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MG Mgb GT Reliability, MOT Pass Rate & Common Faults

Free MG Mgb GT car check

Is the MG Mgb GT reliable? We analysed 3,633 real MOT tests across 342 vehicles to find out.

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Data last updated: · Based on 3,633 real MOT tests
MOT Pass Rate
74.8%
Typical Mileage
44,148mi
Annual Mileage
484mi/yr
Est. Lifespan
60yrs

The MG Mgb GT is about average for reliability based on real UK MOT data. Common problems include parking brake: efficiency below requirements, windscreen washer provides insufficient washer liquid and brake binding. Here's everything you need to know before buying a used MG Mgb GT.

MG Mgb GT Number Plates

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

MG Mgb GT MOT Pass Rate by Year

How likely is a MG Mgb GT to pass its MOT? Here's the pass rate for each registration year, newest first.

73.3%
1981
75.6%
1980
72.4%
1979
69.8%
1978
68.9%
1977
75.5%
1976
65.1%
1975
79.9%
1974
76.2%
1973
75.8%
1972
74.2%
1971
78.6%
1970
73.1%
1969
74.8%
1968
78%
1967
80.4%
1966

MG Mgb GT Problems — What Goes Wrong?

The most common reasons a MG Mgb GT fails its MOT, ranked by how often they occur. Check for these problems before you buy.

Parking brake: efficiency below requirements 113
Windscreen washer provides insufficient washer liquid 108
brake binding 88
Suspension spring mounting prescribed area is excessively corroded 70
Stop lamp not working 69
Steering rack gaiter split 68
Suspension component mounting prescribed area is excessively corroded 65
Seat belt anchorage prescribed area is excessively corroded 62
position lamp(s) not working 61
Windscreen wiper does not clear the windscreen effectively 60

MG Mgb GT Mileage — What's Normal?

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

Low usage
153 mi/yr
Typical
484 mi/yr
Average
1,041 mi/yr
Heavy usage
1,112 mi/yr

MG Mgb GT MOT Data by Registration Year

Full breakdown of pass rate and mileage for each year. Use this to compare the MG Mgb GT year you're looking at.

Year Tests Pass Rate Low Mi. Typical Mi. High Mi.
1981 135 73.3% 37,926 49,831 57,228
1980 119 75.6% 38,334 57,648 86,717
1979 217 72.4% 16,561 32,044 60,290
1978 242 69.8% 16,451 68,395 79,133
1977 190 68.9% 20,990 44,445 77,438
1976 110 75.5% 55,025 71,728 78,786
1975 175 65.1% 15,756 50,561 83,352
1974 244 79.9% 30,562 48,092 78,325
1973 336 76.2% 7,418 32,713 61,930
1972 533 75.8% 13,964 41,124 64,489
1971 252 74.2% 9,231 20,291 69,056
1970 192 78.6% 22,220 51,800 59,530
1969 212 73.1% 13,216 50,836 75,754
1968 226 74.8% 23,942 68,511 86,268
1967 205 78.0% 22,279 52,239 76,309
1966 92 80.4% 18,873 26,479 61,120

How Long Does a MG Mgb GT Last?

Based on 342 MG Mgb GT vehicles on UK roads.

Average
42.5 years
Median
44.0 years
Estimated max lifespan
60 years

MG Mgb GT Mileage Distribution

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

Median
44,148 mi
75th Percentile
72,214 mi
95th Percentile
93,478 mi
Max Recorded
654,438 mi

Best Year to Buy a Used MG Mgb GT

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

Best year
1966

80.4% MOT pass rate from 92 tests

Year to avoid
1975

65.1% MOT pass rate from 175 tests

The best year to buy a used MG Mgb GT is 1966, which has the highest MOT pass rate at 80.4% across 92 tests. The 1975 model year has the lowest pass rate at 65.1% — if you're looking at one from that year, budget for potential repairs and get a thorough pre-purchase inspection.

How Does the MG Mgb GT Compare?

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

Model Pass Rate Tests Typical Mileage Lifespan
MG Mgb GT THIS CAR 74.8% 3,633 44,148 mi 60 yrs
MG Zr 69.8% 651,705 57,257 mi 25 yrs
MG Mgf 66.7% 546,238 62,469 mi 31 yrs
MG Tf 72.8% 475,348 45,249 mi 24 yrs
Triumph Daytona 955I 85.7% 1,279 13,990 mi 27 yrs

Compared to the MG Zr (69.8% pass rate) and the MG Mgf (66.7% pass rate), the MG Mgb GT outperforms both on MOT reliability.

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Should you buy a used MG Mgb GT?

The MG Mgb GT has an overall MOT pass rate of 74.8% across 3,633 real MOT tests — roughly in line with the UK average.

The most common problems on the MG Mgb GT are parking brake: efficiency below requirements (113 recorded failures), windscreen washer provides insufficient washer liquid (108), and brake binding (88). 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 MG Mgb GT owner drives around 484 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 MG Mgb GT models stay on UK roads for around 60 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.

MG Mgb GT — Frequently Asked Questions

Is the MG Mgb GT reliable?
Based on 3,633 MOT tests, the MG Mgb GT has a 74.8% pass rate — about average for UK cars.
What are the common problems on a MG Mgb GT?
The most common MOT failures are parking brake: efficiency below requirements, windscreen washer provides insufficient washer liquid, and brake binding. Check these on any test drive.
How many miles does a MG Mgb GT do per year?
The typical MG Mgb GT does around 484 miles per year. Anything significantly above or below this is worth investigating.
How long does a MG Mgb GT last?
Most MG Mgb GT models stay on UK roads for around 60 years based on our analysis of 342 vehicles.
Should I get a vehicle check before buying a MG Mgb GT?
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 MG Mgb GT?
Based on MOT pass rates, the best year to buy a used MG Mgb GT is 1966 with a 80.4% pass rate across 92 tests.