MOT Risk Index.co.uk

Mercedes-Benz 300 MOT pass rate and common problems

80.9% of Mercedes-Benz 300s passed the 2024 MOT (based on 2,791 first tests): 76.7% at the first attempt and 4.2% after a fix at the test centre (PRS). About 1 in 4 failed the first attempt. For its age, it fails 33% less often than normal: MOT Risk Index 66.7 (95% CI 62.4–71.3; 100 = normal).

Mercedes-Benz 300 at a glance, 2024 MOT
MeasureValueUnitCompared withYearsTests
MOT pass rate80.9%incl. 4.2% fixed at the test centre20242791
Passed at the first attempt76.7%all first tests20242791
MOT Risk Index (95% CI 62.4–71.3)66.7index100 = normal for its age · rank 169 of 761 (1 = fails least for its age)20242791
Biggest excess: Steering6.4per 1007.6 same-age2019–202418189
Dangerous defects7.4per 10011.2 UK, not age-adjusted2019–202418189
Advisory items140.7per 100127.1 UK, not age-adjusted2019–202418189
strip · Mercedes-Benz 300 · MOT Risk Index · 66.7 vs 100 = normal · 2024
MOT Risk Index · Mercedes-Benz 300. 0–240; 100 = normal for its age; median model 92.8 · rank 169 of 761 (1 = fails least for its age). It would rank between 149 and 187 anywhere within its 95% interval, other models held where they are. DVSA, 2024.
Mercedes-Benz 300 index position among 761 models
MeasureValueUnitCompared withYearsTests
Rank169of 761published models, 1 = fails least for its age20242791
Best rank within its 95% interval149rankother models held where they are20242791
Worst rank within its 95% interval187rankother models held where they are20242791

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Download this page's numbers (CSV) · How to cite

Data release dvsa-2024-v2 (24 Sep 2026) · full dataset (v5). This model's index changed from 61.9 to 66.7 in the 24 September 2026 release, after duplicate test records were removed.

What actually fails on a Mercedes-Benz 300 MOT, and how often?

Mercedes-Benz 300 MOTs fail most often on ‘lamps, reflectors and electrical equipment’: 20.8 per 100 tests, against 29.4 for UK cars of the same age (2019–2024, n = 18,189).

bar · Mercedes-Benz 300 · Lamps, reflectors and electrical equipment · 20.8 vs 29.4 · 2019–2024
DVSA MOT bulk data, 24 Sep 2026.
Mercedes-Benz 300: the numbers behind this answer (2019–2024)
MeasureValueUnitCompared withYearsTests
Lamps, reflectors and electrical equipment20.8per 10029.42019–20243781
Suspension18per 10019.32019–20243276
Brakes13.3per 10020.22019–20242414
Body, chassis, structure8.8per 10015.02019–20241597
Visibility7.9per 10010.62019–20241440
Steering6.4per 1007.62019–20241163

Source: DVSA MOT bulk data · Window: 2019–2024 · n = 18,189 (initial tests) · Method: one initial test per test_id · Updated: 24 Sep 2026 · Release: dvsa-2024-v2 · CSV

Will my Mercedes-Benz 300's advisory become a fail at the next MOT?

Mercedes-Benz 300 advisories turn into fails less often than on the median model; the one to watch is suspension: advisories on it became a fail at the next MOT 16.5% of the time.

funnel · Mercedes-Benz 300 · Suspension · 16.5 vs median model · 2019–2024
Advisories on suspension: 16.5 of 100 became a fail on the same item at the next MOT. DVSA MOT bulk data, 24 Sep 2026.
Mercedes-Benz 300: the numbers behind this answer (2019–2024)
MeasureValueUnitCompared withYearsTests
Suspension16.5% next failmedian model2019–20242348
Brakes11.9% next failmedian model2019–20242517
Steering10.2% next failmedian model2019–2024791
Body, chassis, structure9.8% next failmedian model2019–20241210
Tyres6.8% next failmedian model2019–20241550
Noise, emissions and leaks5.0% next failmedian model2019–20241888
Non-component advisories0% next failmedian model2019–2024552

Source: DVSA MOT bulk data · Window: 2019–2024 · n = 2,791 (initial tests) · Method: one initial test per test_id · Updated: 24 Sep 2026 · Release: dvsa-2024-v2 · CSV

My Mercedes-Benz 300 got an MOT advisory: what gets flagged most?

Mercedes-Benz 300 MOTs flag suspension most: 38.1 advisories per 100 tests, against 26.2 across UK tests (2019–2024, n = 18,189).

bar · Mercedes-Benz 300 · Suspension · 38.1 vs 26.2 · 2019–2024
DVSA MOT bulk data, 24 Sep 2026.
Mercedes-Benz 300: the numbers behind this answer (2019–2024)
MeasureValueUnitCompared withYearsTests
Suspension38.1per 10026.22019–20246925
Brakes37.3per 10034.72019–20246790
Tyres20.4per 10039.72019–20243708
Noise, emissions and leaks16.9per 1005.22019–20243082
Body, chassis, structure12.4per 1004.62019–20242256
Steering6.8per 1001.82019–20241240

Source: DVSA MOT bulk data · Window: 2019–2024 · n = 18,189 (initial tests) · Method: one initial test per test_id · Updated: 24 Sep 2026 · Release: dvsa-2024-v2 · CSV

What is likely to fail next on a Mercedes-Benz 300?

