Seat Arona failed first MOT

tedted

yes i read your link did you check

MOT inspection manual: cars and passenger vehicles

Barkin

ROY47 said:

The emission restrictions for diesel engines must not be exceeded. The emission restrictions are as follows:

• CO limit of 0.50 gm/km
• NOx limit of 0.25 gm/km
• A combined HC and NOx limit of 0.30 gm/km
• PM limit of 0.025 gm/km.

Where did that come from?

'cause it looks to me like the requirements for an engine to be manufacturer 'certified' as Euro4 compliant... 

ROY47

Since the EU Roadworthiness Package of May 2018, it has become a lot easier for diesel cars to fail their MOT. The level of nitrogen oxide (NOx) and carbon monoxide (CO) that diesel engines produce can have a detrimental impact on the environment and, consequently, the EU have put restrictions on the level of diesel emissions that your car can release.

The UK have mirrored this so currently, to pass your MOT, your car's MOT emissions have to fit specific criteria. Our tips will help you reduce your diesel car's NOx and CO emissions, not only saving you hundreds of pounds on a new vehicle, but also helping keep our planet safer for longer.

https://www.ptagarages.co.uk/blog/how-to-lower-diesel-emissions-for-mot/142

MOT inspection manual: cars and passenger vehicles

 yes I looked there as well

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<snip>

• The emission restrictions for diesel engines must not be exceeded. The emission restrictions are as follows:
  • CO limit of 0.50 gm/km
  • NOx limit of 0.25 gm/km
  • A combined HC and NOx limit of 0.30 gm/km
  • PM limit of 0.025 gm/km.
  
  
  I know it's correct because my Fiesta diesel was close to failing because of emissions . I was told after to drive it on a damn good run on motorway
  

Look at the units, per km, an MOT station is not going to be able to measure those.

These are actually the Euro 4 specifications, that the manufacturer had to manufacture (if they didn't get found out..... cough... VW) the car to when it was made. They are never checked again outside of a laboratory.

(That nice man Mr Khan doesn't like Euro 4, he wants Euro 6 if you go near Londinium btw).

The MOT unit for smoke opacity is per metre, which is not to do with distance, but is a calculated function of particle size, number in a fixed volume and the absorption co-efficient of the particle (which ought to be constant if it is just soot, but may vary with water & HC concentration)

facade

ROY47 said:

 I'm saying my answer is correct  did you read the link I posted ?

https://www.driving.co.uk/car-clinic/guide-new-mot-test-changes-including-tougher-diesel-emissions-limits/

I read it, they are writing about smoke opacity, nowhere do they mention the figures you quote

The confusion is because some testers, newspapers and even DVLA refer to smoke opacity as just "emissions", when really the deadly emissions from diesels aren't even measured, we petrol drivers are punished for making carbon monoxide or releasing hydrocarbons, diesels can do what they like as long as they don't make smoke.

daveyjp

cullet said:

Upon further investigation my mechanic he discovered that at the previous service the wrong engine oil was used pushing the emissions sky high.Following an oil change the car car past the retest 👍

Very hard to believe.  I suspect the failure was with the emissions testing equipment and it gave a false flag failure, or the emissions test was done incorrectly.