Rattling from under car

[Steve-O]

I have a 1991 190E and When the car Warms up to around 80 Deg and I press the accelerator to rev it, you can hear a Rattle / Vibration noise coming from Catalyctic converter area.

Am I right in thinking that when a catalyctic converted dies it can crumble up and cause these vibration / rattling noises?

Thanks

 

[matrix]

Make sure that you did not break down your cat. I am living the same problem with my '92 E200. Even when it is cold, by pushing the accelerator, i can hear rattling down there...

 

[Blobcat]

Yes your cat could very well be rattling around. Aftermarket ones are available, however there are quite a few posts on here that they are either a lot noisier than original fitment or do not work at all.

 

[Parrot of Doom]

1991 - thats before the legislation required cats, isn't it?

In which case, if it is the cat, I'd just replace it with a normal section of exhaust, much cheaper.

 

[Steve-O]

yea thats what Im going to do... Will just chop it out and weld some straight pipe inplace of it.

I think its 1993 onwards you require a Cat (Or if you remove the Cat and can pass the emissions test you dont require one)

 

[d4hwt]

I had a similar problem on my W210. It turned out to be the bracket which is welded onto the exhaust had failed at the weld and was only noticable at certain revs. I found it was worse when reversing, any case i got it welded back up and its been fine since. Not sure if its the same on a 190 but maybe worth checking it should be roughly in the middle of the car. It was a "tinny " noise. I've had a cat go on an old mondeo before and the noise was more prominent , it had come loose inside and was rattling around, i was told to replace it asap incase it became lodged and blocked the exhaust by a mechanic...Eventually got one off e-bay for a lot less than the dealership...

 

[tom7035]

Probably is the heat-shield over the top of the cat.

 

[matrix]

Dont do it

yea thats what Im going to do... Will just chop it out and weld some straight pipe inplace of it.

I think its 1993 onwards you require a Cat (Or if you remove the Cat and can pass the emissions test you dont require one)

I think you shoud ensure that it is safe for other parts. I was told in the garage that it affects the engine functions. Somebody in the forum, said it badly affects cylinders....

 

[flyingtech55]

Go ahead!

Hi Steve-O

I can assure you that its quite OK to remove the 'cat on your '91 190E. I've done just that on mine and its run perfectly for two years and it passes it's MOT. The 'cat on these cars only improves the emissions by 1/2% (that's right half of one per cent). However, you must retain the Lamda sensor in the same position. You will not do any damage to the rest of the engine. I don't know why garages tell these porkies, is it just ignorance or is it deliberate lies. Obviously if your engine is marginal on emissions already the removal may just bump it over into fail. I can't advise on that aspect. However, I would suggest that you renew your Lamda sensor with a new one (a genuine Merc. one). The Lamda sensors really need renewing at about 100,000 miles. It's often tired Lamda sensors which cause the initial failure of the 'cat due to the engine running rich. Its very easy to change, the plug is under the driver's seat; use a decent spanner though.

HTH

Gliderman

 

[MW]

My 1992 230E is the same. At the last MOT the mechanic took me underneath to look at the heat shield which is slightly loose. Being stainless steel, it has a very thin metallic sound. A spot wield would probably fix it. I also have a cracked exhaust bracket which is probably also contributing to the noise.

 

[Steve-O]

I think you shoud ensure that it is safe for other parts. I was told in the garage that it affects the engine functions.

I think the garage is probably just trying to con you out of money by saying that as you can purchase De Cat pipes etc and cars before 1993 didnt even have one fitted (it was optional to have one)

Think I will just get it cut out on Saturday after work or something , will only be a 10 min job I would think (just cut cat out, slide new pipe over, weld pipe )

 

[Blobcat]

I think the garage is probably just trying to con you out of money by saying that as you can purchase De Cat pipes etc and cars before 1993 didnt even have one fitted (it was optional to have one)

Think I will just get it cut out on Saturday after work or something , will only be a 10 min job I would think (just cut cat out, slide new pipe over, weld pipe )

Pls take care with the electrics, I had my rear exhaust bracket welded recently, no probs but welder put a spike/surge arrestor across the +Ve & -Ve terminals. Best if you can weld it off the car.

 

[matrix]

Yeah, Bloabcat is right, when I had my rear exhaust pipe repaired, they did it off the car. First safety, then the cut line is to be done from the upside of the pipe, not from down. Otherwise, it may corrupt out in a short time (rust problem)

 

[Steve-O]

Should be fine, they are always welding so they will know what to do etc. Was going to get it done tomorrow but its the England game so they wont realy want to stay back after work to do it I wouldnt have thought.