For Mercedes-Benz 300s aged 20 or older whose last MOT was a pass, the item most likely to fail at the next MOT is suspension: 7.0% failed on it (2019–2024, n = 6,341).

bar · Mercedes-Benz 300 · Suspension, 20 years or older, after a pass · 7.0 vs baseline · 2019–2024
DVSA MOT bulk data, 24 Sep 2026.
Mercedes-Benz 300: the numbers behind this answer (2019–2024)
MeasureValueUnitCompared withYearsTests
Suspension, 20 years or older, after a pass7.0% next fail2019–20246341
Lamps, reflectors and electrical equipment, 20 years or older, after a pass6.1% next fail2019–20246341
Brakes, 20 years or older, after a pass3.7% next fail2019–20246341
Visibility, 20 years or older, after a pass3.7% next fail2019–20246341
Body, chassis, structure, 20 years or older, after a pass3.1% next fail2019–20246341
Steering, 20 years or older, after a pass2.7% next fail2019–20246341
Noise, emissions and leaks, 20 years or older, after a pass2.1% next fail2019–20246341
Tyres, 20 years or older, after a pass1.1% next fail2019–20246341
Full table
Further values · 2019–2024
MeasureValueUnitCompared withYearsTests
Seat belts and supplementary restraint systems, 20 years or older, after a pass0.4% next fail2019–20246341
Identification of the vehicle, 20 years or older, after a pass0.2% next fail2019–20246341
Road wheels, 20 years or older, after a pass0.1% next fail2019–20246341
Speedometer and speed limiter, 20 years or older, after a pass0.1% next fail2019–20246341
Suspension, 20 years or older, after an advisory13.5% next fail2019–20243437
Lamps, reflectors and electrical equipment, 20 years or older, after an advisory12.0% next fail2019–20243437
Brakes, 20 years or older, after an advisory8.2% next fail2019–20243437
Visibility, 20 years or older, after an advisory7.8% next fail2019–20243437
Body, chassis, structure, 20 years or older, after an advisory6.1% next fail2019–20243437
Steering, 20 years or older, after an advisory5.3% next fail2019–20243437
Noise, emissions and leaks, 20 years or older, after an advisory3.6% next fail2019–20243437
Tyres, 20 years or older, after an advisory3.0% next fail2019–20243437
Seat belts and supplementary restraint systems, 20 years or older, after an advisory1.0% next fail2019–20243437
Identification of the vehicle, 20 years or older, after an advisory0.3% next fail2019–20243437
Road wheels, 20 years or older, after an advisory0.1% next fail2019–20243437
Lamps, reflectors and electrical equipment, 20 years or older, after a fail17.2% next fail2019–20243252
Suspension, 20 years or older, after a fail15.3% next fail2019–20243252
Brakes, 20 years or older, after a fail10.3% next fail2019–20243252
Visibility, 20 years or older, after a fail9.3% next fail2019–20243252
Body, chassis, structure, 20 years or older, after a fail8.4% next fail2019–20243252
Steering, 20 years or older, after a fail6.3% next fail2019–20243252
Noise, emissions and leaks, 20 years or older, after a fail4.9% next fail2019–20243252
Tyres, 20 years or older, after a fail2.9% next fail2019–20243252
Seat belts and supplementary restraint systems, 20 years or older, after a fail2.1% next fail2019–20243252
Identification of the vehicle, 20 years or older, after a fail0.6% next fail2019–20243252
Road wheels, 20 years or older, after a fail0.2% next fail2019–20243252
Suspension, an unknown age, after a fail (rough estimate: 100 cars)17% next fail2019–2024100
Lamps, reflectors and electrical equipment, an unknown age, after a fail (rough estimate: 100 cars)13% next fail2019–2024100
Visibility, an unknown age, after a fail (rough estimate: 100 cars)9% next fail2019–2024100
Steering, an unknown age, after a fail (rough estimate: 100 cars)5% next fail2019–2024100

Source: DVSA MOT bulk data · Window: 2019–2024 · n = 2,791 (initial tests) · Method: one initial test per test_id · Updated: 24 Sep 2026 · Release: dvsa-2024-v2 · CSV

How often does a Mercedes-Benz 300 get a dangerous MOT defect?

The Mercedes-Benz 300 gets a dangerous defect less often than the UK average: 7.4 per 100 first tests against 11.2 across the UK. In the same tests, 60.7 major and 17.3 minor defects were recorded per 100 tests (one test can record several).

bullet · Mercedes-Benz 300 · Dangerous defects · 7.4 vs 11.2 · 2019–2024
Dangerous defects: 7.4 vs 11.2. DVSA MOT bulk data, 24 Sep 2026.
Mercedes-Benz 300: the numbers behind this answer (2019–2024)
MeasureValueUnitCompared withYearsTests
Dangerous defects7.4per 10011.22019–202418189

Source: DVSA MOT bulk data · Window: 2019–2024 · n = 18,189 (initial tests) · Method: one initial test per test_id; severity not recorded for some 2018–2021 tests · Updated: 24 Sep 2026 · Release: dvsa-2024-v2 · CSV

How much does it cost to fix a Mercedes-Benz 300 MOT fail?

Expected repair cost per Mercedes-Benz 300 MOT: about £81 (up to about £155 if more expensive parts are needed), from the chance of failing each item and its most common UK repair price (catalogue estimate, n = 2,791).

