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Proton Sl Auto Reliability, MOT Pass Rate & Common Faults

Free Proton Sl Auto car check

Is the Proton Sl Auto reliable? We analysed 963 real MOT tests across 184 vehicles to find out.

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Data last updated: · Based on 963 real MOT tests
MOT Pass Rate
72.2%
Typical Mileage
59,589mi
Annual Mileage
3,498mi/yr
Est. Lifespan
32yrs

The Proton Sl Auto is about average for reliability based on real UK MOT data. Common problems include constant velocity joint gaiter split, tyre tread depth below requirements of 1.6mm and brake pipe excessively corroded. Here's everything you need to know before buying a used Proton Sl Auto.

Proton Sl Auto Number Plates

Number plates registered to a Proton Sl Auto. Click on any registration for full vehicle details — including MOT history, mileage records, previous owners and damage history.

Proton Sl Auto MOT Pass Rate by Year

How likely is a Proton Sl Auto to pass its MOT? Here's the pass rate for each registration year, newest first.

69.4%
1996
71.7%
1995
75.3%
1994

Proton Sl Auto Problems — What Goes Wrong?

The most common reasons a Proton Sl Auto fails its MOT, ranked by how often they occur. Check for these problems before you buy.

constant velocity joint gaiter split 55
Tyre tread depth below requirements of 1.6mm 45
Brake pipe excessively corroded 40
Suspension component mounting prescribed area is excessively corroded 26
fog lamp not working 21
Headlamp insecure 18
Windscreen wiper does not clear the windscreen effectively 18
Horn not working 17
Exhaust has a major leak of exhaust gases 16
Exhaust system not adequately supported 16

Proton Sl Auto Mileage — What's Normal?

How many miles does a typical Proton Sl Auto owner drive per year? Use this to check if a car you're looking at has suspiciously low or high mileage.

Low usage
1,946 mi/yr
Typical
3,498 mi/yr
Average
4,512 mi/yr
Heavy usage
5,966 mi/yr

Proton Sl Auto MOT Data by Registration Year

Full breakdown of pass rate and mileage for each year. Use this to compare the Proton Sl Auto year you're looking at.

Year Tests Pass Rate Low Mi. Typical Mi. High Mi.
1996 268 69.4% 44,794 61,100 73,170
1995 382 71.7% 43,964 61,501 79,350
1994 292 75.3% 42,356 57,802 75,543

How Long Does a Proton Sl Auto Last?

Based on 184 Proton Sl Auto vehicles on UK roads.

Average
13.1 years
Median
12.0 years
Estimated max lifespan
32 years

Proton Sl Auto Mileage Distribution

Total mileage recorded across all Proton Sl Auto MOT tests. If the car you're looking at is above the 75th percentile, it's done more miles than most.

Median
59,589 mi
75th Percentile
76,210 mi
95th Percentile
114,106 mi
Max Recorded
487,764 mi

Best Year to Buy a Used Proton Sl Auto

Based on MOT pass rates across all registration years with sufficient test data.

Best year
1994

75.3% MOT pass rate from 292 tests

Year to avoid
1996

69.4% MOT pass rate from 268 tests

The best year to buy a used Proton Sl Auto is 1994, which has the highest MOT pass rate at 75.3% across 292 tests. The 1996 model year has the lowest pass rate at 69.4% — if you're looking at one from that year, budget for potential repairs and get a thorough pre-purchase inspection.

How Does the Proton Sl Auto Compare?

MOT pass rates compared to similar models. Click any model for the full breakdown.

Model Pass Rate Tests Typical Mileage Lifespan
Proton Sl Auto THIS CAR 72.2% 963 59,589 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
Toyota Yaris Sr 82.4% 1,055 83,302 mi — yrs

Compared to the Proton Persona (66.0% pass rate) and the Proton GEN-2 (70.5% pass rate), the Proton Sl Auto outperforms both on MOT reliability.

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Should you buy a used Proton Sl Auto?

The Proton Sl Auto has an overall MOT pass rate of 72.2% across 963 real MOT tests — roughly in line with the UK average.

The most common problems on the Proton Sl Auto are constant velocity joint gaiter split (55 recorded failures), tyre tread depth below requirements of 1.6mm (45), and brake pipe excessively corroded (40). 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 Sl Auto owner drives around 3,498 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 Sl Auto 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.

Proton Sl Auto — Frequently Asked Questions

Is the Proton Sl Auto reliable?
Based on 963 MOT tests, the Proton Sl Auto has a 72.2% pass rate — about average for UK cars.
What are the common problems on a Proton Sl Auto?
The most common MOT failures are constant velocity joint gaiter split, tyre tread depth below requirements of 1.6mm, and brake pipe excessively corroded. Check these on any test drive.
How many miles does a Proton Sl Auto do per year?
The typical Proton Sl Auto does around 3,498 miles per year. Anything significantly above or below this is worth investigating.
How long does a Proton Sl Auto last?
Most Proton Sl Auto models stay on UK roads for around 32 years based on our analysis of 184 vehicles.
Should I get a vehicle check before buying a Proton Sl Auto?
Yes. An MOT pass rate tells you about the model in general, but a vehicle history check reveals the specific car's finance, stolen, write-off and mileage history — things the seller may not disclose.
What is the best year to buy a Proton Sl Auto?
Based on MOT pass rates, the best year to buy a used Proton Sl Auto is 1994 with a 75.3% pass rate across 292 tests.