MOT advisory explained
“Valve stem slightly damaged”
The smallest part that can appear on an MOT certificate, and one of the cheapest to fix. It is worth more attention than its size suggests, because a tyre valve is usually as old as the tyre it sits in.
The valve is the short rubber stem you connect an air line to. It is pulled through a hole in the wheel and sealed by its own rubber. The tester bent it gently and saw cracks at its base, or found it sitting at an angle. It still holds air, so the car passes.
3.5% fail on a valve at the next test. The more useful figure is 10.3%, the share that fail on a tyre defect of some kind. A cracked valve and a worn-out tyre tend to arrive together, because they were fitted together.
Look at the tyres themselves before you book anything. If they are close to needing replacement anyway, the valve problem solves itself: a new valve is normally fitted with every new tyre. See “tyre worn close to legal limit” for how to judge that.
A “valve stem slightly damaged” advisory means the rubber tyre valve on a wheel is cracked, perished or slightly bent but still holds air, so the car passes. A new valve is a minor job and is normally included when a tyre is replaced, at £70–£100 per tyre fitted. According to DVSA MOT data analysed by PriceMyRepair, 3.5% of 184,267 such advisories failed on a valve at the next test, and 10.3% failed on a tyre defect of some kind.
A small piece of rubber with a hard life
What goes wrong. It perishes. “perished” is by far the most common note testers add, 18,164 times, and nearly all the others are variations: “cracking”, “perishing”, “deteriorated”. The valve is thin rubber, out in the sun and the brake heat, and at motorway speed it is being flung outwards hard enough to flex at its base on every revolution.
Why it matters. A valve that cracks through lets the tyre down, and it can do it quickly. Most slow deflations give you warning. A valve that splits at the base on a fast road may not.
Rubber or sensor. Many cars made in the last decade have tyre pressure sensors built into the valve. Those usually have a metal stem, which corrodes instead of perishing, and they are serviced with a new seal and core instead of being thrown away. If your car has them, say so when you ask for a price.
Will it fail next year?
This is a rare advisory, recorded 463,672 times, and 184,267 of those can be followed to the next MOT on the same car.
| What happened at the next test | Share |
|---|---|
| Failed on the same component | 3.5% |
| Failed on anything under defect 5.2.3 | 10.3% |
| Same advisory recorded again | 13.4% |
According to DVSA MOT data analysed by PriceMyRepair: 184,267 advisories followed to the same vehicle’s next test. Rows can overlap.
The gap between the two failure rows is the interesting part. Few cars fail on the valve itself. About one in ten fails on a tyre defect, which is roughly what happens after the main tyre advisories: 10.0% for tyres near the legal limit and 9.2% for cracked ones.
So a car with this advisory goes on to fail on its tyres about as often as a car with a tyre advisory. The likely reason is age. Rubber valves are replaced with the tyres, and one that has had time to perish has been on the wheel for a good many years.
| Advisory wording | Fails on same part | Fails under same code | Advised again | Followed |
|---|---|---|---|---|
| Tyre has a cut | 10.8% | 10.8% | 9.8% | 2,198,577 |
| Tyre worn close to legal limit/worn on edge | 10.0% | 10.0% | 22.0% | 32,463,345 |
| Tyre slightly damaged/cracking or perishing | 9.2% | 9.3% | 24.4% | 14,917,627 |
| Wheel bearing has slight play | 5.8% | 5.8% | 26.4% | 1,109,766 |
| Brake hose slightly deteriorated | 5.1% | 5.1% | 33.8% | 735,057 |
| Valve stem slightly damaged | 3.5% | 10.3% | 13.4% | 184,267 |
| Road wheel slightly distorted | 1.0% | 1.0% | 29.6% | 1,628,156 |
It follows the age of the car closely, from 0.3 per 1,000 tests at 3–4 years to 2.0 at 20 years and over, and the share that fail on a valve next time rises gently with it, from 2.7% to 4.2%.
| Age of car | Per 1,000 tests | Fails on same part | Followed |
|---|---|---|---|
| 3–4 years | 0.3 | 2.7% | 8,044 |
| 5–6 years | 0.6 | 3.3% | 17,685 |
| 7–9 years | 0.9 | 3.2% | 39,512 |
| 10–12 years | 1.2 | 3.6% | 42,999 |
| 13–15 years | 1.4 | 3.6% | 34,625 |
| 16–19 years | 1.6 | 4.2% | 24,813 |
| 20 years and over | 2.0 | 4.1% | 12,891 |
Rubber perishes fastest on cars that stand. Tyres and valves on a car driven every day are flexed, warmed and replaced on a normal cycle. On a car that does two thousand miles a year they sit in the weather for a decade.
If this advisory is on your certificate, check the date codes on all four tyres. There is a fair chance they are older than you think.
Do not wait for the next tyre change if the tyres are nearly new and the valves are not. It happens when a fitter reuses old valves, and it is worth the small cost of putting right.