Computed, not measured.

bar · Mercedes-Benz 300 · Expected repair bill · 81.5 vs modal price catalogue · price catalogue
DVSA MOT bulk data, 24 Sep 2026.
Mercedes-Benz 300: the numbers behind this answer (price catalogue)
MeasureValueUnitCompared withYearsTests
Expected repair bill81.5GBP estimatemodal price catalogueprice catalogue2791
Estimated range lower81.5GBP estimatemodal price catalogueprice catalogue2791
Estimated range upper154.8GBP estimatemodal price catalogueprice catalogue2791
Suspension: Suspension coil spring (single corner)32.4GBP expected contribution180price catalogue2791
Lamps, reflectors and electrical equipment: Battery replacement (standard 12V lead-acid)29.1GBP expected contribution140price catalogue2791
Brakes: Front brake pads (parts + labour, typical hatchback)19.9GBP expected contribution150price catalogue2791

Source: DVSA MOT bulk data · Window: price catalogue · n = 2,791 (initial tests) · Method: computed estimate, not measured · Updated: 24 Sep 2026 · Release: dvsa-2024-v2 · CSV

Is the Mercedes-Benz 300 more reliable than similar cars?

Of 8 similar models, 4 fail less often for their age than the Mercedes-Benz 300 and 4 as often or more. The Mercedes-Benz 300 has an MOT Risk Index of 66.7, where 100 = normal for its age (2024, n = 2,791).

bar · Mercedes-Benz 300 · Mercedes-Benz 300 (this model) · 66.7 vs 100 = normal · 2024
DVSA MOT bulk data, 24 Sep 2026.
Mercedes-Benz 300: the numbers behind this answer (2024)
MeasureValueUnitCompared withYearsTests
Mercedes-Benz 300 (this model)66.7index100 = normal20242791
Mercedes-Benz GL61.5index66.720243626
Mercedes-Benz GLS78.1index66.720242759
Mercedes-Benz CL54.8index66.720243060
Mercedes-Benz 19079index66.720242562
Mercedes-Benz SLC70.9index66.720248972
Nissan 350Z66.5index66.720245215
Honda CR-Z62.5index66.720243791
Full table
Further values · 2024
MeasureValueUnitCompared withYearsTests
Mercedes-Benz GLB75.3index66.720246885

Source: DVSA MOT bulk data · Window: 2024 · n = 2,791 (initial tests) · Method: one initial test per test_id · Updated: 24 Sep 2026 · Release: dvsa-2024-v2 · CSV

Does high mileage mean more Mercedes-Benz 300 MOT failures at the same age?

At ages 15+, 20.5% of Mercedes-Benz 300s with 40,000 to 70,000 miles failed first time, against 29.1% of those with over 140,000 miles (2024, n = 190). No clear mileage gap inside this age group, among cars still being tested.

bar · Mercedes-Benz 300 · Age 15+, 40-70k miles (rough estimate: 73 tests, 95% interval 12.9–31.2%) · 20.5 vs baseline · 2024
DVSA MOT bulk data, 24 Sep 2026.
Mercedes-Benz 300: the numbers behind this answer (2024)
MeasureValueUnitCompared withYearsTests
Age 15+, 40-70k miles (rough estimate: 73 tests, 95% interval 12.9–31.2%)20.5% failed first time202473
Age 15+, 70-100k miles (rough estimate: 96 tests, 95% interval 10.5–25.4%)16.7% failed first time202496
Age 15+, 100-140k miles (rough estimate: 91 tests, 95% interval 18.4–36.3%)26.4% failed first time202491
Age 15+, 140k+ miles (rough estimate: 117 tests, 95% interval 21.6–37.8%)29.1% failed first time2024117

Source: DVSA MOT bulk data · Window: 2024 · n = 2,791 (initial tests) · Method: one initial test per test_id · Updated: 24 Sep 2026 · Release: dvsa-2024-v2 · CSV

How many miles does a Mercedes-Benz 300 last?

54.7% of Mercedes-Benz 300s tested had reached 100,000 miles, and 23.2% had reached 150,000 (2024, n = 9,926).

line · Mercedes-Benz 300 · 100,000 miles · 54.7 vs baseline · 2024
100,000 miles: 54.7. 200,000 miles: 7.4. DVSA MOT bulk data, 24 Sep 2026.
Mercedes-Benz 300: the numbers behind this answer (2024)
MeasureValueUnitCompared withYearsTests
100,000 miles54.7% of tested cars20249926
150,000 miles23.2% of tested cars20244215
200,000 miles7.4% of tested cars20241337

Source: DVSA MOT bulk data · Window: 2024 · n = 2,791 (initial tests) · Method: one initial test per test_id · Updated: 24 Sep 2026 · Release: dvsa-2024-v2 · CSV

Is the Mercedes-Benz 300 driven more or less than average, and does that change the picture?

Matched on annual mileage as well as age, the Mercedes-Benz 300 index is 76.6, against 79.7 on age alone (2019–2024, n = 2,791).

slope · Mercedes-Benz 300 · Age and mileage adjusted index · 76.6 vs 79.7 · 2019–2024
Age and mileage adjusted index: 79.7 vs 76.6. DVSA MOT bulk data, 24 Sep 2026.
Mercedes-Benz 300: the numbers behind this answer (2019–2024)
MeasureValueUnitCompared withYearsTests
Age and mileage adjusted index76.6index79.72019–20242791

Source: DVSA MOT bulk data · Window: 2019–2024 · n = 2,791 (initial tests) · Method: one initial test per test_id · Updated: 24 Sep 2026 · Release: dvsa-2024-v2 · CSV

Which Mercedes-Benz 300 fuel fails its MOT less?

