[Yossi123]

Recently I noticed that the engine vibrates noticeably when idling with revs below 1000 rpm. Vibration doesn't transfer to cabin so I haven't noticed it until now.

Should it idle super smooth or is this normal with this engine?

I had no issues with it whatsoever for the last 15k miles, it runs just great. But now when I noticed the vibrations I wonder if I should report it to the dealer?

[JFray23]

I'm guessing it's normal. My turbo 4's in both my X1 and X3 previously vibrated a lot, especially the X1. I honestly believe it's a characteristic of BMW turbo 4's.

[Yossi123]

That's reassuring, as sometimes I can just feel the very slight vibration on drivers seat headrest. Very subtle, but it's there.

[VipinLJ]

Yea. Characteristic of BMW I4s. They definitely do not idle smooth. Audi I4s idle very smooth in comparison.

[stuntman.josh]

Crazy enough my car started doing the same thing 10 minutes ago

[Info@mad-us.com]

The n20's wore their engine mounts out fairly quickly not sure if the b48's have that issue. Worn plugs can also cause a bad idle.

[thakid22]

Originally Posted by Yossi123

Recently I noticed that the engine vibrates noticeably when idling with revs below 1000 rpm. Vibration doesn't transfer to cabin so I haven't noticed it until now.

Should it idle super smooth or is this normal with this engine?

I had no issues with it whatsoever for the last 15k miles, it runs just great. But now when I noticed the vibrations I wonder if I should report it to the dealer?

I have paid special attention to the 330i B48 loaners I last had.
Those engines idled silky smooth and were damn near silent at idle (after warmed up and with the windows closed).

There was a distinct lack of vibration and sound at idle in the 330i and X1 2.0 that I drove.
In fact, it was startling because they idled smoother and with less vibration than my new M340i. However, the m340i models have a more aggressive exhaust which causes a bit of extra sound and feel to be transmitted into the interior. So that is somewhat understandable.

If you feel your 330 is not appropriately silky, you need to go to the dealer and test another new one and evaluate the idle on that car in comparison to yours. If the disparity is great enough, book a service department visit and then be prepared to show them the difference between your car and their new car when they say yours is "normal." Also be able to replicate, at will, the conditions when your idle is bad. They'll need to experience it to fix it.

Having driven many BMW over the last 10 years, I can say without a doubt that idle quality varies quite a bit, even amongst identical models. Most people won't notice, but if you are keen to such things it really stands out. As the vehicles age, I've found Bmw idle quality can decrease as well. Strict maintenance and good quality fuel seem to slow or altogether prevent this decline. However, you still have the variability that is seen in new models fresh off the lot.

Go compare your car to another on the lot and proceed from there.

[g20beam]

It used to be like that on my car but something I did made it disappear. I am 90% sure it is the spark plugs because ever since I've had them replaced, my idle has been so smooth to the point where there is hardly any vibrations at all, never have I experienced idle vibrations ever since.

Get new spark plugs, get them installed professionally at a shop and ask them to gap each and every one of them and ensure it is the same.