Proton 15 Sl Reliability, MOT Pass Rate & Common Faults
Free Proton 15 Sl car check
Is the Proton 15 Sl reliable? We analysed 298 real MOT tests across 104 vehicles to find out.
Got a specific Proton 15 Sl? Enter the reg for a free check:
The Proton 15 Sl is about average for reliability based on real UK MOT data. Common problems include constant velocity joint gaiter split, brake pipe excessively corroded and tyre tread depth below requirements of 1.6mm. Here's everything you need to know before buying a used Proton 15 Sl.
Proton 15 Sl Number Plates
Number plates registered to a Proton 15 Sl. Click on any registration for full vehicle details — including MOT history, mileage records, previous owners and damage history.
Proton 15 Sl MOT Pass Rate by Year
How likely is a Proton 15 Sl to pass its MOT? Here's the pass rate for each registration year, newest first.
Proton 15 Sl Problems — What Goes Wrong?
The most common reasons a Proton 15 Sl fails its MOT, ranked by how often they occur. Check for these problems before you buy.
Proton 15 Sl Mileage — What's Normal?
How many miles does a typical Proton 15 Sl owner drive per year? Use this to check if a car you're looking at has suspiciously low or high mileage.
Proton 15 Sl MOT Data by Registration Year
Full breakdown of pass rate and mileage for each year. Use this to compare the Proton 15 Sl year you're looking at.
| Year | Tests | Pass Rate | Low Mi. | Typical Mi. | High Mi. |
|---|---|---|---|---|---|
| 1996 | 83 | 66.3% | 56,336 | 69,162 | 95,591 |
| 1995 | 113 | 74.3% | 51,024 | 57,994 | 81,704 |
| 1994 | 95 | 66.3% | 58,034 | 70,598 | 85,012 |
How Long Does a Proton 15 Sl Last?
Based on 104 Proton 15 Sl vehicles on UK roads.
Proton 15 Sl Mileage Distribution
Total mileage recorded across all Proton 15 Sl MOT tests. If the car you're looking at is above the 75th percentile, it's done more miles than most.
Best Year to Buy a Used Proton 15 Sl
Based on MOT pass rates across all registration years with sufficient test data.
74.3% MOT pass rate from 113 tests
66.3% MOT pass rate from 95 tests
The best year to buy a used Proton 15 Sl is 1995, which has the highest MOT pass rate at 74.3% across 113 tests. The 1994 model year has the lowest pass rate at 66.3% — if you're looking at one from that year, budget for potential repairs and get a thorough pre-purchase inspection.
How Does the Proton 15 Sl Compare?
MOT pass rates compared to similar models. Click any model for the full breakdown.
| Model | Pass Rate | Tests | Typical Mileage | Lifespan |
|---|---|---|---|---|
| Proton 15 Sl THIS CAR | 69.1% | 298 | 68,391 mi | 32 yrs |
| Proton Persona | 66% | 104,196 | 68,588 mi | 32 yrs |
| Proton GEN-2 | 70.5% | 59,272 | 46,580 mi | 22 yrs |
| Proton Wira | 70.1% | 57,151 | 47,970 mi | 26 yrs |
| Kia Ceed 2 Ecodynamics CRDI89 | 84.8% | 415 | 107,406 mi | — yrs |
Compared to the Proton Persona (66.0% pass rate) and the Proton GEN-2 (70.5% pass rate), the Proton 15 Sl sits in the middle of the pack on MOT reliability.
Found a Proton 15 Sl you like?
Run a full vehicle history check on the specific car. See finance, stolen, write-off, mileage and MOT data for that exact vehicle.
Check a specific Proton 15 SlShould you buy a used Proton 15 Sl?
The Proton 15 Sl has an overall MOT pass rate of 69.1% across 298 real MOT tests — roughly in line with the UK average.
The most common problems on the Proton 15 Sl are constant velocity joint gaiter split (27 recorded failures), brake pipe excessively corroded (24), and tyre tread depth below requirements of 1.6mm (22). These are the faults most likely to cause an MOT failure on this model, so check for them carefully on any test drive or pre-purchase inspection. Many are wear-and-tear items that can be budgeted for, but a car that's already failing on multiple fronts may signal neglected maintenance.
A typical Proton 15 Sl owner drives around 3,356 miles per year. If the car you're looking at is significantly above this, expect more wear on suspension, brakes and tyres. If it's well below, the vehicle may have been sitting unused — check for perished rubber, corroded discs and stale fluids.
In terms of longevity, most Proton 15 Sl models stay on UK roads for around 32 years — a strong showing that suggests solid build quality and readily available parts. If you're buying one that's already approaching that window, the data suggests it has plenty of life left provided it's been maintained.
Before committing to a purchase, we recommend running a full vehicle history check on the specific car. This will reveal any outstanding finance, stolen markers, write-off history and mileage discrepancies that the seller may not disclose — and that the MOT data alone can't tell you.