An oil leak advisory means a leak was seen but it is not excessive. A fluid leaking excessively is a major defect and a continuous leak that is a serious road risk is dangerous. A leak forming a pool over 75mm across within 5 minutes is a fail.
Checked 23 October 2026 against the DVSA MOT inspection manual
- Excessive leak: Major defect
- Continuous, serious risk: Dangerous defect
- Fail test: Pool over 75mm within 5 minutes
- Not a fail: Coolant, screen wash, SCR fluid
What this advisory means
An advisory is recorded when an item is not deteriorated enough to justify a fail, so the presenter is informed of the issue. Advisories do not cause a fail and are recorded in the MOT history. An oil leak note therefore means the tester has seen a leak but judged it below the threshold for a defect. It is information for the presenter rather than a rejection of the vehicle.
The tester makes the check with the engine idling. A fluid leaking excessively and likely to harm the environment or pose a safety risk is a major defect under DVSA manual 8.4.1 a i. Leaking continuously and a serious risk to road safety is dangerous under 8.4.1 a ii. A leak that forms a pool over 75mm across within 5 minutes is a fail. Coolant, screen wash and SCR fluid leaks are not reasons to fail.
Where a leak is present but does not meet those thresholds, an advisory is the correct outcome. The note records what was observed without affecting the test result. Because it is stored in the MOT history, the leak is documented for future reference. The distinction rests on the rate of leakage and the risk it presents, not simply on the presence of oil.
When it becomes an MOT fail
A leak stops being advisory when it is excessive and likely to harm the environment or pose a safety risk. Under DVSA manual 8.4.1 a i, that condition is recorded as a major defect and the vehicle fails. The inspection is made with the engine idling.
Where fluid leaks continuously and creates a serious risk to road safety, the defect is classed as dangerous under 8.4.1 a ii. The practical marker used in the bay is a pool measuring over 75mm across that forms within 5 minutes. A pool of that size within that time is a fail, whether recorded as major or dangerous according to the risk.
The rule applies to oil and similar fluids, not to every liquid under the bonnet. Coolant, screen wash and SCR fluid leaks are not reasons to fail an MOT. Only the excessive or continuous loss covered by 8.4.1 a i and 8.4.1 a ii moves the advisory into a fail, and the 75mm pool within 5 minutes is the condition that confirms it.
| DVSA manual ref | Defect | Result |
|---|---|---|
| 8.4.1 (a)(i) | Fluid leaking excessively, likely to harm environment or safety | Major |
| 8.4.1 (a)(ii) | Fluid leaking continuously, serious road safety risk | Dangerous |
Source: DVSA manual section 8: nuisance, checked 23 October 2026.
Frequently asked questions
What is an MOT advisory?
An advisory is used when an item is not deteriorated enough to justify a fail, to inform the presenter. Advisories do not cause a fail and are recorded in the MOT history.
When does an oil leak become a major defect?
A fluid leaking excessively and likely to harm the environment or pose a safety risk is a major defect under DVSA manual 8.4.1 a i. This causes a fail.
When is an oil leak classed as dangerous?
A fluid leaking continuously and posing a serious risk to road safety is a dangerous defect under DVSA manual 8.4.1 a ii. This causes a fail.
How is the 75mm pool rule applied?
The check is made with the engine idling. A leak that forms a pool over 75mm across within 5 minutes is a fail.
Do coolant, screen wash or SCR fluid leaks cause a fail?
No. Coolant, screen wash and SCR fluid leaks are not reasons to fail under the DVSA manual.
Part of the MOT guide series
MOT check: the full guide › MOT advisories
‹ MOT Advisory: Exhaust: What the Note MeansMOT Advisory: Suspension Arm Bush Worn: What It Means ›
