The most reliable cars of 2003

Every 2003 car tested in Britain in one year, ranked by how often it failed. Measured, not surveyed.

Best

#	Car	Engine	Failure rate	Tests
1	Mercedes-Benz SL-Class	5.4 Petrol	13%	676
2	BMW M3	3.2 Petrol	13%	2,220
3	Mercedes-Benz SL-Class	5.0 Petrol	14%	1,123
4	Porsche 911	3.6 Petrol	14%	2,826
5	Mercedes-Benz SL-Class	3.7 Petrol	16%	901
6	Honda S2000	2.0 Petrol	18%	769
7	Volkswagen Golf	3.2 Petrol	18%	1,099
8	Porsche Boxster	3.2 Petrol	19%	1,567
9	Porsche Cayenne	4.5 Petrol	19%	669
10	Jaguar XKR	4.2 Petrol	20%	522
11	BMW 3 Series	3.0 Petrol	20%	3,624
12	Subaru Impreza	2.0 Petrol	21%	2,159
13	Porsche Boxster	2.7 Petrol	21%	1,409
14	Jaguar XK8	4.2 Petrol	21%	704
15	Jaguar XJ	3.0 Petrol	21%	1,110
16	Peugeot Boxer	2.0 Diesel	21%	1,601
17	Seat Leon	1.8 Petrol	22%	881
18	BMW 5 Series	3.0 Petrol	22%	700
19	Toyota RAV-4	1.8 Petrol	22%	564
20	Lexus RX300	3.0 Petrol	22%	773
21	MG TF	1.8 Petrol	22%	2,962
22	Jaguar XJ	4.2 Petrol	22%	588
23	Mercedes-Benz SLK-Class	2.3 Petrol	22%	1,064
24	Lexus IS200	2.0 Petrol	22%	1,549
25	Mercedes-Benz SLK-Class	2.0 Petrol	22%	818

Worst

#	Car	Engine	Failure rate	Tests
1	Mercedes-Benz Vito	2.2 Diesel	37%	743
2	Nissan Primastar	1.9 Diesel	35%	765
3	Vauxhall Combo	1.7 Diesel	35%	2,669
4	Ford Mondeo	2.0 Diesel	34%	1,202
5	Vauxhall Vivaro	1.9 Diesel	34%	3,344
6	Volkswagen Beetle	1.6 Petrol	34%	1,656
7	Volvo V40	1.9 Diesel	34%	513
8	Volkswagen Polo	1.4 Diesel	33%	1,257
9	Fiat Doblo	1.9 Diesel	33%	766
10	Renault Trafic	1.9 Diesel	33%	2,256
11	Citroen C3	1.4 Diesel	33%	889
12	Ford Transit Connect	1.8 Diesel	33%	4,350
13	Peugeot 307	2.0 Diesel	33%	1,456
14	Renault Kangoo	1.5 Diesel	33%	1,278
15	Ford Focus	1.8 Diesel	33%	1,597
16	Citroen Xsara	1.6 Petrol	33%	1,085
17	Volkswagen Beetle	1.9 Diesel	33%	645
18	Volkswagen Polo	1.9 Diesel	33%	1,148
19	Ford Transit	2.0 Diesel	33%	1,960
20	Vauxhall Vectra	1.8 Petrol	33%	631
21	Ford Galaxy	1.9 Diesel	33%	1,117
22	Peugeot 206	2.0 Diesel	33%	755
23	Volvo V40	1.8 Petrol	33%	584
24	Renault Clio	1.1 Petrol	33%	5,774
25	Fiat Punto	1.2 Petrol	32%	2,195

What this measures

Britain tests every car over three years old against a published standard and publishes the result. This is that record for the 2003 model year, so every car here is the same age and none is flattered by being newer.

A car driven less fails less. An expensive one often sits high for reasons that are not about how well it was built, which is why the app can rank these at the same odometer reading.