[Zengineer]

Hello all - my car has had a rough startup sound since i've owned it, but the BMW tech says it's normal, which I could sort of believe. But lately, I hear a very distinct metallic "clunk" about 1 or 2 seconds after the engine has started. Sometimes I even hear 2 "clunks". It appears to be random, I cannot figure out the conditions in which it occurs.

Video below, you may have to turn up your volume to hear it. It happens around the 4 second mark, any ideas?

[CoffeeBean]

That is bizarre. Can you tell which area it's coming from? May have to get someone to start it for you a few times while you listen around the car to figure it out. The fan hitting the shroud maybe?

[Zengineer]

Originally Posted by Ross328i

That is bizarre. Can you tell which area it's coming from? May have to get someone to start it for you a few times while you listen around the car to figure it out. The fan hitting the shroud maybe?

It sounds more metallic than a fan/shroud contact. It sounds like its coming from under the car near where the transmission connects to the engine. It's tough because it doesn't do it regularly. That's a good idea though, I may have someone start it a few times with my head precariously beneath listening.

Whatever the pieces are that are hitting each other sound like metal and it sounds like they have some decent mass behind them. It's a pretty 'heavy' clunk.

When I get two successive clunks (after a single crank), it almost sounds like they're coming from different areas, but that could just be my mind playing tricks.

[benzo23]

That is really strange, I wouldn't even know where to begin guessing.

[Dylanize]

Originally Posted by Zengineer

Hello all - my car has had a rough startup sound since i've owned it, but the BMW tech says it's normal, which I could sort of believe. But lately, I hear a very distinct metallic "clunk" about 1 or 2 seconds after the engine has started. Sometimes I even hear 2 "clunks". It appears to be random, I cannot figure out the conditions in which it occurs.

Hey I think my car does the same thing, and I have been wondering what the hell it was?! Mine seems random to, but I have noticed it seems to do it more when I start my car on a slope. It almost seems like its the transmission slamming into a gear or something even though it's not.

Please keep this thread updated with anything you find, thanks and goodluck!

[Zengineer]

Originally Posted by Dylanize

Hey I think my car does the same thing, and I have been wondering what the hell it was?! Mine seems random to, but I have noticed it seems to do it more when I start my car on a slope. It almost seems like its the transmission slamming into a gear or something even though it's not.

Please keep this thread updated with anything you find, thanks and goodluck!

Thanks! Glad to know I'm not alone, haha. I am wondering now if it is an engine mounts, but it doesn't seem to come and go with revs, so I'm not sure. I'll update if I learn anything!

[Dylanize]

Originally Posted by Zengineer

Thanks! Glad to know I'm not alone, haha. I am wondering now if it is an engine mounts, but it doesn't seem to come and go with revs, so I'm not sure. I'll update if I learn anything!

Hmm, never thought about the mounts, but yeah if it only does starting then thats weird. I'm gonna try parking at different degree slopes forward and backward, see if I can come up with a replicable occurrence.

[vincent.s]

I get the clunk when i come to a stop and the car downshifts into 2nd i hear it more near the trans area as well

[Volasko]

How the eff is that sound normal..... damn dealers!

[MikeR1994]

If it were an engine mount the car would shake pretty significantly when the engine fires. How many miles do you have on your car?
The fact that you say it only happens upon startup makes me think it has something to do with the starter. It may be a possibility that it could be that the starter is not properly disengaging from the flywheel once it's job is done. There is something called starter run-on, which means that your starter stays on the flywheel after startup and you just hear a terrible winding noise from it. Obviously this isn't your problem, but I'll bet if it takes too long to pull away it could potentially catch the flywheel and make this sound. I don't know, I just have a hunch that it would be the starter.

[Dylanize]

Originally Posted by MikeR1994

If it were an engine mount the car would shake pretty significantly when the engine fires. How many miles do you have on your car?
The fact that you say it only happens upon startup makes me think it has something to do with the starter. It may be a possibility that it could be that the starter is not properly disengaging from the flywheel once it's job is done. There is something called starter run-on, which means that your starter stays on the flywheel after startup and you just hear a terrible winding noise from it. Obviously this isn't your problem, but I'll bet if it takes too long to pull away it could potentially catch the flywheel and make this sound. I don't know, I just have a hunch that it would be the starter.

