Mercedes Benz Sl 400 Grand Edition Premium A (2020)

113 real MOT outcomes analysed • 93.7% first-time pass rate

2020 Mercedes Benz Sl 400 Grand Edition Premium A

CarHunch analysed 113 real MOT records for the 2020 Mercedes Benz Sl 400 Grand Edition Premium A. This breakdown of actual test outcomes — pass rates, defect profiles, mileage data — isn't published anywhere else.

This 2020 Mercedes-Benz SL 400 is a strong MOT performer, with a 93.7% first-time pass rate that significantly outpaces the UK average of 80%, suggesting well-maintained examples in the used market. The dangerous defect rate of 14.2% is within acceptable range, so safety issues aren't a major concern for the cohort.

The median mileage of just 15,257 miles indicates these are lightly-used vehicles for their age, which explains the low failure rate of 0.23 per car—these aren't hard-worked examples. However, the 0.8 advisories per vehicle suggest minor wear items are emerging, so budget for routine maintenance and have a pre-purchase inspection focus on suspension and trim components typical of grand tourers at this mileage point.

Generally reliable 13.7% above UK average
93.7%
pass MOT first time
UK average: ~80%
15,257
typical mileage
10,398–21,337 middle half
14.2%
ever had a dangerous defect
recorded at any MOT
0.23
avg MOT failures per car
over 3.3 tests on record

What to check before buying a 2020 Mercedes Benz Sl 400 Grand Edition Premium A

Practical pre-purchase checks for this age and model.

  • 📋 Check the full MOT history. Look for recurring advisories — slow-building issues like corrosion or brake wear patterns show up years before they become failures. Enter the reg below for a full AI analysis.
  • 🔍 Inspect for corrosion in person. Brake pipes, sills, subframes, and chassis legs. Surface rust is normal at this age; structural rust is a serious problem that's expensive to fix and can fail an MOT.
  • 🛞 Check tyres and brakes. The most common advisory items at this age. Budget for replacement if they're near the limit — factor this into your offer price.
  • 📄 Run an HPI check. The MOT history won't show outstanding finance, insurance write-offs, or stolen status — an HPI check will.

Before you buy a Mercedes Benz Sl 400 Grand Edition Premium A

MOT history is one piece of the puzzle. These checks can reveal what CarHunch can't.

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Mileage Distribution

Most 2020 Mercedes Benz Sl 400 Grand Edition Premium A vehicles sit in the blue band. If the car you're looking at is outside it, it's either unusually low or high mileage for its age.

10,398
low mileage
15,257
typical
21,337
high mileage

Half of all 2020 Mercedes Benz Sl 400 Grand Edition Premium A vehicles fall between 10,398 and 21,337 miles.

2020 Mercedes Benz Sl 400 Grand Edition Premium A — Still on the Road

Strong survival — 111 vehicles still getting MOTs in 2025, 100% of the peak.

108 111 2023 2025

Based on vehicles from this manufacture year that had at least one MOT test in each calendar year. Data from 2023–2025.

MOT History Averages

3.3
Avg MOT tests per vehicle
0.23
Avg failures per vehicle
0.8
Avg advisories per vehicle

Found a specific Mercedes Benz Sl 400 Grand Edition Premium A?

Enter the reg to see its individual MOT history, AI Hunches, and how it compares to this cohort.

UK