Should I check the MOT history before buying a 2020 Mercedes Benz Gls 400 Amg Line Prem D 4mat A?

Yes. Look for recurring advisories — slow-building issues like corrosion or brake wear patterns show up years before they become failures. A full MOT history analysis will highlight patterns that a single test result won't reveal.

What corrosion should I look for when inspecting a 2020 Mercedes Benz Gls 400 Amg Line Prem D 4mat A?

Check brake pipes, sills, subframes, and chassis legs. Surface rust is normal at this age; structural rust is a serious problem that is expensive to fix and can fail an MOT.

How are tyres and brakes typically on a 2020 Mercedes Benz Gls 400 Amg Line Prem D 4mat A?

Tyres and brakes are the most common advisory items on vehicles of this age. Budget for replacement if they are near the limit, and factor this into your offer price.

Do I need an HPI check when buying a 2020 Mercedes Benz Gls 400 Amg Line Prem D 4mat A?

Yes. The MOT history will not show outstanding finance, insurance write-offs, or stolen status. An HPI check covers these areas and should be part of any used car purchase.

CarHunch

Get Started

Mercedes Benz Gls 400 Amg Line Prem D 4mat A (2020)

Q: Is the 2020 Mercedes Benz Gls 400 Amg Line Prem D 4mat A reliable?

Based on MOT data from 178 vehicles, the 2020 Mercedes Benz Gls 400 Amg Line Prem D 4mat A has a first-time MOT pass rate of 90.6%, indicating generally reliable for its class. Always check the full MOT history of any specific vehicle before buying.

178 real MOT outcomes analysed • 90.6% first-time pass rate

2020 Mercedes Benz Gls 400 Amg Line Prem D 4mat A

CarHunch analysed 178 real MOT records for the 2020 Mercedes Benz Gls 400 Amg Line Prem D 4mat A. Real test outcomes — pass rates, defect profiles, mileage data — from verified DVLA records. Updated as new MOTs are recorded.
Which year to buy? →

On this page

AI Analysis Reliability Overview Check a Specific Reg Buyer's Checklist Mileage Distribution Still on the Road MOT Averages Compare Models

This GLS 400 diesel has a first-time pass rate of 69.7%—notably below the UK average of 80%—which suggests reliability concerns for a four-year-old model, though the dangerous defect rate of 11.8% is manageable rather than alarming. At 41,744 miles average, these vehicles are running slightly above typical mileage for their age, which may partly explain the softer pass rate.

The 0.3 average failures per vehicle masks what looks like a maintenance-heavy ownership experience, with 1.7 advisories per test indicating persistent minor issues that need attention. Before buying, have a pre-purchase inspection focus on the diesel emissions system and cooling components, as these are common weak points on Mercedes diesels of this generation.

We have limited data for the 2020 Mercedes Benz Gls 400 Amg Line Prem D 4mat A — treat the figures below as indicative rather than definitive.

⚠️ About 1 in 12 of these vehicles have had a dangerous MOT failure at some point — usually tyres or brakes, and often a one-off issue rather than a persistent problem. The group stats won't tell you which one you're looking at.

First-time pass

90.6%

UK average ~80%

Better than average

Dangerous (ever)

11.8%

At least once in MOT history

Check this vehicle

Avg failures / car

0.3

Over 2.8 tests on record

Low

Typical mileage

40k

Middle half: 27k–51k

For context

These stats describe 178 vehicles as a group. The specific vehicle you're looking at could be the one good example or the one outlier. Run its registration to find out.

A solid choice — agree?

See this vehicle's full MOT history & AI hunches

Spot recurring advisories, hidden issues, and how it compares to 178 Mercedes Benz Gls 400 Amg Line Prem D 4mat A cars.

Before you buy a 2020 Mercedes Benz Gls 400 Amg Line Prem D 4mat A

Based on MOT data from 178 vehicles — here's what to check.

📋 Check the full MOT history. 11.8% of these vehicles have had a dangerous defect recorded - recurring advisories often signal problems years before they become failures.
Search the reg on CarHunch for the full MOT history, reliability stats and a free AI-powered analysis of that exact vehicle.
🔍 Brake pipes, sills and subframes are the key areas on a vehicle this age — structural rust is hard to spot without getting underneath. A mechanic will check all of this before you commit, and give you a concrete basis to negotiate on price. Inspection →
📄 Outstanding finance, insurance write-offs and clocking won't appear in the MOT records — a dedicated history check covers all of this. Our link gets you 20% off automatically. History Get 20% off via CarHunch

Mileage Distribution

Most 2020 Mercedes Benz Gls 400 Amg Line Prem D 4mat A vehicles sit in the blue band. If the vehicle you're looking at is outside it, it's either unusually low or high mileage for its age.

39,733

typical

27,331

low mileage

50,572

high mileage

Half of all 2020 Mercedes Benz Gls 400 Amg Line Prem D 4mat A vehicles fall between 27,331 and 50,572 miles.

Is the mileage you're seeing normal?

✓ Under 27,331 miles — lower than most. Could be great, or could be a vehicle that rarely moved. Check test frequency and mileage progression in the MOT history.

✓ 27,331–50,572 miles — normal for age. This is where most 2020 Mercedes Benz Gls 400 Amg Line Prem D 4mat As sit.

⚠ Over 68,272 miles — higher than typical. Not necessarily a problem, but check service history and look out for advisory build-up on tyres and brakes.

2020 Mercedes Benz Gls 400 Amg Line Prem D 4mat A — Still on the Road

Almost all 2020 Mercedes Benz Gls 400 Amg Line Prem D 4mat As are still on the road.

Strong survival — 122 vehicles still getting MOTs in 2025, 92% of the peak.

Based on vehicles from this manufacture year that had at least one MOT test in each calendar year. Data from 2022–2025.

MOT History Averages

2.8

Avg MOT tests per vehicle

0.3

Avg failures per vehicle

1.7

Avg advisories per vehicle

Compare with another model

See how the 2020 Mercedes Benz Gls 400 Amg Line Prem D 4mat A stacks up against a rival.

A solid choice — agree?