Klack noise when engine stop and start

Havy · 09-21-2018, 10:59 AM

Hi guys,
I noticed a strange klack noise when the engine stops at a red light. Engine off and a second later a noticeable Klack comes from the tank area. When the engine starts again the same Klack noise. My mechanics keeps telling me it’s normal

maybe in his dream but not with a 150000€ car. Someone any idea what it could be.

BMWDriverX · 09-21-2018, 02:33 PM

Nothing good is going to come out of any car turning the engine on and off at every stop, turn off the feature.

Havy · 09-22-2018, 01:23 AM

The thing is that it makes that sound only when the start stop is active. If you switch off the car with the start button...no noise. And the funniest part is when you open the hood there is no Klack anymore

should I drive with an open hood.

Can somebody confirm this noise or is it only my car.

Whipple · 09-22-2018, 04:22 PM

Quote:

Originally Posted by Havy

The thing is that it makes that sound only when the start stop is active. If you switch off the car with the start button...no noise. And the funniest part is when you open the hood there is no Klack anymore

should I drive with an open hood.

Can somebody confirm this noise or is it only my car.

Is it the same klack when you shut the car off and engages park? I will try it on my car to see if this happens,I’m not sure I never tried it , it’s always engaged off .

Cincinnatus · 09-22-2018, 05:21 PM

Go ahead and ask my why the auto stop feature was the first thing I disabled. For the couple bucks per year of gas it saves, it's not worth the cost of a new starter motor. And where I'm concerned, there's questionable "eco-value" to it when yiu consider the "carbon footprint" consumed by production of a replacement starter.

Havy · 09-23-2018, 04:52 AM

Whipple,
When I turn the car off there is no klack. This is what I don’t understand. I would really appreciate if you could try it and report after. Maybe it is only a relais but for that it is too loud.
Cincinnatus it is not about saving some bucks, it’s about the noise it makes. It is a luxury car and it should not make any noises.

Monday I go back to BMW.

spikespiegel · 09-23-2018, 05:38 AM

the start stop starter is a separate starter motor and not the one you use when you press ignition on. Its designed for many, many start stop applications; and anything over 10 secs or so in idle, it does start saving fuel. I personally don't use it much unless i know i'm gonna be in really bad traffic.

Havy · 09-24-2018, 07:33 AM

So, I went to BMW and after the first glance it might be some small issue with the gearbox.

hmmm gear box and small issue....that doesn’t fit. Maybe they can fix it with a software update. Keep you posted.

Havy · 09-25-2018, 02:17 PM

So, here is an update. 2 mechanics and the customer service from BMW in Dingolfigen (the plant) told me that this noise is normal.

apparently it is a sort of locking device when the engine shut off at the red light and when the engine starts it will unlock and makes the same noise. I am not 100% convinced so I wrote a mail to the gear box manufacturer and asked him if this could be. This gear box (Getrag GS7-D36BG) is also used in the M5
Now, wait and see.

BMWDriverX · 09-25-2018, 02:19 PM

I turned this on today and there was no clack noise, just starts when i release the brake pedal.

Havy · 09-26-2018, 01:43 AM

And what about when your are braking and stop at a red light? Do you here a Klack right after the engine went off?

BMWDriverX · 09-26-2018, 04:00 PM

Quote:

Originally Posted by Havy

And what about when your are braking and stop at a red light? Do you here a Klack right after the engine went off?

Tried again today, no sound, just starts and stops and then starts again

Taheemr · 10-01-2018, 10:52 AM

That noise is normal, my current M6 does it, as did the one before, i have friend s with the M5 and m4, these do it too, dont worry

Havy · 10-01-2018, 01:25 PM

Yeah, thank you Taheemr

I went to a BMW branch office today and the chief mechanic who is responsible for M engines and gear boxes noticed it immediately.
„yes sir it is normal. This is the sound when the pressure valve open and closes to avoid that the gear box switch into P. All M vehicles with that gear box does it. Some little louder some more quiet but this is what you have to eat when you get this gear box.“

Taheemr · 10-02-2018, 07:22 AM

On a related note, when starting your car from cold when engaging gear, forward or reverse say, do you get a delayed reaction and then a thump as the gear engages, I would be interested to know

Havy · 10-11-2018, 11:59 AM

Hi Taheemr, either it is not cold enough or I don’t have that thump as you mentioned.

09-21-2018, 10:59 AM	#1
Havy Captain 303 Rep 709 Posts Drives: BMW X5 M50i Join Date: Sep 2018 Location: Europe iTrader: (0)	Klack noise when engine stop and start Hi guys, I noticed a strange klack noise when the engine stops at a red light. Engine off and a second later a noticeable Klack comes from the tank area. When the engine starts again the same Klack noise. My mechanics keeps telling me it’s normal maybe in his dream but not with a 150000€ car. Someone any idea what it could be.
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09-21-2018, 02:33 PM	#2
BMWDriverX Captain 366 Rep 804 Posts Drives: G12 750i X-Drive Join Date: Jul 2017 Location: CA iTrader: (1)	Nothing good is going to come out of any car turning the engine on and off at every stop, turn off the feature.
	Appreciate 2 BMWM5NYC496.00 gregmb19.50 Quote

