Over the last few weeks I have noticed a rattle coming from the nearside,when car on tickover or low revs in traffic.
As had a few spare hours this morning decided to investigate.Because it was too cold to start crawling about under car,decided to go to nearby exhaust/tyre shop as they could get car in air for me to look at.
It appears that the "brick" inside the nearside cat has worked loose and is that which is causing the rattle.
They very kindly offered to fit a new 1 for £180=00 which did include the gasket ,but said if lamba sensor snaps when removing that will be an additional £80 ish...seems like a good business to be in this time of year.
Question is ,due to MOT coming up in mid january,will the loose cat insides cause the emmissions to be too high with a subsequent failure or is it no more than a rattle which whilst annoying,would annoy me a lot more spending £200 + this time of year.
Would it also be better to buy a new cat,or is this a a case for a second hand unit .

When car was in air we gave the nearside cat a good thump and it was certainly a rattle..nothing from offside.....couldnt see any heatshield with clips on either side,so does seem plausable that something is loose inside of it...and it is the original unit circa 1998 so it hasn,t done bad .
Thanks for picture Entwood.

Not sure if this is related to the current issues I have with the nearside cat,but several weeks ago I had a major missfire which was eventually traced to the 3 plugs on the nearside bank being almost underwater.These have now been replaced and car was running fine up to the "rattling I have from the nearside cat...could this have been caused by that side of the engine missfiring and destroying the cat.