Mercedes Benz Sl (1991)
1991 Mercedes Benz Sl
CarHunch analysed 439 real MOT records for the 1991 Mercedes Benz Sl. This breakdown of actual test outcomes — pass rates, defect profiles, mileage data — isn't published anywhere else.
The 1991 Mercedes-Benz SL passes its MOT slightly above the UK average at 81.9%, which is reassuring for a 33-year-old car, though one in five will have picked up a dangerous defect at some point—a concern worth taking seriously on a pre-purchase inspection. These cars are running at a sensible 87,000 miles on average, suggesting many have been cherished rather than thrashed, yet they still rack up 2.28 failures per test and 13.4 advisories, pointing to age-related wear that catches up with everything eventually.
When you buy one, expect to budget for regular attention: the high advisory count reflects typical issues with aging electrics, seals, and suspension components rather than catastrophic failure. Have a thorough pre-purchase inspection done by a Mercedes specialist, not a generalist, because this generation rewards proper maintenance but punishes neglect.
What to check before buying a 1991 Mercedes Benz Sl
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.
- ⚠️ 20.3% of these vehicles have had a dangerous defect recorded. Enter the reg below — the full MOT history will show exactly what was flagged and whether it was resolved.
- 📄 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
MOT history is one piece of the puzzle. These checks can reveal what CarHunch can't.
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Pass Rate by Fuel Type
| Fuel type | Vehicles | Pass rate | Avg failures |
|---|---|---|---|
| Petrol (100%) | 437 | 81.8% | 2.28 |
| LPG (0%) | 1 | 94.7% | 1 |
| Diesel (0%) | 1 | 88.9% | 1 |
Mileage Distribution
Most 1991 Mercedes Benz Sl 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.
Half of all 1991 Mercedes Benz Sl vehicles fall between 59,959 and 113,776 miles.
1991 Mercedes Benz Sl — Still on the Road
Numbers are declining — 98 vehicles still getting MOTs in 2025 (42% of peak).
Based on vehicles from this manufacture year that had at least one MOT test in each calendar year. Data from 2014–2025.
MOT History Averages
Most Common MOT Issues — 1991 Mercedes Benz Sl
Based on actual MOT test records for this model. Percentage shows how often each item appears across all vehicles in this cohort.
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43.4%
Nearside Rear Tyre worn close to the legal limit
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41.1%
Oil leak
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34.4%
Offside Rear Tyre worn close to the legal limit
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33.2%
Oil leak, but not excessive
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32%
Nearside Front Tyre worn close to the legal limit
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30.3%
Offside Front Tyre worn close to the legal limit
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27.6%
Offside Rear Brake pipe slightly corroded
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25.7%
Nearside Rear Brake pipe slightly corroded
Data covers a 3-year window centred on 1991. Counts include advisories and failures.
Found a specific Mercedes Benz Sl?
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