MERCEDES S-CLASS (1991)
Running costs, common problems, and reliability data based on 118 real MOT tests in 2024.
MOT Pass Rate
92%
Total Tests (2024)
118
Avg Mileage
120,508 mi
Est. Annual Cost
£2,097
Is the 1991 MERCEDES S-CLASS reliable?
Excellent reliability. Very few MOT failures. That's 10 points above the national average of 82%. It also outperforms the MERCEDES brand average of 87%.
At 33 years old, 92% of MERCEDES S-CLASSs from 1991 passed their MOT first time in 2024. That's based on 118 tests across the UK. The average mileage at this age is 120,508 miles.
How does the 1991 MERCEDES S-CLASS compare?
Mileage Analysis
The average 1991 MERCEDES S-CLASS has 120,508 miles on the clock, which is significantly below the expected 244,200 miles for a 33-year-old car. Low-mileage examples may have spent time sitting unused, so check for issues like corroded brakes or perished rubber seals.
Best year to buy a MERCEDES S-CLASS?
The most reliable year is the 2020 model with a 95% MOT pass rate, while the 1992 model has the lowest at 72%. The 1991 sits between the two at 92%.
How much does a 1991 MERCEDES S-CLASS cost to run?
Based on 7,400 miles/year (UK average), current fuel prices, and repair likelihood from MOT pass rate data. Insurance not included.
MERCEDES S-CLASS by Year
| Year | Pass Rate | Tests | Avg Mileage |
|---|---|---|---|
| 2021 | 91% | 164 | 32,036 mi |
| 2020 | 95% | 540 | 43,972 mi |
| 2019 | 94% | 5,921 | 67,860 mi |
| 2018 | 94% | 6,518 | 75,456 mi |
| 2017 | 93% | 5,990 | 73,988 mi |
| 2016 | 91% | 6,819 | 74,260 mi |
| 2015 | 92% | 5,513 | 87,325 mi |
| 2014 | 92% | 3,915 | 95,545 mi |
| 2013 | 89% | 2,145 | 108,065 mi |
| 2012 | 88% | 2,817 | 100,420 mi |
| 2011 | 87% | 2,202 | 117,628 mi |
| 2010 | 85% | 2,001 | 110,934 mi |
| 2009 | 82% | 1,990 | 114,274 mi |
| 2008 | 84% | 2,232 | 110,584 mi |
| 2007 | 84% | 2,940 | 117,418 mi |
| 2006 | 87% | 2,334 | 111,043 mi |
| 2005 | 84% | 1,301 | 132,014 mi |
| 2004 | 82% | 1,158 | 124,020 mi |
| 2003 | 82% | 1,227 | 120,882 mi |
| 2002 | 79% | 720 | 115,052 mi |
| 2001 | 79% | 735 | 107,381 mi |
| 2000 | 81% | 562 | 102,703 mi |
| 1999 | 78% | 434 | 98,447 mi |
| 1998 | 81% | 522 | 111,371 mi |
| 1997 | 86% | 373 | 107,182 mi |
| 1996 | 83% | 348 | 109,185 mi |
| 1995 | 86% | 286 | 111,087 mi |
| 1994 | 92% | 140 | 106,787 mi |
| 1993 | 76% | 49 | 112,335 mi |
| 1992 | 72% | 121 | 119,350 mi |
| 1991 | 92% | 118 | 120,508 mi |
| 1990 | 87% | 125 | 142,121 mi |
Checking a specific MERCEDES S-CLASS?
Enter the reg plate to see its individual MOT history, mileage verification, and predicted costs.
About the 1991 MERCEDES S-CLASS
The 1991 MERCEDES S-CLASS is a large car with a 2962cc petrol engine. 118 of these vehicles were MOT tested in 2024, making it a rare model on UK roads. It ranks in the top 9% of all 1991 cars for reliability.
With an average of 120,508 miles at 33 years old, MERCEDES S-CLASS 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.
1991 MERCEDES S-CLASS Fuel Costs
The 2962cc petrol engine is on the larger side, so fuel won't be this car's strong point. Expect around 30 mpg in mixed driving, which works out to roughly £1,592 per year at current petrol prices of 142p per litre (based on 7,400 miles per year).
What does it cost to own a 1991 MERCEDES S-CLASS?
Total estimated annual running cost is £2,097 (£175/month), broken down as £1592 fuel, £250 road tax, £55 MOT, and £200 predicted repairs. The low repair estimate reflects the excellent 92% pass rate. These cars rarely fail their MOT, so unexpected bills are less likely.
MERCEDES S-CLASS Reliability Trend
Newer MERCEDES S-CLASSs show better MOT pass rates than older ones, with an average improvement of 6 percentage points.
Buying a Used 1991 MERCEDES S-CLASS
At 33 years old, the MERCEDES S-CLASS is firmly in budget territory. Purchase prices are low, but check for rust, worn suspension bushes, and electrical gremlins. A full service history is especially valuable at this age. If you're flexible on year, the 2020 model has the highest pass rate at 95%.
Alternatives to the 1991 MERCEDES S-CLASS
The MERCEDES S-CLASS is actually the most reliable option among similar petrol large cars from this era. Here are comparable petrol cars with similar engines:
- MERCEDES 300 (1992) 83% pass rate (-9%) from 1,096 tests
- PORSCHE 911 (1991) 91% pass rate (-1%) from 929 tests
- PORSCHE 944 (1990) 85% pass rate (-7%) from 914 tests
- PORSCHE 968 (1993) 85% pass rate (-7%) from 489 tests