Knocking Sound

[Aries326]

I've recently noticed a knocking sound coming from my Z4. I've never noticed it before but I wouldn't call myself a real car guy like some of you fellas who wrench on your own vehicles or have been around cars forever.

It's unlike the lifter tick which is higher pitched. My car used to have it until the lifters were replaced a few months ago. This knock is lower pitched and happens all the time without fail after I've driven my car. The sound disappears when I step on the clutch. My brother thinks there is a problem with the "throw out bearing". I have no clue. He's the mechanic but he works on Audis.

Is this knocking normal? Thanks in advance for the advice.

[seank]

If your brother is a mechanic, I would listen to him. Most noises, mechanics, and systems are the same from car to car.

[Aries326]

I've been searching YouTube and the web about this knocking sound. I'm convinced it is the TOB. My appointment with the dealership is July 3. I hope it is covered under warranty.

[Aries326]

So, BMW replaced the clutch, TOB and the knocking is gone. However, now I hear a rattling which goes away when I step on the clutch. That rattling wasn't there when I first had the car repaired. Is that rattling sound normal??? Should I bring the car back to have it checked out? Thanks.

[dubsesd]

yes. i would

[Aries326]

Originally Posted by dubsesd

yes. i would

Does your car have a rattling sound when you step on the clutch?

[gtMc]

Originally Posted by Aries326

Does your car have a rattling sound when you step on the clutch?

I have just noticed in the past 2-3 weeks, I am getting a strange intermittent rattling/clanking sound too when I step on the clutch. Its doesnt always happen and i cant replicate it on demand. But when it does it, it sounds like either a bark chip rattling thru a fan blade, or almost like a nail in a coffee can (no not vanos bolt sound though). It happens when I depress the clutch pedal and then it just starts up for a few seconds. and I can feel a bit of vibration in the foot pedal and in the shift knob that coincides with the rattle.

took it to my indy, and of course due to murphys law, the sound did not occur when he had the car in his possesion. but he too thought it could be the TOB.

uuuuuugh......

[Aries326]

Yeah, that's it. It is a rattling sound but mine goes away when I step on the clutch. I think I stated it incorrectly in my other follow up post when I said it is there when I step on the clutch. I can definitely replicate the sound. All I need to do is go on a half hour drive. I pull in and I hear the rattling. I step on the clutch and it goes away. You are right when you say you can feel more rattling as you push the clutch down. Definitely the sound is new and wasn't there when I first got the clutch replaced.

I'm bringing it back to the dealer next week.

[txz4]

if its only when you step on the clutch, specifically easy to replicate in first gear in a parking lot and quickly clutching in, its just normal clutch chatter for this car. If you hear rattling when the clutch is out, something is not as it should be.

[Aries326]

I definitely hear the chatter when the clutch is out. It's not there when I first turn on the car. When I get to my destination, park, put the car in neutral and engage the e-brake, the chatter is definitely there. I step on the clutch, sound goes away. Brought it to the dealer and he said it was normal play coming from the transmission. The transmission in my Honda Civic never had any chatter. I plan on taking the car to an independent mechanic to diagnose then I'm taking it back to the dealer if indeed it is abnormal.