Mopar Muscle Association UK

Car failed MOT because the exhaust is blowing but passed all of the emissions.

So why would it fail simply on 'blowing' when some of our cars sound like thunder on steroids????

That's harsh, you've taken that to the wrong testing station

Because the MOT regs state the exhaust system can’t have any leaks, how loud it is is a separate issue.

So due to the leak, the exhaust exits 12 inches before it exits anyway, passes the emissions test but fails the MOT. Am I missing something here?

Yes, it passed the emission test but failed the exhaust not leaking test, 2 separate issues not one and the same. The exhaust analizer only checks the CO content of what's coming out of the tailpipe, if some of the exhaust output is exiting somewhere it shouldn't then the analizer can't read that.

I don't know for sure, but I would have thought its because of the chance of fumes being introduced into the car ?

yes i think the first exhaust gas "exit" has to be behind the last opening window or some such

so if you have a blow under the floor where fumes can get in via the shifter hole or via the open door or side windows they can fail you.

which is one of the reasons my daft trumpet side pipe is blocked off, (the other is it sounds like a lunatic with a trombone). it exits in front of the rear wheel and i have opening window above.

you can also get caught if the tail pipe is too short on an estate car. in theory needs to be beyond the opening for the boot or it used to modern cars don't seem to comply but sealing and smooth bumpers with integrated tail pipes maybe count for something

i think its down to the testers interpretation. he doesn't want you all rosy cheeked, bad head, and dead.

Dave999 wrote: Thu Jul 25, 19 10:29 am yes i think the first exhaust gas "exit" has to be behind the last opening window or some such

I used to believe the same Dave until i was at the classic car show in 2017.
They had the new TVR Griffith and the exhaust exits just behind the front wheel.

Not sure what the law is:

Quote from MOT inspection manual. Section 6.1.2 Exhaust system
You must check the exhaust system of all vehicles with an internal combustion engine, including hybrid vehicles.

You need to assess the overall security of the exhaust system. One or more missing or defective exhaust mountings does not necessarily make the exhaust insecure.

For exhaust noise assessment, see Section 8.1.1.

For assessment of catalytic converters and diesel particulate filters, see Section 8.2.

Defect
Exhaust system has a major leak or is insecure. Major
Exhaust fumes entering cabin. Major
Causing a danger to health of persons on board. Dangerous

There is no failure just because the exhaust does not clear the body of the vehicle. Exhaust fumes must enter the passenger cabin to fail.
Back to Jems failure the failure would be a major leak not just blowing. On vehicles that get the 4 gas emissions test (generally post 01/08/1992) if the exhaust leak is bad enough to fail usually the lambda reading would be outside limits .
Maybe the tester was a bit keen.