Older Pre Cat Cars and MOT
Older Pre Cat Cars and MOT
Author
Discussion

as400

Original Poster:

158 posts

239 months

Thursday 28th August 2025
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Do older cars that never had a CAT fitted struggle with MOT emissions come MOT time?...or do they get given some form of special dispensation/leniency?


droopsnoot

14,519 posts

269 months

Thursday 28th August 2025
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It depends on the year. Up to somewhere around 1975, it's a check for visible smoke, my 1976 Vauxhall has to have an emissions test but it's less stringent than a later car.

Details here: https://www.gov.uk/guidance/mot-inspection-manual-...

Sebring440

3,172 posts

123 months

Thursday 28th August 2025
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FilH

1,121 posts

171 months

Thursday 28th August 2025
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Had my 1990 Sierra MOT'd yesterday.

He selected pre cat on the test machine, and probed the exhaust for an idle only emissions test.



Passed with CO of 2.31 % allowed 3.5
And HC of 88 ppm allowed 1200!

Post cat carshave a lot lower allowable amounts. CO is 0.3% or 0.5 % ones at idle the other 2000 something + rpms