All Mercedes-Benz 300s tested were petrol: 21.9% failed first time (2024, n = 2,257).

bar · Mercedes-Benz 300 · Petrol · 21.9 vs other fuels · 2024
DVSA MOT bulk data, 24 Sep 2026.
Mercedes-Benz 300: the numbers behind this answer (2024)
MeasureValueUnitCompared withYearsTests
Petrol21.9% fail first timeother fuels20242257

Source: DVSA MOT bulk data · Window: 2024 · n = 2,791 (initial tests) · Method: one initial test per test_id · Updated: 24 Sep 2026 · Release: dvsa-2024-v2 · CSV

Which Mercedes-Benz 300 engine is best?

For its age, the best Mercedes-Benz 300 engine is the petrol over 2.0 litre at index 94.3, and the worst the diesel over 2.0 litre at 124.2, where 100 = the model's own average (2024, n = 2,791).

bar · Mercedes-Benz 300 · Petrol over 2.0 litre · 94.3 vs 100 = model average · 2024
DVSA MOT bulk data, 24 Sep 2026.
Mercedes-Benz 300: the numbers behind this answer (2024)
MeasureValueUnitCompared withYearsTests
Petrol over 2.0 litre94.3index vs model norm100 = model average202412831
Diesel over 2.0 litre (rough estimate: 2,872 tests, 95% interval 117.7–131.0)124.2index vs model norm100 = model average20242872

Source: DVSA MOT bulk data · Window: 2024 · n = 2,791 (initial tests) · Method: one initial test per test_id · Updated: 24 Sep 2026 · Release: dvsa-2024-v2 · CSV

Where in Britain does the Mercedes-Benz 300 fail its MOT most?

Mercedes-Benz 300 fails first-time MOTs most in Exeter (EX): 38.8% against 25.1% across Britain for this model, both 2019–2024 (2024, n = 209).

