Mercedes Auto-Sleepers (2021)
Estimated running costs and MOT pass rates from 36 MOT tests in 2024.
Annual Cost
£2,281
£190/month
MOT Pass Rate
89%
Good
Road Tax
£200
Standard rate/year
Est. Insurance
n/a
2143cc Diesel
Solid Option
89% pass rate, £2,281/year to run. 7 points above average.
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Annual Running Costs
~40 mpg
Car rate estimate; motorhomes are taxed differently
Estimates based on 7,400 miles/year (UK average), diesel at 199.33p a litre (GOV.UK weekly average, week of 19 October 2026), GOV.UK road tax rates and repair likelihood from MOT data. Insurance not included. Cars registered from April 2017 pay the £200 standard rate, plus £440 a year for five years (from the second year) if they cost over £40,000 new (over £50,000 for electric cars).
Reliability Verdict
Good reliability. Occasional issues but generally solid. That's 7 points above the average of 82% across all models in our data.
89% of MOT tests on Mercedes Auto-Sleeperss from 2021 ended in a pass in 2024, when they were about 3 years old. That's based on 36 tests across the UK, retests included. The average mileage recorded at those tests was 8,241 miles.
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How Does It Compare?
Mileage Analysis
8,241
Average miles
22,200
Expected for age
The average 2021 Mercedes Auto-Sleepers had 8,241 miles on the clock at its 2024 MOT, which is significantly below the expected 22,200 miles for a 3-year-old car. Low-mileage examples may have spent time sitting unused, so check for issues like corroded brakes or perished rubber seals.
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Mercedes Auto-Sleepers by Year
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About the 2021 Mercedes Auto-Sleepers
The 2021 Mercedes Auto-Sleepers is a motorhome. Our records list a 2143cc diesel engine, though engines vary between versions. 36 MOT tests were recorded on this model in 2024, making it a rare model on UK roads. It sits in the bottom 18% of 2021 models for MOT pass rate.
With an average of 8,241 miles recorded at its 2024 MOT tests, Mercedes Auto-Sleepers owners tend to use this car less than the typical driver. Very low mileage could mean the car has been garaged or used only for short trips, which can cause its own issues like battery drain and moisture buildup.
2021 Mercedes Auto-Sleepers Fuel Costs
The 2143cc diesel engine offers a reasonable balance between performance and economy. Expect around 40 mpg in mixed driving, which works out to roughly £1,676 per year with diesel at 199.33p per litre (GOV.UK weekly average, week of 19 October 2026; based on 7,400 miles per year). Diesel cars of this age should have their DPF (diesel particulate filter) checked, as replacements can be costly.
What does it cost to own a 2021 Mercedes Auto-Sleepers?
Total estimated annual running cost is £2,281 (£190/month), broken down as £1,676 fuel, £200 road tax, £55 MOT, and £350 predicted repairs. Repair costs are moderate, reflecting the 89% pass rate. Keeping on top of servicing will help avoid surprises.
Buying a Used 2021 Mercedes Auto-Sleepers
At 5 years old, the Mercedes Auto-Sleepers offers good value with plenty of life remaining. Most manufacturer warranties will have expired, so a pre-purchase inspection is worth the cost. Note: with only 36 tests in our data, these figures should be treated as indicative rather than definitive.
Common Issues to Watch For
These are typical issues for cars of this age, fuel type and engine size, not faults recorded on this model's MOT tests. Use them as a checklist when you view one.
DPF (Diesel Particulate Filter)
Watch outShort journeys clog the DPF. Replacement costs £1,000-£2,500. Check the DPF warning light and ask about driving patterns.
Turbo Wear
Medium riskDiesel turbos work harder and wear faster. Listen for whining noises and check for oil leaks around the turbo housing.
AdBlue System
Medium riskPost-2015 diesels use AdBlue for emissions. Sensor failures and tank heater issues are common. Budget £200-£500 for repairs.
EGR Valve
Low riskExhaust Gas Recirculation valves clog with carbon deposits, causing rough running and poor economy. Cleaning costs £150-£300, replacement £300-£600.
Dual Mass Flywheel
Medium riskLarger diesel engines put extra strain on the dual mass flywheel. Listen for rattling at idle. Replacement with clutch is £800-£1,500.
Service History
Low riskAlways request a full service history. Regular servicing is the single best indicator of how well a car has been maintained, regardless of mileage.
Running Costs Compared
How the 2021 Mercedes Auto-Sleepers stacks up against similar cars for estimated annual running costs, insurance group, and tax.
| Car | Pass Rate | Fuel/yr | Tax/yr | Est. Ins. Group | Total/yr |
|---|---|---|---|---|---|
| Mercedes Auto-Sleepers(2021) | 89% | £1,676 | £200 | n/a | £2,281 |
| Ford Transit Custom(2019) | 87% | £1,397 | £200 | n/a | £2,002-£279 |
| Volkswagen Transporter(2019) | 88% | £1,397 | £200 | n/a | £2,002-£279 |
Estimates based on 7,400 miles/year, GOV.UK average pump prices for the week of 19 October 2026, GOV.UK road tax rates and MOT data. Insurance groups are our rough estimate from engine size, not official groups. Actual costs vary by driver, location, and usage.
Questions about the 2021 Mercedes Auto-Sleepers
Is the 2021 Mercedes Auto-Sleepers reliable?
Good reliability. Occasional issues but generally solid. 89% of MOT tests on 2021 Mercedes Auto-Sleeperss ended in a pass, from 36 tests (DVSA MOT data for tests in 2024, retests included). That's 7 points above the average of 82% across all models in the same data.
How much does a 2021 Mercedes Auto-Sleepers cost to run?
Our estimate is £2,281 a year (£190 a month): £1,676 fuel, £200 road tax, £55 MOT and £350 predicted repairs, based on 7,400 miles a year. Insurance is not included.
What is the MOT pass rate for a 2021 Mercedes Auto-Sleepers?
89% of 36 MOT tests on the 2021 Mercedes Auto-Sleepers ended in a pass (DVSA MOT data for tests in 2024, retests included). That ranks it 2760th of 3,336 models first registered in 2021 (bottom 18%).
What is the average mileage for a 2021 Mercedes Auto-Sleepers?
The average mileage recorded at MOT tests on the 2021 Mercedes Auto-Sleepers is 8,241 miles, which is significantly below the expected 22,200 miles for a 3-year-old car. Low-mileage examples may have spent time sitting unused, so check for issues like corroded brakes or perished rubber seals.
Related Mercedes Models
Explore other Mercedes cars or similar models in the same category.
Mercedes A
2019 · 1461cc Diesel
Mercedes C
2017 · 1991cc Hybrid
Mercedes A-Class
2017 · 1461cc Diesel
Ford Transit Custom
2019 · 2000cc Diesel
Volkswagen Transporter
2019 · 1968cc Diesel
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