Mercedes 300 D Auto (1984)
1984 Mercedes 300 D Auto
CarHunch analysed 129 real MOT records for the 1984 Mercedes 300 D Auto. This breakdown of actual test outcomes — pass rates, defect profiles, mileage data — isn't published anywhere else.
This 1984 Mercedes 300 D has a first-time MOT pass rate of just 40%, less than half the UK average of 80%, making it a significantly higher-risk proposition for buyers. The good news is that dangerous defects are absent from this cohort (0%), and vehicles rarely fail outright—averaging only 0.01 failures per car—suggesting any issues tend to be minor rather than safety-critical.
These cars are running at 255,000 miles on average, which is genuinely high mileage for a 40-year-old vehicle, yet the minimal failure rate suggests the survivors in this dataset are mechanically sound despite their age and distance. Before committing to purchase, have a pre-buy inspection completed by a diesel specialist familiar with older Mercedes engines, as the low pass rate likely reflects worn ancillaries and gaskets rather than catastrophic mechanical failure.
What to check before buying a 1984 Mercedes 300 D Auto
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.
- 📄 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 300 D Auto
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Pass Rate by Fuel Type
| Fuel type | Vehicles | Pass rate | Avg failures |
|---|---|---|---|
| Diesel (98%) | 126 | 0.4% | 0.01 |
| Petrol (2%) | 3 | 0% | 0 |
Mileage Distribution
Most 1984 Mercedes 300 D Auto 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 1984 Mercedes 300 D Auto vehicles fall between 255,135 and 255,135 miles.
MOT History Averages
Found a specific Mercedes 300 D Auto?
Enter the reg to see its individual MOT history, AI Hunches, and how it compares to this cohort.