bar · Mercedes-Benz 300 · Exeter (EX) (rough estimate: 209 tests, 95% interval 32.4–45.5%) · 38.8 vs 23.3 · 2024
DVSA MOT bulk data, 24 Sep 2026.
Mercedes-Benz 300: the numbers behind this answer (2024)
MeasureValueUnitCompared withYearsTests
Exeter (EX) (rough estimate: 209 tests, 95% interval 32.4–45.5%)38.8% fail first time23.32024209
Brighton (BN) (rough estimate: 292 tests, 95% interval 32.0–43.0%)37.3% fail first time23.32024292
Hemel Hempstead (HP) (rough estimate: 321 tests, 95% interval 31.4–41.8%)36.5% fail first time23.32024321
Enfield (EN) (rough estimate: 236 tests, 95% interval 9.0–17.6%)12.7% fail first time23.32024236
Coventry (CV) (rough estimate: 444 tests, 95% interval 11.0–17.5%)14.0% fail first time23.32024444
Medway (ME) (rough estimate: 177 tests, 95% interval 10.7–21.3%)15.3% fail first time23.32024177
Bath (BA) (rough estimate: 110 tests, 95% interval 28.0–45.7%)36.4% fail first time23.32024110
Worcester (WR) (rough estimate: 122 tests, 95% interval 28.1–44.9%)36.1% fail first time23.32024122
Full table
Further values · 2024
MeasureValueUnitCompared withYearsTests
Plymouth (PL) (rough estimate: 131 tests, 95% interval 26.8–42.8%)34.4% fail first time23.32024131
Portsmouth (PO) (rough estimate: 271 tests, 95% interval 28.9–40.2%)34.3% fail first time23.32024271
Bristol (BS) (rough estimate: 211 tests, 95% interval 28.1–40.8%)34.1% fail first time23.32024211
London W (W) (rough estimate: 192 tests, 95% interval 27.0–40.3%)33.3% fail first time23.32024192
Swindon (SN) (rough estimate: 151 tests, 95% interval 25.5–40.3%)32.5% fail first time23.32024151
Oxford (OX) (rough estimate: 259 tests, 95% interval 26.3–37.6%)31.7% fail first time23.32024259
London SE (SE) (rough estimate: 274 tests, 95% interval 26.2–37.1%)31.4% fail first time23.32024274
Colchester (CO) (rough estimate: 176 tests, 95% interval 24.9–38.4%)31.3% fail first time23.32024176
Stoke-on-Trent (ST) (rough estimate: 120 tests, 95% interval 23.3–39.6%)30.8% fail first time23.32024120
Milton Keynes (MK) (rough estimate: 170 tests, 95% interval 24.2–37.9%)30.6% fail first time23.32024170
Southampton (SO) (rough estimate: 227 tests, 95% interval 24.4–36.2%)30.0% fail first time23.32024227
Aberdeen (AB) (rough estimate: 114 tests, 95% interval 22.2–38.8%)29.8% fail first time23.32024114
Reading (RG) (rough estimate: 322 tests, 95% interval 24.2–34.1%)28.9% fail first time23.32024322
Swansea (SA) (rough estimate: 136 tests, 95% interval 21.7–36.8%)28.7% fail first time23.32024136
Liverpool (L) (rough estimate: 113 tests, 95% interval 20.8–37.2%)28.3% fail first time23.32024113
Ipswich (IP) (rough estimate: 316 tests, 95% interval 23.5–33.4%)28.2% fail first time23.32024316
Guildford (GU) (rough estimate: 360 tests, 95% interval 23.7–32.9%)28.1% fail first time23.32024360
Gloucester (GL) (rough estimate: 255 tests, 95% interval 22.7–33.6%)27.8% fail first time23.32024255
Leeds (LS) (rough estimate: 126 tests, 95% interval 20.7–36.2%)27.8% fail first time23.32024126
Llandudno (LL) (rough estimate: 149 tests, 95% interval 21.0–35.2%)27.5% fail first time23.32024149
Bournemouth (BH) (rough estimate: 261 tests, 95% interval 22.2–32.9%)27.2% fail first time23.32024261
Tonbridge (TN) (rough estimate: 428 tests, 95% interval 23.1–31.5%)27.1% fail first time23.32024428
Wolverhampton (WV) (rough estimate: 108 tests, 95% interval 19.4–35.9%)26.9% fail first time23.32024108
Harrow (HA) (rough estimate: 160 tests, 95% interval 20.0–33.6%)26.3% fail first time23.32024160
Derby (DE) (rough estimate: 131 tests, 95% interval 19.2–34.1%)25.9% fail first time23.32024131
London SW (SW) (rough estimate: 253 tests, 95% interval 20.7–31.4%)25.7% fail first time23.32024253
Peterborough (PE) (rough estimate: 274 tests, 95% interval 20.7–31.0%)25.6% fail first time23.32024274
Bradford (BD) (rough estimate: 117 tests, 95% interval 17.9–33.3%)24.8% fail first time23.32024117
Sheffield (S) (rough estimate: 303 tests, 95% interval 20.2–29.9%)24.8% fail first time23.32024303
Canterbury (CT) (rough estimate: 175 tests, 95% interval 18.8–31.4%)24.6% fail first time23.32024175
Edinburgh (EH) (rough estimate: 114 tests, 95% interval 17.6–33.2%)24.6% fail first time23.32024114
St Albans (AL) (rough estimate: 106 tests, 95% interval 17.3–33.5%)24.5% fail first time23.32024106
Redhill (RH) (rough estimate: 282 tests, 95% interval 19.5–29.4%)24.1% fail first time23.32024282
Kingston upon Thames (KT) (rough estimate: 386 tests, 95% interval 19.9–28.3%)23.8% fail first time23.32024386
London N (N) (rough estimate: 299 tests, 95% interval 19.3–28.9%)23.8% fail first time23.32024299
Stockport (SK) (rough estimate: 190 tests, 95% interval 18.2–30.2%)23.7% fail first time23.32024190
Doncaster (DN) (rough estimate: 169 tests, 95% interval 17.9–30.6%)23.7% fail first time23.32024169
Northampton (NN) (rough estimate: 225 tests, 95% interval 18.5–29.5%)23.6% fail first time23.32024225
Newport (NP) (rough estimate: 115 tests, 95% interval 16.7–32.0%)23.5% fail first time23.32024115
Ilford (IG) (rough estimate: 153 tests, 95% interval 16.9–30.2%)22.9% fail first time23.32024153
York (YO) (rough estimate: 228 tests, 95% interval 17.8–28.7%)22.8% fail first time23.32024228
Preston (PR) (rough estimate: 141 tests, 95% interval 16.6–30.3%)22.7% fail first time23.32024141
Twickenham (TW) (rough estimate: 319 tests, 95% interval 18.3–27.5%)22.6% fail first time23.32024319
Chester (CH) (rough estimate: 103 tests, 95% interval 15.4–31.3%)22.3% fail first time23.32024103
Newcastle (NE) (rough estimate: 176 tests, 95% interval 16.7–28.9%)22.2% fail first time23.32024176
Manchester (M) (rough estimate: 172 tests, 95% interval 16.5–28.9%)22.1% fail first time23.32024172
Glasgow (G) (rough estimate: 154 tests, 95% interval 16.3–29.3%)22.1% fail first time23.32024154
Nottingham (NG) (rough estimate: 251 tests, 95% interval 17.2–27.4%)21.9% fail first time23.32024251
Norwich (NR) (rough estimate: 254 tests, 95% interval 16.7–26.7%)21.3% fail first time23.32024254
London NW (NW) (rough estimate: 295 tests, 95% interval 16.4–25.7%)20.7% fail first time23.32024295
Dartford (DA) (rough estimate: 184 tests, 95% interval 15.4–27.1%)20.6% fail first time23.32024184
Leicester (LE) (rough estimate: 254 tests, 95% interval 16.0–25.9%)20.5% fail first time23.32024254
Slough (SL) (rough estimate: 260 tests, 95% interval 15.9–25.7%)20.4% fail first time23.32024260
Stevenage (SG) (rough estimate: 182 tests, 95% interval 15.1–26.8%)20.3% fail first time23.32024182
Cardiff (CF) (rough estimate: 164 tests, 95% interval 14.7–26.9%)20.1% fail first time23.32024164
Romford (RM) (rough estimate: 210 tests, 95% interval 15.2–25.9%)20% fail first time23.32024210
Cambridge (CB) (rough estimate: 172 tests, 95% interval 14.5–26.4%)19.8% fail first time23.32024172
London E (E) (rough estimate: 196 tests, 95% interval 14.5–25.5%)19.4% fail first time23.32024196
Warrington (WA) (rough estimate: 104 tests, 95% interval 12.8–27.8%)19.2% fail first time23.32024104
Croydon (CR) (rough estimate: 199 tests, 95% interval 14.2–25.1%)19.1% fail first time23.32024199
Chelmsford (CM) (rough estimate: 347 tests, 95% interval 15.2–23.5%)19.0% fail first time23.32024347
Darlington (DL) (rough estimate: 116 tests, 95% interval 12.2–26.1%)18.1% fail first time23.32024116
Wakefield (WF) (rough estimate: 122 tests, 95% interval 12.2–25.8%)18.0% fail first time23.32024122
Shrewsbury (SY) (rough estimate: 100 tests, 95% interval 11.7–26.7%)18% fail first time23.32024100
Birmingham (B) (rough estimate: 464 tests, 95% interval 14.7–21.6%)17.9% fail first time23.32024464
Uxbridge (UB) (rough estimate: 232 tests, 95% interval 13.3–23.1%)17.7% fail first time23.32024232
Southend-on-Sea (SS) (rough estimate: 187 tests, 95% interval 12.9–23.7%)17.6% fail first time23.32024187

Source: DVSA MOT bulk data · Window: 2024 · n = 2,791 (initial tests) · Method: one initial test per test_id · Updated: 24 Sep 2026 · Release: dvsa-2024-v2 · CSV

Does a Mercedes-Benz 300 rust more than average?

