135is owners

[one&only35is]

so ive had my car for about two months now from bob smith bmw and i can't seem to figure out whats causing the rattle in my exhaust. it only happens when the car is cold around 1.5-1.7k rpm. its been like this for a month or so now.. any ideas? and yes i know i can take my car in for service, but i rather not knowing how pacific bmw loves new 1 series'

[tuj]

Does the 135is have the same exhaust as the Dinan 'performance' exhaust?

[Sleeps]

Originally Posted by one&only35is

so ive had my car for about two months now from bob smith bmw and i can't seem to figure out whats causing the rattle in my exhaust. it only happens when the car is cold around 1.5-1.7k rpm. its been like this for a month or so now.. any ideas? and yes i know i can take my car in for service, but i rather not knowing how pacific bmw loves new 1 series'

I have not heard any rattle from my exhaust so far. Is your car a MT or DCT? I have a MT and sometimes i can hear my clutch chatter when idol and in neutral.

[alexmtl_135i]

Originally Posted by tuj

Does the 135is have the same exhaust as the Dinan 'performance' exhaust?

Nope, they have the BMW Performance exhaust.

OP, can you post a video ? My PE makes a different sound when the engine is cold as well, but nothing that I dislike

[roxig226]

New member here. Purchased my 135is coupe w/DCT in September. I'll tell you what my experience has been and what I think the problem is.

On cold start everything sounds fine. Start driving and every time I hit a slight bump in the road there is a (maybe multiple) "clunk" that sounds like it's coming from underneath the passenger seat. After about 5 minutes the problem goes away except when I hit a large bump when decelerating with no throttle.

After the car has sat for maybe an hour and started there is a rattle when reversing and then the same "clunking" sounds when hitting bumps in the road. Once again, it stops after about 5 minutes.

After several trips under the vehicle I noticed one of the exhaust pipes was touching a "dished" steel plate in the center of the vehicle. The two exhaust tubes cross over this plate just before the "Y" pipe. I think that after the exhaust heats up and expands it is no longer resting on the plate, until it cools off again.

To see if that was the case I placed a rubber exhaust hanger between the plate and the tube that was touching it. I cold started the car and took several short trips. Silence! No more clunking sound. That seemed to eliminate the problem. I didn't leave the rubber piece there for fear it would melt and/or possibly ignite after the exhaust reached a higher temperature.

I assume the exhaust system can be adjusted to eliminate the problem. I will eventually take it back to the dealer now that I have identified the problem. About a month after I got the car it was back at the dealer but they "could not duplicate" the problem. And the salesman told me all the is's make the noise I described. Right.

Maybe this can help you. I love the car except for this issue.

[mb135is]

I have a rattle at the RPM the OP mentioned. No clunks, just an occasional rattle/resonance just below 2k rpm. Sounds like a heat shield but not that blatant.