How much does a 1991 MERCEDES UNCLASSIFIED cost to run?

Estimated annual running cost is £2,535 (£211/month), including £1245 fuel, £735 road tax, £55 MOT, and £500 predicted repairs.

What is the MOT pass rate for a 1991 MERCEDES UNCLASSIFIED?

The 1991 MERCEDES UNCLASSIFIED has a 73% MOT pass rate based on 33 tests in 2026. This ranks 139 out of 179 cars from 1991.

Which year MERCEDES UNCLASSIFIED is most reliable?

The 2021 MERCEDES UNCLASSIFIED has the highest MOT pass rate at 96%. The least reliable year is 1997 at 66%.

MERCEDES UNCLASSIFIED (1991)

Q: Is the 1991 MERCEDES UNCLASSIFIED reliable?

Average reliability. Expect some repairs as it ages. 73% of MERCEDES UNCLASSIFIEDs from 1991 passed their MOT first time in 2026, based on 33 tests. That's 9 points below the national average of 82%.

Q: What is the average mileage for a 1991 MERCEDES UNCLASSIFIED?

The average mileage for a 1991 MERCEDES UNCLASSIFIED is 102,932 miles, which is significantly below the expected 259,000 miles for a 35-year-old car. Low-mileage examples may have spent time sitting unused, so check for issues like corroded brakes or perished rubber seals.

Running costs, reliability data, and common problems from 33 real MOT tests.

Annual Cost

£2,535

£211/month

MOT Pass Rate

73%

Average

Road Tax

£735

Based on CC/year

Insurance

Grp 35-50

5958cc Diesel

Check Carefully

73% pass rate, £2535/year to run. 9 points below average.

Buying this car? Check for finance, write-offs & theft

£4.99

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Diesel5958cc35 years old33 tests103k miles avg

Annual Running Costs

Fuel (Diesel, 5958cc)

~40 mpg

£1,245

Road Tax

Based on 5958cc

£735

MOT Test

£55

Predicted Repairs

Higher estimate due to low pass rate

£500

Total per year£2,535

Per month£211/mo

Per week£49/wk

Based on 7,400 miles/year (UK average), current fuel prices, and repair likelihood from MOT data. Insurance not included.

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Reliability Verdict

73% MOT pass rate(Average)

0%National avg: 82%100%

Average reliability. Expect some repairs as it ages. That's 9 points below the national average of 82%. It falls below the MERCEDES brand average of 87%.

At 35 years old, 73% of MERCEDES UNCLASSIFIEDs from 1991 passed their MOT first time in 2026. That's based on 33 tests across the UK. The average mileage at this age is 102,932 miles.

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How Does It Compare?

Rank among 1991 cars139th of 179(top 78%)

Rank among MERCEDES models1323th of 1,408(top 94%)

vs national average-9%(82% avg)

vs 1991 cars average-5%(78% avg)

vs MERCEDES average-14%(87% avg)

Mileage Analysis

102,932

Average miles

259,000

Expected for age

The average 1991 MERCEDES UNCLASSIFIED has 102,932 miles on the clock, which is significantly below the expected 259,000 miles for a 35-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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Best Year to Buy?

The most reliable year is the 2021 model with a 96% MOT pass rate, while the 1997 model has the lowest at 66%. The 1991 sits between the two at 73%.

MERCEDES UNCLASSIFIED by Year

Year	Pass Rate	Tests	Avg Mileage
2021	96%	270	14,108 mi
2020	93%	237	17,059 mi
2019	95%	176	25,080 mi
2018	92%	202	40,291 mi
2017	91%	200	39,620 mi
2016	87%	326	45,907 mi
2015	91%	252	72,531 mi
2014	86%	289	83,046 mi
2013	89%	245	52,132 mi
2012	89%	185	66,863 mi
2011	90%	126	63,066 mi
2010	92%	98	94,655 mi
2009	79%	174	100,957 mi
2008	79%	354	111,482 mi
2007	81%	259	105,351 mi
2006	81%	240	95,112 mi
2005	79%	273	101,492 mi
2004	79%	298	91,119 mi
2003	73%	178	102,840 mi
2002	84%	214	129,941 mi
2001	73%	107	121,123 mi
2000	73%	195	116,472 mi
1999	78%	223	144,511 mi
1998	81%	155	139,571 mi
1997	66%	65	104,116 mi
1996	66%	101	175,170 mi
1995	78%	45	212,804 mi
1994	74%	86	85,110 mi
1993	89%	47	159,142 mi
1992	60%	40	117,020 mi
1991	73%	33	102,932 mi
1990	83%	58	95,507 mi

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About the 1991 MERCEDES UNCLASSIFIED

The 1991 MERCEDES UNCLASSIFIED is a performance with a 5958cc diesel engine. 33 of these vehicles were MOT tested in 2026, making it a rare model on UK roads. It sits in the bottom 78% of 1991 cars for MOT pass rates.

With an average of 102,932 miles at 35 years old, MERCEDES UNCLASSIFIED 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 UNCLASSIFIED Fuel Costs

The 5958cc diesel engine is on the larger side, so fuel won't be this car's strong point. Expect around 40 mpg in mixed driving, which works out to roughly £1,245 per year at current diesel prices of 148p per litre (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 1991 MERCEDES UNCLASSIFIED?

Total estimated annual running cost is £2,535 (£211/month), broken down as £1245 fuel, £735 road tax, £55 MOT, and £500 predicted repairs. Repair costs are moderate, reflecting the 73% pass rate. Keeping on top of servicing will help avoid surprises.

MERCEDES UNCLASSIFIED Reliability Trend

Newer MERCEDES UNCLASSIFIEDs show better MOT pass rates than older ones, with an average improvement of 13 percentage points.

Buying a Used 1991 MERCEDES UNCLASSIFIED

At 35 years old, the MERCEDES UNCLASSIFIED 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 2021 model has the highest pass rate at 96%. Note: with only 33 tests in our data, these figures should be treated as indicative rather than definitive.

Common Issues to Watch For

Based on the 1991 MERCEDES UNCLASSIFIED's fuel type, age, and engine size, these are the most likely problem areas to check.

DPF (Diesel Particulate Filter)

Watch out

Short journeys clog the DPF. Replacement costs £1,000-£2,500. Check the DPF warning light and ask about driving patterns.

Turbo Wear

Watch out

Diesel turbos work harder and wear faster. Listen for whining noises and check for oil leaks around the turbo housing.

EGR Valve

Watch out

Exhaust Gas Recirculation valves clog with carbon deposits, causing rough running and poor economy. Cleaning costs £150-£300, replacement £300-£600.

Dual Mass Flywheel

Watch out

Larger diesel engines put extra strain on the dual mass flywheel. Listen for rattling at idle. Replacement with clutch is £800-£1,500.

Rust and Corrosion

Watch out

At 10+ years, check wheel arches, sills, subframe, and brake lines for rust. Structural corrosion is an MOT failure. Prevention is far cheaper than repair.