Allowing for age, Mercedes-Benz 300 MOTs record corrosion failures at 5.3 times the national rate: 4.06% of tests against 0.77% (2024 + geographic layers, n = 454).

Computed, not measured.

slope · Mercedes-Benz 300 · Salt belt susceptibility · 5.3 vs 1 · 2024 + geographic layers
Salt belt susceptibility: 1 vs 5.3. DVSA MOT bulk data, 24 Sep 2026.
Mercedes-Benz 300: the numbers behind this answer (2024 + geographic layers)
MeasureValueUnitCompared withYearsTests
Salt belt susceptibility5.3ratio estimate12024 + geographic layers454

Source: DVSA MOT bulk data · Window: 2024 + geographic layers · n = 2,791 (initial tests) · Method: computed estimate, not measured · Updated: 24 Sep 2026 · Release: dvsa-2024-v2 · CSV

What do six years of MOTs show about owning a Mercedes-Benz 300?

Of failed Mercedes-Benz 300 MOTs, 21.0% were retested the same day and a further 67.8% within 10 days; the median failed car passed its retest after 3 days (2019–2024, n = 2,645).

bar · Mercedes-Benz 300 · Same-day retest · 21.0 vs failed initial tests · 2019–2024
DVSA MOT bulk data, 24 Sep 2026.
Mercedes-Benz 300: the numbers behind this answer (2019–2024)
MeasureValueUnitCompared withYearsTests
Same-day retest21.0%failed initial tests2019–20242645
Retest within 10 days67.8%failed initial tests2019–20242645
Clean MOT streak43.1%observed chains2019–20243415
Repeat advisory26.7%observed chains2019–20243415
Decreasing odometer3.4% mileage anomalyobserved chains2019–20244067

Source: DVSA MOT bulk data · Window: 2019–2024 · n = 2,791 (initial tests) · Method: one initial test per test_id · Updated: 24 Sep 2026 · Release: dvsa-2024-v2 · CSV

If a Mercedes-Benz 300 fails, does it fail again?

24.6% of Mercedes-Benz 300s that failed an MOT failed the next one too, against 18.9% after a pass (2019–2024, n = 1,283). The failure most likely to come back is tyres: 25.9% of those fails recurred at the next MOT.

bullet · Mercedes-Benz 300 · Repeat after fail · 24.6 vs 18.9 · 2019–2024
Repeat after fail: 24.6 vs 18.9. DVSA MOT bulk data, 24 Sep 2026.
Mercedes-Benz 300: the numbers behind this answer (2019–2024)
MeasureValueUnitCompared withYearsTests
Repeat after fail24.6%18.92019–20241283

Source: DVSA MOT bulk data · Window: 2019–2024 · n = 2,791 (initial tests) · Method: one initial test per test_id · Updated: 24 Sep 2026 · Release: dvsa-2024-v2 · CSV

Which Mercedes-Benz 300 faults come together?

On Mercedes-Benz 300s, ‘body, chassis, structure’ and seat belts and supplementary restraint systems failures turn up together 6.3 times as often as chance would predict (2024, n = 73).

