Is it the cat.?

[vivandorron]

Last September we took our 7yr old Seat Leon (1.6) for annual service and it proved necessary to have sections of the exhaust replaced and they included the catalytic converter.

Everything seemed o.k. but then a metalic sound of vibration developed on start-up and appeared to be coming from the exhaust pipe. We took the car back for examination and all exhaust brackets were checked and one was re-tightened. However the problem still remains.

It is the case that start-up on very cold days produces a considerable sound of vibration which soon disappears when the car is driven off from its standing position. Occasionally the sound will return for a few seconds when moving-off in traffic with 1st gear engaged.

Accordingly we ask " Could there be a vibration within the Cat and is it something which can be ignored ?."

Viv & Ron.

[rinkins]

Sorry guys, for a moment I did wonder why you were asking about a cat in the motoring section. I got a bit worried when I read the last bit first.

[benny3008]

Same here, i thought you were asking if one of your long passed pets was actually living in your exhaust system!

[Toureman]

The rattle could be caused by the Catalytic converter braking down inside, it can happen over a length of time.

[vivandorron]

Hi rinkins and benny3008, I can fully understand your lines of thought about the beastly nature of my question. lol..

I thought Toureman that a new cat had been fitted, but it is possible that was not so. The only thing I know is that a mounting bracket for the cat was identified as being broken when the car was M.O.Td and it needed two parts to put matters right.(VK 7023 & VK8075) Pehaps wrongly I have thought that they included a replacement of the actual Cat which is playing-up.

As it is possible that the Cat now needs to be replaced, I guess I.ll have to return to the car's repairers. I can't tell you who they are for fear of being guilty of personally advertising on AB.....anyway I trust their workmanship and they do Fit Quickly.

Thaks for responses .....Ron

[Panic Button]

.... or it might be a heat shield, between exhaust and the car floor, rattling.

[mr_g_uk]

Yes, most probably 2 of the above options - loose heatshield or broken substrate within the cat shell.

If it's the heatshield I'd be more tempted to think you'd hear it more often than just in first gear but it could still be. Have that checked first - it's the cheapest of the 2 fixes!

The substrate breaking up, however, is more likely to me. The substrate in ceramic cats is very brittle and if it becomes damaged in the slightest can cause a small chip of it (or a foreign object) to blow around inside chipping bits off. Eventually the substrate will become loose and ends up working itself into a ball shape and can cause a blockage in your exhaust system leading to more serious damage.

Hope this helps.

[vivandorron]

Hi mr_g_uk.

I have not overlooked the views of S_King and Panic Button for which I thank them for having reponded on this matter. However I am inclined to think that both yourself and Toureman are thinking along similar lines to myself.

It looks as if I shall have to return to KF with the possibility of having to get a new cat to get the sort of purr to which I had been accustomed.

Incidentally, if anyone is wondering why I do not go to a Seat dealership for sevicing etc......The answer is that there is no longer one in my area.

Best wishes.....Ron

[vivandorron]

Good afternoon motoring mates,

We have arranged to take our car for examination on Friday and will post a note of the oucome.

Thanks all.......Viv & Ron.

[vivandorron]

Took the beast for examination and was assured that the Cat was in good physical condition. I was pleased because it was a new replacement, last September, and I had started to be a little bothered about the possibility of a 'fur' ball in the Cat causing a serious problem.

I was welcomed into the operating theatre to see for myself that a bracket had severed in the middle section of the exhast pipework. The 'Doctor' was of the opinion that it would be somewhat extravagent to replace pipework for the sake of a bonded bracket and suggested that all could be put right with a Jubilee clip. I agreed, and as an interim measure the pipe has been prevented from vibrating by being secured in place with some strong wire. ( a welding rod until a suitable Jubilee clip is obtained.)

Thanks all for having expressed your views on matters. Your observations gave me sufficient knowledge to know what technicians should examine and also, from your responses, I was confident enough to question Diagnosticians on the necessary operation to put the beast back into good health.

Thanks again and best wishes..........Ron.