Sports car and convertible · 1996–2021 cars

Porsche 911 reliability

The Porsche 911 fails 10.4% of first MOT tests, 62% fewer MOT fails than the average car its age and mileage, based on 177,861 DVSA MOT tests from 2022 to 2024.

Better than averageReliability score 99/100#13 of 62 sports car and convertibles

Checking a Porsche 911 before you buy?

first-time MOT fail rate (all cars: 28.4%): 10.4%; first-time MOT fail rate (all cars: 28.4%)
fails than cars of the same age and mileage: 62% fewer; fails than cars of the same age and mileage
MOT tests analysed, 2022 to 2024: 177,861; MOT tests analysed, 2022 to 2024
typical miles a year, from MOT readings: 3,800; typical miles a year, from MOT readings

What this means for buyers

The Porsche 911 is a sound buy on the MOT evidence. The first-time MOT fail rate is 10.4%, against 28.4% for all cars. It has 62% fewer MOT fails than cars of the same age and mileage, and ranks 13 of 62 sports car and convertible models. That is based on 177,861 tests from 2022 to 2024.

Age still matters. Cars from 2013 did best, with 76% fewer MOT fails than cars of the same age and mileage. Cars from 1998 were the weakest, at 46% fewer, so a 1998 car needs closer inspection. Whatever the year, check four things. Make sure the lambda reading is within specified limits, the most common failure at 0.86% of tests. Check the CV joint boots are not split or insecure, that every position lamp works, and that the headlamp aim is not set too high.

MOT fail rate by age

How the Porsche 911 ages

Each point is the share of Porsche 911s of that age that failed their MOT first time, against all cars of the same age.

Porsche 911All cars

Porsche 911 first-time MOT fail rate by age
Age at MOT (years)	Porsche 911	All cars
3	4.4%	12.3%
4	4.1%	14.1%
5	4.6%	16.4%
6	4.4%	19.1%
7	4.5%	22.1%
8	4.4%	25.5%
9	4.9%	28.8%
10	6.6%	31.8%
11	7.1%	34.6%
12	7.2%	37.3%
13	8.3%	39.5%
14	10.3%	41.1%
15	12.1%	42.3%
16	13.1%	42.9%
17	13.6%	43.4%
18	15%	43.5%
19	16.6%	43.4%
20	17.6%	42.8%
21	19%	41.4%
22	18.3%	40.6%
23	18.5%	38.9%
24	18.9%	37.1%
25	17.6%	35.8%

By year

The best and worst Porsche 911 years

2013 cars come out best and 1998 cars worst, once age and mileage are taken into account.

Porsche 911 MOT results by year of first registration
First registered	Tests	Fail rate	Against same-age cars	Typical mileage
2021 911	1,505	3.4%	62% fewer fails	12,069
2020 911	5,035	3.5%	62% fewer fails	14,593
2019 911	10,341	3.9%	63% fewer fails	17,456
2018 911	11,299	5.2%	54% fewer fails	15,273
2017 911	9,645	4.1%	70% fewer fails	22,327
2016 911	8,569	4.3%	71% fewer fails	25,468
2015 911	8,019	4.2%	76% fewer fails	29,227
2014 911	7,663	5.3%	71% fewer fails	28,534
2013 911	5,830	5.5%	76% fewer fails	39,397
2012 911	6,950	7%	73% fewer fails	46,163
2011 911	4,867	6.5%	75% fewer fails	40,688
2010 911	6,721	8.3%	71% fewer fails	45,895
2009 911	5,659	9.7%	71% fewer fails	55,933
2008 911	7,184	11.7%	65% fewer fails	53,931
2007 911	9,525	12.4%	64% fewer fails	58,535
2006 911	10,443	13.6%	64% fewer fails	65,091
2005 911	10,113	14.2%	63% fewer fails	69,583
2004 911	9,212	16%	59% fewer fails	71,054
2003 911	9,680	18.3%	54% fewer fails	76,057
2002 911	9,155	18.4%	54% fewer fails	81,765
2001 911	5,505	18.2%	54% fewer fails	85,380
2000 911	3,504	19.9%	48% fewer fails	87,432
1999 911	5,657	19%	49% fewer fails	93,009
1998 911	4,233	19.7%	46% fewer fails	96,838
1997 911	1,067	14.3%	57% fewer fails	73,375
1996	480	11.5%	65% fewer fails	77,014

Common problems

What fails most on a Porsche 911

Failures by area, against cars of the same age and mileage.