Mercedes-Benz 300: the numbers behind this answer (2024)
MeasureValueUnitCompared withYearsTests
Body, chassis, structure + Seat belts and supplementary restraint systems (rough estimate: 73 tests, 95% interval 5.0–8.0)6.3liftexpected joint rate202473
Identification of the vehicle + Lamps, reflectors and electrical equipment (rough estimate: 46 tests, 95% interval 4.3–7.7)5.8liftexpected joint rate202446
Seat belts and supplementary restraint systems + Suspension (rough estimate: 127 tests, 95% interval 4.8–6.9)5.8liftexpected joint rate2024127
Brakes + Seat belts and supplementary restraint systems (rough estimate: 84 tests, 95% interval 4.5–7.0)5.6liftexpected joint rate202484
Lamps, reflectors and electrical equipment + Seat belts and supplementary restraint systems (rough estimate: 121 tests, 95% interval 4.4–6.4)5.3liftexpected joint rate2024121
Identification of the vehicle + Visibility (rough estimate: 24 tests, 95% interval 3.3–7.8)5.2liftexpected joint rate202424
Body, chassis, structure + Noise, emissions and leaks (rough estimate: 180 tests, 95% interval 4.4–5.9)5.1liftexpected joint rate2024180
Seat belts and supplementary restraint systems + Steering (rough estimate: 45 tests, 95% interval 3.5–6.5)4.9liftexpected joint rate202445
Full table
Further values · 2024
MeasureValueUnitCompared withYearsTests
Brakes + Identification of the vehicle (rough estimate: 25 tests, 95% interval 3.1–7.1)4.8liftexpected joint rate202425
Body, chassis, structure + Brakes (rough estimate: 364 tests, 95% interval 4.2–5.2)4.7liftexpected joint rate2024364
Brakes + Noise, emissions and leaks (rough estimate: 210 tests, 95% interval 4.0–5.3)4.6liftexpected joint rate2024210
Noise, emissions and leaks + Seat belts and supplementary restraint systems (rough estimate: 31 tests, 95% interval 3.1–6.5)4.6liftexpected joint rate202431
Lamps, reflectors and electrical equipment + Noise, emissions and leaks (rough estimate: 304 tests, 95% interval 3.9–4.9)4.4liftexpected joint rate2024304
Body, chassis, structure + Lamps, reflectors and electrical equipment4.3liftexpected joint rate2024504
Brakes + Tyres (rough estimate: 137 tests, 95% interval 3.5–4.9)4.2liftexpected joint rate2024137
Identification of the vehicle + Suspension (rough estimate: 31 tests, 95% interval 2.8–5.8)4.0liftexpected joint rate202431
Body, chassis, structure + Tyres (rough estimate: 101 tests, 95% interval 3.2–4.8)4.0liftexpected joint rate2024101
Lamps, reflectors and electrical equipment + Tyres (rough estimate: 198 tests, 95% interval 3.4–4.5)4.0liftexpected joint rate2024198
Brakes + Lamps, reflectors and electrical equipment3.9liftexpected joint rate2024600
Steering + Tyres (rough estimate: 77 tests, 95% interval 3.0–4.7)3.8liftexpected joint rate202477
Lamps, reflectors and electrical equipment + Visibility3.7liftexpected joint rate2024505
Body, chassis, structure + Visibility (rough estimate: 252 tests, 95% interval 3.2–4.2)3.7liftexpected joint rate2024252
Noise, emissions and leaks + Tyres (rough estimate: 55 tests, 95% interval 2.8–4.8)3.7liftexpected joint rate202455
Seat belts and supplementary restraint systems + Visibility (rough estimate: 47 tests, 95% interval 2.6–4.7)3.6liftexpected joint rate202447
Body, chassis, structure + Suspension (rough estimate: 402 tests, 95% interval 3.2–3.9)3.5liftexpected joint rate2024402
Brakes + Visibility (rough estimate: 305 tests, 95% interval 3.1–3.8)3.4liftexpected joint rate2024305
Brakes + Steering (rough estimate: 212 tests, 95% interval 3.0–3.9)3.4liftexpected joint rate2024212
Brakes + Suspension3.4liftexpected joint rate2024502
Body, chassis, structure + Steering (rough estimate: 163 tests, 95% interval 2.9–4.0)3.4liftexpected joint rate2024163
Tyres + Visibility (rough estimate: 96 tests, 95% interval 2.7–4.0)3.3liftexpected joint rate202496
Noise, emissions and leaks + Steering (rough estimate: 93 tests, 95% interval 2.7–4.0)3.3liftexpected joint rate202493
Steering + Suspension (rough estimate: 288 tests, 95% interval 2.8–3.5)3.1liftexpected joint rate2024288
Lamps, reflectors and electrical equipment + Suspension3.0liftexpected joint rate2024687
Lamps, reflectors and electrical equipment + Steering (rough estimate: 289 tests, 95% interval 2.7–3.4)3.0liftexpected joint rate2024289
Noise, emissions and leaks + Suspension (rough estimate: 197 tests, 95% interval 2.5–3.4)2.9liftexpected joint rate2024197
Suspension + Tyres (rough estimate: 138 tests, 95% interval 2.4–3.4)2.9liftexpected joint rate2024138
Noise, emissions and leaks + Visibility (rough estimate: 115 tests, 95% interval 2.4–3.4)2.9liftexpected joint rate2024115
Suspension + Visibility (rough estimate: 353 tests, 95% interval 2.4–3.0)2.7liftexpected joint rate2024353
Steering + Visibility (rough estimate: 140 tests, 95% interval 2.1–3.0)2.5liftexpected joint rate2024140
Body, chassis, structure + Identification of the vehicle (seen together; too few for a multiplier)19tests with both202419
Seat belts and supplementary restraint systems + Tyres (seen together; too few for a multiplier)19tests with both202419
Lamps, reflectors and electrical equipment + Road Wheels (seen together; too few for a multiplier)17tests with both202417
Brakes + Road Wheels (seen together; too few for a multiplier)16tests with both202416
Identification of the vehicle + Steering (seen together; too few for a multiplier)16tests with both202416
Body, chassis, structure + Road Wheels (seen together; too few for a multiplier)13tests with both202413
Road Wheels + Visibility (seen together; too few for a multiplier)12tests with both202412
Lamps, reflectors and electrical equipment + Speedometer and speed limiter (seen together; too few for a multiplier)11tests with both202411
Identification of the vehicle + Noise, emissions and leaks (seen together; too few for a multiplier)11tests with both202411
Road Wheels + Suspension (seen together; too few for a multiplier)11tests with both202411
Identification of the vehicle + Tyres (seen together; too few for a multiplier)10tests with both202410
Road Wheels + Tyres (seen together; too few for a multiplier)8tests with both20248
Speedometer and speed limiter + Suspension (seen together; too few for a multiplier)8tests with both20248
Road Wheels + Steering (seen together; too few for a multiplier)8tests with both20248
Identification of the vehicle + Seat belts and supplementary restraint systems (seen together; too few for a multiplier)6tests with both20246
Speedometer and speed limiter + Visibility (seen together; too few for a multiplier)6tests with both20246
Brakes + Speedometer and speed limiter (seen together; too few for a multiplier)5tests with both20245
Noise, emissions and leaks + Road Wheels (seen together; too few for a multiplier)5tests with both20245

Source: DVSA MOT bulk data · Window: 2024 · n = 2,791 (initial tests) · Method: one initial test per test_id · Updated: 24 Sep 2026 · Release: dvsa-2024-v2 · CSV

Does the Mercedes-Benz 300 fail inspections in other countries too?

