Mercedes Benz S 350 L Grand Ed Executive D A (2020)

333 real MOT outcomes analysed • 86.1% first-time pass rate

2020 Mercedes Benz S 350 L Grand Ed Executive D A

CarHunch analysed 333 real MOT records for the 2020 Mercedes Benz S 350 L Grand Ed Executive D A. This breakdown of actual test outcomes — pass rates, defect profiles, mileage data — isn't published anywhere else.

The 2020 Mercedes-Benz S 350 L beats the UK average with an 86.1% first-time pass rate, suggesting this diesel executive sedan is holding up well in its fifth year. However, 17.7% of these vehicles have recorded a dangerous defect at some point, which is worth noting if you're buying used—request the full MOT history and have any historical faults independently inspected.

At just under 50,000 miles on average, these cars are running low mileage for their age, which generally favours reliability. The typical vehicle racks up 0.34 failures and 2.2 advisories per test, indicating minor wear rather than systemic problems—but before purchase, have a pre-buy inspection focus on the diesel particulate filter and suspension components, which are common cost areas on high-mileage luxury diesels.

Average reliability 6.1% above UK average
86.1%
pass MOT first time
UK average: ~80%
47,574
typical mileage
31,356–63,177 middle half
17.7%
ever had a dangerous defect
recorded at any MOT
0.34
avg MOT failures per car
over 4.1 tests on record

What to check before buying a 2020 Mercedes Benz S 350 L Grand Ed Executive D 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 S 350 L Grand Ed Executive D 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 S 350 L Grand Ed Executive D 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.

31,356
low mileage
47,574
typical
63,177
high mileage

Half of all 2020 Mercedes Benz S 350 L Grand Ed Executive D A vehicles fall between 31,356 and 63,177 miles.

2020 Mercedes Benz S 350 L Grand Ed Executive D A — Still on the Road

Strong survival — 289 vehicles still getting MOTs in 2025, 98% of the peak.

15 289 2021 2025

Based on vehicles from this manufacture year that had at least one MOT test in each calendar year. Data from 2021–2025.

MOT History Averages

4.1
Avg MOT tests per vehicle
0.34
Avg failures per vehicle
2.2
Avg advisories per vehicle

Found a specific Mercedes Benz S 350 L Grand Ed Executive D A?

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

UK