Exact wording on your certificate
Damaged and misaligned are recorded separately but share a code. Misaligned usually means the stem has been pulled to one side by a wheel trim or a careless air line.
| Line on the certificate | Result | Code |
|---|---|---|
| Valve stem slightly damaged | Advisory — pass | 5.2.3 (j) |
| Valve stem slightly misaligned | Advisory — pass | 5.2.3 (j) |
| Valve stem seriously damaged or misaligned | Major — fail | 5.2.3 (j) |
All four wheels are represented about equally, with the rear slightly ahead. There is no kerb side or driven-axle pattern here, which is what you would expect from a part that fails from age and not from use.
| Position written by the tester | Share of all instances |
|---|---|
| Offside rear | 23% |
| Nearside rear | 22% |
| Offside front | 17% |
| Nearside front | 17% |
| Rear | 7% |
| Front | 7% |
From 463,672 recorded instances. Testers can add their own note after the standard wording. The most common on this advisory: “perished” (18,164), “cracking” (6,019), “perishing” (5,711), “both” (5,017), “both sides” (2,630), “deteriorated” (2,163), “slightly perished” (1,874), “cracked” (1,747).
What it costs
| Job | Price fitted | Notes |
|---|---|---|
| New tyre, fitted, including a new valve | £70–£100 | The usual way a valve gets replaced |
A rubber valve is one of the cheapest parts on the car. The cost of replacing one by itself is nearly all labour, because the tyre has to come off the rim and be rebalanced, and we do not publish a range for that because fitters vary so much. If the tyres are due within the year, do both at once. Pressure-sensor valves cost more to service. Other prices are on the repair costs index.
Can I still drive with this advisory?
Check that tyre’s pressure weekly until it is fixed, and have it done within a month or two, sooner if you drive on motorways. A valve that is visibly cracked all the way round its base should be replaced before any long fast journey.
Enter your reg to see the full MOT record. Tyre advisories on the same wheel in earlier years will tell you whether the valve and the tyre are the same age.
Which cars get this advisory most?
At 0.9 per 1,000 tests this is rare on every model. The ones where it is least rare fall into two clear groups.
| Model | Per 1,000 tests | Vs all cars | Tests |
|---|---|---|---|
| Citroen Relay | 3 | 3.1× | 662,399 |
| Porsche Boxster | 2 | 2.5× | 309,679 |
| Mazda MX-5 | 2 | 2.5× | 962,840 |
| Saab 9-3 | 2 | 2.2× | 589,429 |
| Vauxhall Movano | 2 | 2.1× | 544,309 |
| MINI (all models) | 2 | 2.1× | 3,449,907 |
| Peugeot Boxer | 2 | 2.1× | 1,050,128 |
| Peugeot 206 | 2 | 2.0× | 1,061,894 |
| Smart Fortwo | 2 | 2.0× | 525,809 |
| Fiat Doblo | 2 | 2.0× | 537,931 |
Model families are grouped by the first word of the DVSA model name, so “Transit” covers every Transit variant. Only models with at least 60,000 tests are ranked.
The first is cars that cover few miles. The Porsche Boxster and Mazda MX-5 are roadsters that often stand through the winter, and the Smart Fortwo is a city car that rarely goes far. Their rubber wears out by the calendar, not the mileage.
The second is large vans: the Citroen Relay at 3.1 times the average, the Vauxhall Movano, Peugeot Boxer and Fiat Doblo. Vans run high tyre pressures and heavy loads, and their valves are worked harder on every mile.
What to do next
- Bend each valve gently and look at its base. Fine cracks that open as you bend it mean it is perished. Do all four, not just the one on the certificate.
- Read the tyre date codes. Four digits after DOT on the sidewall, week then year. Old valves usually mean old tyres.
- Combine it with tyres if they are due. A new valve comes with each new tyre at no extra charge almost everywhere.
- Insist on new valves with new tyres. It is standard practice. If a quote does not mention them, ask.
Tyre valve stem advisory FAQ
What does valve stem slightly damaged mean on an MOT?
The rubber tyre valve on one wheel is cracked, perished or slightly bent. It still holds air, so it is an advisory and the car passes.
Is a damaged valve stem dangerous?
It can become so. A perished rubber valve can split at its base and let the tyre down quickly, which is most likely at speed. At the advisory stage it is holding, but it should be replaced soon.
Will it fail the next MOT?
According to DVSA MOT data analysed by PriceMyRepair, 3.5% of 184,267 such advisories failed on a valve at the next test, and 10.3% failed on a tyre defect of some kind. Perished valves and ageing tyres usually go together.
How much does it cost to replace a tyre valve?
The valve costs very little. The work is removing, refitting and balancing the tyre. A new valve is normally included with a new tyre, which costs £70–£100 fitted. These are estimates and final quotes come from tyre fitters and garages.
Can I replace a valve stem without replacing the tyre?
Yes. The tyre is taken off the rim, a new valve is pulled through, and the tyre is refitted and balanced. It makes most sense when the tyres still have plenty of life left.
What if my car has tyre pressure sensors?
Sensor valves usually have metal stems and are serviced with a new seal, core and cap when tyres are changed. If the stem itself is damaged or corroded the sensor may need replacing, which costs more.
How these figures were calculated. According to DVSA MOT data analysed by PriceMyRepair, from the DVSA anonymised MOT test results (Open Government Licence v3.0): 350,943,111 tests. This advisory was recorded 463,672 times; 184,267 of those were followed to the same vehicle’s next test between 180 and 730 days later. “Fails on the same part” means a failure at that next test under the same defect code and naming the same component, on either side of the vehicle. Testers do not always name a component the same way twice, so the figure is a floor. Method and how to cite.