In the Netherlands, 60.1% of Mercedes-Benz 300s failed their periodic roadworthiness inspection, against 50.8% for all cars there (2024 by country, n = 1,088 inspections).

Both readings are shown: this comparison changes when usage or inspection rules differ.

Inspections abroad disagree: none point the same way as Britain, Norway and the Netherlands do not. Test rules, climate and how the vehicles are used differ, so both readings are shown.

bullet · Mercedes-Benz 300 · Norway · 49.2 vs 33.7 · 2024 by country
Norway: 49.2 vs 33.7. Netherlands: 60.1 vs 50.8. Statens vegvesen PKK (CC BY 4.0), Traficom Katsastus (CC BY 4.0), RDW APK (CC0), adapted; covers 430 of 761 models, 24 Sep 2026.
Mercedes-Benz 300: the numbers behind this answer (2024 by country)
MeasureValueUnitCompared withYearsTests
Norway49.2% failed33.72024 by country565
Netherlands60.1% failed50.82024 by country1088

Source: Statens vegvesen PKK (CC BY 4.0), Traficom Katsastus (CC BY 4.0), RDW APK (CC0), adapted; covers 430 of 761 models · Window: 2024 by country · n = 2,791 (initial tests) · Method: one initial test per test_id · Updated: 24 Sep 2026 · Release: dvsa-2024-v2 · CSV · licences and full notice

Does the month of a Mercedes-Benz 300 MOT matter?

Mercedes-Benz 300s fail first time most in January (29.9%, against 31.1% for all cars that month) and least in July (23.1%) (2024, n = 2,791).

line · Mercedes-Benz 300 · January · 29.9 vs 31.1 · 2024
January: 29.9. December: 26.2. DVSA MOT bulk data, 24 Sep 2026.
Mercedes-Benz 300: the numbers behind this answer (2024)
MeasureValueUnitCompared withYearsTests
January29.9% fail first time31.120241160
February26.7% fail first time30.020241083
March26.6% fail first time28.320241562
April23.8% fail first time29.820241503
May24.2% fail first time28.820241681
June25.3% fail first time28.120241814
July23.1% fail first time29.320242000
August23.6% fail first time29.220241759
Full table
Further values · 2024
MeasureValueUnitCompared withYearsTests
September25.3% fail first time28.220241632
October24.5% fail first time30.320241664
November25.1% fail first time30.620241318
December26.2% fail first time29.320241013

Source: DVSA MOT bulk data · Window: 2024 · n = 2,791 (initial tests) · Method: one initial test per test_id · Updated: 24 Sep 2026 · Release: dvsa-2024-v2 · CSV

Not enough tests for… (and why)

Tyres, brakes and suspension: how does the Mercedes-Benz 300 compare with cars of the same age?

not computed for this model: no qualifying records. 2,791 initial Mercedes-Benz 300 tests are in the published model cohort.

Source: DVSA MOT bulk data · Window: 2019–2024 · n = 2,791 (initial tests) · Method: one initial test per test_id · Updated: 24 Sep 2026 · Release: dvsa-2024-v2 · CSV

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What have dealers been told about the Mercedes-Benz 300? (US market)

layer not yet computed for this model (covers 211 of 761 models). 2,791 initial Mercedes-Benz 300 tests are in the published model cohort.

Source: NHTSA, US market; covers 211 of 761 models · Window: NHTSA · n = 2,791 (initial tests) · Method: one initial test per test_id · Updated: 24 Sep 2026 · Release: dvsa-2024-v2 · CSV

See the Mercedes-Benz SLC, a car of the same inspection class with 3.2× the tests · Check your car by registration

Real-world MPG against the official figure (manufacturer level)

layer not yet computed for this model (covers 19 of 761 models). 2,791 initial Mercedes-Benz 300 tests are in the published model cohort.

Source: European Commission OBFCM; covers 19 of 761 models · Window: 2021+ cohorts · n = 2,791 (initial tests) · Method: computed estimate, not measured · Updated: 24 Sep 2026 · Release: dvsa-2024-v2 · CSV

See the Mercedes-Benz SLC, a car of the same inspection class with 3.2× the tests · Check your car by registration

How to cite this page

MOT Risk Index (2026). Mercedes-Benz 300 MOT statistics 2024 (data release dvsa-2024-v2; full dataset motriskindex-families-2024-v5, DOI 10.5281/zenodo.22975051), updated 24 September 2026. motriskindex.co.uk/cars/mercedes-300/

How the MOT Risk Index and every figure on this page are calculated: methodology.

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Mercedes-Benz 300 MOT: quick answers

What is the Mercedes-Benz 300 first-time MOT pass rate?

76.7% of first attempts passed in 2024 (2,791 tests). Retests after repair are excluded; cars fixed at the test centre (PRS) are shown separately.

Why does this number differ from other sites?

Other sites may count retests or all attempts. This page uses 2,791 primary tests: 23.32% failed first time and 80.9% passed when cars fixed at the test centre (PRS) count as passes. The age-adjusted MOT Risk Index 66.7 is shown separately.