1978 Mercedes Sl 350 MOT Pass Rate
Pass rate for Sl 350 models manufactured in 1978, based on 145 real MOT test results.
Data from official DVSA MOT testing records
1978 Mercedes Sl 350 MOT Analysis
The 1978 Mercedes Sl 350 has an MOT pass rate of 62.8% based on 145 tests — around the UK average for UK vehicles. Cars of this vintage present for MOT with an average of 97,879 miles on the odometer. With a 37.2% failure rate, the 1978 Sl 350 is rated as "Average" for MOT reliability.
The leading cause of MOT failure for the 1978 Mercedes Sl 350 is Brakes, responsible for 0.7% of failures. Brake-related failures include worn brake pads, corroded brake discs, leaking brake lines, and faulty brake servos. These are safety-critical components — any brake deficiency will result in an MOT fail. Typical repair costs range from £150–400. Noise, emissions and leaks is the second most common issue at 0.7%.
Top failures specific to 1978 models only. The overall Sl 350 page may show different rankings.
What Fails Most
What Fails on This Car?
Click a category to see specific failure items.
View as table
| Rank | Failure Category | Rate (%) | Count |
|---|---|---|---|
| 1 | Brakes | 0.7% | 1 |
| 2 | Noise, Emissions And Leaks | 0.7% | 1 |
Failures per 10,000 Miles
avg. 97,879 miFor every 10,000 miles driven, this shows what percentage of MOT tests fail for each category. This accounts for how far cars are actually driven, not just raw pass/fail counts.
View as table
| Category | Rate / 10K mi | Raw % | Count |
|---|---|---|---|
| Brakes | 0.07 | 0.7% | 1 |
| Noise, emissions and leaks | 0.07 | 0.7% | 1 |
Mileage Statistics
Mileage-adjusted failure rate — accounts for how much this model year is typically driven.
About This Data
The 1978 Mercedes Sl 350 has an MOT pass rate of 62.8% based on 145 tests — around the UK average for UK vehicles. Cars of this vintage present for MOT with an average of 97,879 miles on the odometer. With a 37.2% failure rate, the 1978 Sl 350 is rated as "Average" for MOT reliability.
If you own or are considering buying a 1978 Mercedes Sl 350, budget for potential repairs before each MOT. Before your MOT, pay particular attention to brakes: Listen for squealing or grinding noises. Check brake pedal feel — if it feels spongy or goes to the floor, have the system inspected immediately. Look at brake pad thickness through the wheel spokes (minimum 3mm). With an average mileage of 97,879 miles, these vehicles are in the higher-mileage bracket where wear-related failures become more common.
Brakes — 0.7% of failures
Brakes issues account for 0.7% of MOT failures on 1978 Mercedes Sl 350 models. Brake-related failures include worn brake pads, corroded brake discs, leaking brake lines, and faulty brake servos. These are safety-critical components — any brake deficiency will result in an MOT fail. Typical repair costs: £150–400. Pre-MOT check: Listen for squealing or grinding noises. Check brake pedal feel — if it feels spongy or goes to the floor, have the system inspected immediately. Look at brake pad thickness through the wheel spokes (minimum 3mm).
Noise, emissions and leaks — 0.7% of failures
Noise, emissions and leaks issues account for 0.7% of MOT failures on 1978 Mercedes Sl 350 models. Emissions failures occur when exhaust gases exceed legal limits for carbon monoxide (CO), hydrocarbons (HC), or particulate matter (diesel). Common causes include faulty oxygen sensors, clogged catalytic converters, or DPF issues on diesel vehicles. Typical repair costs: £100–1,000+. Pre-MOT check: If the engine management light is on, get it diagnosed before the MOT. For diesel cars, ensure the DPF has completed a regeneration cycle. Regular servicing and using premium fuel before the test can help.
Based on DVSA anonymised MOT test data (2005–2024). Crown copyright, Open Government Licence v3.0.