Your Top 3 Questions About Exhaust MOTs, Answered

The MOT test includes strict checks on your exhaust system. Here’s what you need to know:

1. How loud is too loud?
The current legal noise limit for vehicles is 72 decibels measured from 7.5 metres away. This will drop to 68 decibels but only for new vehicles type-approved after July 2026. This new lower level is for new vehicle types, existing vehicles on the road won't be automatically affected by the new lower limit. 

The tester will check that the exhaust noise is not “appreciably louder” than a standard system. A subtle, deeper tone from a quality aftermarket back box is usually fine. An excessively loud, raspy, or blown system will likely fail - a rough threshold/unofficial guideline is noise levels pushing above 82 for a vehicle under load during its MOT test.   

2. What about emissions?
This is crucial. Your exhaust must direct gases away from the car and the catalytic converter must be present and working correctly. Any leaks or missing components will cause an instant fail.

3. Will my aftermarket exhaust pass?
Yes, absolutely. There’s no rule against aftermarket parts. The system simply must be secure, free from major leaks, not excessively noisy, and comply with emissions regulations. Whether professional or DIY, correct installation is key. The best way to ensure a pass is with a pre-MOT exhaust check.

Browse our EC-approved, E-marked exhausts—tested and approved for road use and engineered to both sound great and comply with UK noise limits.   

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