Hmm, I just had my starter replaced, It did it before and now after.

[MikeR1994]

Originally Posted by Dylanize

Hmm, I just had my starter replaced, It did it before and now after.

Hm, that's doubtful then. It just really sounds like something is getting bound up then all at once slips off. It could also be some sort of gear lash? Can you feel it when it happens?

[Dylanize]

Originally Posted by MikeR1994

Hm, that's doubtful then. It just really sounds like something is getting bound up then all at once slips off. It could also be some sort of gear lash? Can you feel it when it happens?

I'd say I can feel it slightly, Like some one was knocking under the car.

[MikeR1994]

Originally Posted by Dylanize

I'd say I can feel it slightly, Like some one was knocking under the car.

I guess one way that you could tell if it is an engine mount is by having the hood up and watching for any movement that seems to correspond with the sound itself, and not the engine firing up. That could at least help you rule that out.

[Zengineer]

Originally Posted by MikeR1994

If it were an engine mount the car would shake pretty significantly when the engine fires. How many miles do you have on your car?
The fact that you say it only happens upon startup makes me think it has something to do with the starter. It may be a possibility that it could be that the starter is not properly disengaging from the flywheel once it's job is done. There is something called starter run-on, which means that your starter stays on the flywheel after startup and you just hear a terrible winding noise from it. Obviously this isn't your problem, but I'll bet if it takes too long to pull away it could potentially catch the flywheel and make this sound. I don't know, I just have a hunch that it would be the starter.

You are the second person to suggest a starter issue. It hasn't done it since I recorded that video... Do you know if this starter noise can be pretty sporadic?

I have 63,000 miles on the car. I do get some constant high frequency low amplitude vibrations through the steering wheel constantly (stopped, driving, in park, in neutral), not sure if the two are related at all.

Thank you very much for the detailed feedback!

[MikeR1994]

Originally Posted by Zengineer

You are the second person to suggest a starter issue. It hasn't done it since I recorded that video... Do you know if this starter noise can be pretty sporadic?

I have 63,000 miles on the car. I do get some constant high frequency low amplitude vibrations through the steering wheel constantly (stopped, driving, in park, in neutral), not sure if the two are related at all.

Thank you very much for the detailed feedback!

If it is a starter problem I don't see why it couldn't be intermittent. Have you talked to the dealership or a trusted independent about it? They may have fixed the same problem on another car before.

[Zengineer]

Originally Posted by MikeR1994

If it is a starter problem I don't see why it couldn't be intermittent. Have you talked to the dealership or a trusted independent about it? They may have fixed the same problem on another car before.

I sent the video to the dealership, their foreman wasn't too worried about it, but he didn't provide any suggestions either.

I have an appointment for 4/30 when they'll address the battery recall and look into this.

I'll report back if it anything specific comes out of it.

Thanks again for all the feedback!

[MikeR1994]

Originally Posted by Zengineer

I sent the video to the dealership, their foreman wasn't too worried about it, but he didn't provide any suggestions either.

I have an appointment for 4/30 when they'll address the battery recall and look into this.

I'll report back if it anything specific comes out of it.

Thanks again for all the feedback!

no problem, as a senior in high school this late in the year, trust me, I have plenty of time on my hands. I should be thanking you, haha.

[Three_thirty_I]

Very strange! What about the exhaust flap?

Also initially thought maybe the starter motor that was not disengaging quickly enough...

[Dylanize]

Any word OP?

[Three_thirty_I]

Originally Posted by Dylanize

Any word OP?

+1!

[Dylanize]

Originally Posted by Zengineer

I sent the video to the dealership, their foreman wasn't too worried about it, but he didn't provide any suggestions either.

I have an appointment for 4/30 when they'll address the battery recall and look into this.

I'll report back if it anything specific comes out of it.

Thanks again for all the feedback!

Did you hear anything???