Fail rate by area

Lights and electrics3.9%65% below avg
Tyres2.3%52% below avg
Exhaust, emissions and leaks1.7%51% below avg
Brakes1.7%75% below avg
Suspension1.4%84% below avg
Body, chassis and structure1.4%67% below avg
Windscreen, wipers and mirrors1.1%78% below avg
Number plates and VIN0.5%22% above avg
Seat belts and airbags0.3%79% below avg

Average for cars of the same age and mileage

Top MOT failures

1
Lambda reading outside specified limits 0.86% of tests
An out-of-range lambda reading suggests poor fuel mixture or a failing catalytic converter, so diagnosis is needed.
2
CV joint boot split or insecure 0.67% of tests
A split CV boot lets dirt in and grease out, so the joint wears and may need full replacement.
3
Position lamp not working 0.66% of tests
A failed position lamp makes the car harder to see in poor light and is illegal, so it must be repaired.
4
Headlamp aim set too high 0.65% of tests
Headlamps aimed too high can dazzle other drivers, and adjusting them is usually a quick job.
5
Tyre ply or cords exposed 0.55% of tests
Exposed ply or cords can let the tyre fail suddenly, so the tyre must be replaced before the car is driven.
6
Tyre tread below 1.6mm 0.55% of tests
Tread below 1.6mm is illegal and reduces grip in wet conditions, so the tyre must be replaced.
7
Rigid brake pipe excessively corroded 0.53% of tests
Badly corroded brake pipes can leak or fail, which can cause a loss of braking, so repair is urgent.
8
Tyre cut reaching ply or cords 0.49% of tests
A cut reaching the ply or cords weakens the tyre and can cause a burst, so it must be replaced.

Most common advisories

Not a fail yet, but worth pricing in: these show up on a Porsche 911's MOT certificate most often.

Tyre worn close to legal limit5.61%
Brake pipes corroded and greasy4.54%
Brake disc pitted or scored3.83%
Tyre slightly damaged or cracking3.06%
Engine oil leak, not excessive1.95%
Nail in tyre, monitor1.05%

Before you buy

What to check on a used Porsche 911

1
Lambda reading outside specified limits
An out-of-range lambda reading suggests poor fuel mixture or a failing catalytic converter, so diagnosis is needed.
2
CV joint boot split or insecure
A split CV boot lets dirt in and grease out, so the joint wears and may need full replacement.
3
Position lamp not working
A failed position lamp makes the car harder to see in poor light and is illegal, so it must be repaired.
4
Headlamp aim set too high
Headlamps aimed too high can dazzle other drivers, and adjusting them is usually a quick job.
5
Every MOT since new
Look for the faults above coming back year after year: it shows how the car has been looked after.
6
The mileage record
A typical Porsche 911 covers about 3,800 miles a year. A big gap or a drop between MOTs is a warning sign.
7
Finance, stolen and write-off
The records the MOT can't show. A Full Check (£9.99) covers all three before you hand over any money.

Fuel types tested

Petrol99.8%
LPG0.2%
Diesel0%
Other0%

Most common colours

Black, Silver, Grey, Blue, White

Average engine size: 3.5 litres.

Compare

How the Porsche 911 compares with its rivals

Porsche 911 against similar models
Model	Fail rate	Against same-age cars
Porsche 911	10.4%	62% fewer MOT fails than the average car its age
Mercedes-Benz SL	15.3%	51% fewer MOT fails than the average car its age
Porsche Boxster	16.4%	48% fewer MOT fails than the average car its age
BMW Z4	22.2%	33% fewer MOT fails than the average car its age
Audi TT	22.6%	29% fewer MOT fails than the average car its age
Mercedes-Benz SLK	25.9%	21% fewer MOT fails than the average car its age
Mazda MX-5	25.3%	16% fewer MOT fails than the average car its age

Every sports car and convertible ranked in the sports car and convertible reliability index, or all Porsche models.

Questions

Porsche 911 questions, answered

Is the Porsche 911 reliable?

On MOT results, the Porsche 911 is better than average: it fails 10.4% of first MOT tests, 62% fewer MOT fails than the average car its age and mileage. It ranks 13 of 62 sports car and convertible models in our index.

What fails most on a Porsche 911 MOT?

The most common MOT failures on the Porsche 911 are lambda reading outside specified limits (0.86% of tests), cv joint boot split or insecure (0.67% of tests), position lamp not working (0.66% of tests). By area, lights and electrics fails 3.9% of its tests.

Which Porsche 911 year is the most reliable?

Among years with 1,000+ tests, 2013 cars do best (76% fewer MOT fails than the average car its age) and 1998 cars do worst (46% fewer MOT fails than the average car its age).

How many miles does a Porsche 911 do a year?

A typical Porsche 911 covers about 3,800 miles a year, from the mileage recorded at its MOTs. Check the car you're looking at against that with a free mileage check.

How do I check a Porsche 911 before I buy it?

Enter its registration for a free check of its MOT history, mileage, ULEZ status and tax. Before you pay, a Full Check (£9.99) shows outstanding finance, stolen and write-off records.

Source: DVSA anonymised MOT test results, 2022 to 2024, class 4 vehicles aged 3 to 25, normal tests only. How we compare like with like: our methodology.

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