter motor and help arrange a replacement if necessary.

Fuel – diesel contamination (3%)

Putting petrol in a diesel car (or vice versa) can cause serious engine damage. Symptoms include difficulty starting, misfiring, or a smoky exhaust. RAC patrols can drain and flush the contaminated fuel from your system and provide clean fuel to get you moving again.

ECU – engine management (2%)

The Engine Control Unit (ECU) manages your car’s engine performance. Faults can be caused by electrical issues or software problems. Symptoms include warning lights on the dashboard, poor performance, or reduced fuel efficiency. RAC patrols can run diagnostic tests to identify ECU issues and reset the system if needed.

Road traffic accident (2%)

Accidents can happen due to various reasons, including driver error, poor road conditions, or mechanical failures. Symptoms of post-accident issues include visible damage, unusual noises, or warning lights. RAC patrols provide immediate support, including vehicle recovery and onward travel arrangements to get you safely to your destination or a garage.

Gearbox – manual (2%)

Manual gearbox issues can result from worn gears, clutch problems, or low transmission fluid. Symptoms include difficulty shifting gears, grinding noises, or slipping out of gear. RAC patrols can diagnose gearbox issues and perform temporary repairs at the roadside to help you reach a garage.