09-22-2018, 01:23 AM	#3
Havy Captain 303 Rep 709 Posts Drives: BMW X5 M50i Join Date: Sep 2018 Location: Europe iTrader: (0)	The thing is that it makes that sound only when the start stop is active. If you switch off the car with the start button...no noise. And the funniest part is when you open the hood there is no Klack anymore should I drive with an open hood. Can somebody confirm this noise or is it only my car.
	Appreciate 0 Quote

09-22-2018, 05:21 PM	#5
Cincinnatus First Lieutenant 123 Rep 396 Posts Drives: 2013 M6 Join Date: Mar 2018 Location: Northeast PA iTrader: (0)	Go ahead and ask my why the auto stop feature was the first thing I disabled. For the couple bucks per year of gas it saves, it's not worth the cost of a new starter motor. And where I'm concerned, there's questionable "eco-value" to it when yiu consider the "carbon footprint" consumed by production of a replacement starter.
	Appreciate 0 Quote

09-23-2018, 04:52 AM	#6
Havy Captain 303 Rep 709 Posts Drives: BMW X5 M50i Join Date: Sep 2018 Location: Europe iTrader: (0)	Whipple, When I turn the car off there is no klack. This is what I don’t understand. I would really appreciate if you could try it and report after. Maybe it is only a relais but for that it is too loud. Cincinnatus it is not about saving some bucks, it’s about the noise it makes. It is a luxury car and it should not make any noises. Monday I go back to BMW.
	Appreciate 0 Quote

09-23-2018, 05:38 AM	#7
spikespiegel Second Lieutenant 88 Rep 238 Posts Drives: BMW M6 comp Join Date: Dec 2016 Location: California iTrader: (0) Garage List 2019 Aprilia RSV4 [0.00] 2015 Land Rover Ran ... [0.00] 2014 MV Agust Rival ... [0.00] 2009 KLR650 [0.00] 2016 Kawasaki KX450F [7.50] 2016 BMW S1000RR [8.50] 2014 BMW M6 [8.00]	the start stop starter is a separate starter motor and not the one you use when you press ignition on. Its designed for many, many start stop applications; and anything over 10 secs or so in idle, it does start saving fuel. I personally don't use it much unless i know i'm gonna be in really bad traffic.
	Appreciate 1 gregmb19.50 Quote

09-24-2018, 07:33 AM	#8
Havy Captain 303 Rep 709 Posts Drives: BMW X5 M50i Join Date: Sep 2018 Location: Europe iTrader: (0)	So, I went to BMW and after the first glance it might be some small issue with the gearbox. hmmm gear box and small issue....that doesn’t fit. Maybe they can fix it with a software update. Keep you posted.
	Appreciate 0 Quote

09-25-2018, 02:17 PM	#9
Havy Captain 303 Rep 709 Posts Drives: BMW X5 M50i Join Date: Sep 2018 Location: Europe iTrader: (0)	So, here is an update. 2 mechanics and the customer service from BMW in Dingolfigen (the plant) told me that this noise is normal. apparently it is a sort of locking device when the engine shut off at the red light and when the engine starts it will unlock and makes the same noise. I am not 100% convinced so I wrote a mail to the gear box manufacturer and asked him if this could be. This gear box (Getrag GS7-D36BG) is also used in the M5 Now, wait and see.
	Appreciate 0 Quote

09-25-2018, 02:19 PM	#10
BMWDriverX Captain 366 Rep 804 Posts Drives: G12 750i X-Drive Join Date: Jul 2017 Location: CA iTrader: (1)	I turned this on today and there was no clack noise, just starts when i release the brake pedal.
	Appreciate 0 Quote

09-26-2018, 01:43 AM	#11
Havy Captain 303 Rep 709 Posts Drives: BMW X5 M50i Join Date: Sep 2018 Location: Europe iTrader: (0)	And what about when your are braking and stop at a red light? Do you here a Klack right after the engine went off?
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10-01-2018, 10:52 AM	#13
Taheemr Captain 280 Rep 731 Posts Drives: M6 GC Join Date: Nov 2011 Location: Mids iTrader: (0)	That noise is normal, my current M6 does it, as did the one before, i have friend s with the M5 and m4, these do it too, dont worry
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10-01-2018, 01:25 PM	#14
Havy Captain 303 Rep 709 Posts Drives: BMW X5 M50i Join Date: Sep 2018 Location: Europe iTrader: (0)	Yeah, thank you Taheemr I went to a BMW branch office today and the chief mechanic who is responsible for M engines and gear boxes noticed it immediately. „yes sir it is normal. This is the sound when the pressure valve open and closes to avoid that the gear box switch into P. All M vehicles with that gear box does it. Some little louder some more quiet but this is what you have to eat when you get this gear box.“
	Appreciate 0 Quote

10-02-2018, 07:22 AM	#15
Taheemr Captain 280 Rep 731 Posts Drives: M6 GC Join Date: Nov 2011 Location: Mids iTrader: (0)	On a related note, when starting your car from cold when engaging gear, forward or reverse say, do you get a delayed reaction and then a thump as the gear engages, I would be interested to know
	Appreciate 0 Quote

10-11-2018, 11:59 AM	#16
Havy Captain 303 Rep 709 Posts Drives: BMW X5 M50i Join Date: Sep 2018 Location: Europe iTrader: (0)	Hi Taheemr, either it is not cold enough or I don’t have that thump as you mentioned.
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