Leaky exhaust....

[Brian Griffin]

Car (03 1.4 Megane) failed its test today..the guy showed me the report and said that the meganes have problems with leaking around the welds...anyone had/heard of this before...????

[davelowe]

In a word, no, I haven't heard about it before, but that isn't to say nobody else has.

Have you inspected the exhaust system yourself?

My 03 plate original exhaust has never been a problem, but then we don't have the same car. Repairs are possible on welded segments as are on straight sections.

That said, if it is badly corroded, I would have the MOT guy show me exactly what the problem is while the car is on a ramp so I could see for myself (and poke it). I only say this because I had a 'conversation' with the MOT guy at my local test centre when my mum took her car in and I went to collect it. He failed it for various things including minimum brake disc thicknesses. A swift demonstration with a micrometer and reference to the handbook (measured 17.2mm when the minimum is 16.0) changed his mind. This kind of thing happens a lot with cars. It's called a rip off.

Obviously if it is blowing (quick test: start engine, put rag over exhaust pipe, listen for wheezing noises and lack of back pressure) and / or sounds loud, you will simply have to get it fixed and there was a problem after all.

You don't have to rely on the report. Legally you are allowed to 'watch the MOT from a designated place, but not interfere with the engineer'. I always do. For one, it keeps their minds on the job, and a pre-MOT check that you can do yourself for nearly all of it bar the emissions is a good plan too.

[Brian Griffin]

Just crawled under for a look...right enough theres a pin hole in the weld in the mid box and a small leak on the rear box both on the lowest part..i'm guessin its as a result of water sitting there...would these leaks affect the reading ?i thought as they were after the cat and sensor it would'nt..am i wrong..

[davelowe]

If the HC and CO ratings have been printed off and are within the limits (you should have /get a copy) then it can't fail on the emissions test.

Check this out:

https://www.motuk.co.uk/manual_710.htm

Specifically reasons for failure:

1.
a. A part of the system missing or excessively deteriorated

2.
a. A major leak of exhaust gases from any part of the system

Note: A minor exhaust leak from, for example, a connection joint or a pin hole, is not a Reason for Rejection

[chevin]

Brian,

Have Nov 2003 Dynamique - just before both 2008 and 2009 MoT's I've checked the exhaust to note rust/holes around the back box seams - lower seam weld right at the rear - and the car is parked on a slight decline - so its the opposite to where you may think.

Solution: £ 5 tube of plastic paddding over the 2 years fixed it no problem.