# 2001 740i heater makes noise every 2-3 seconds constitently (tok tok.....tok tok)



## emmsys (Nov 6, 2005)

Hi,

The weather is getting cooler here in Montreal and I'm starting to use the heater again. When I turn it on, regardless of speed I hear a noticeable tapping sound every few seconds. It's a consistent sound, like a "tok tok....(2-3 seconds)...tok tok...(2-3 seconds)...". When I turn off the heater the sound goes away instantly. Anyone familiar with this? When I put the radio on it's not noticeable but still...

On a side note, as soon as the temperature drops, the "Check engine" goes on. <sigh>. Do I have to warm up the car FULLY before driving away? I can't find the engine block heater...please tell me a $90k car comes equipped with a block heater. Please. My brother's Ford Focus has one, and so did my Chrysler Concorde (battery warmer too!).

e


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## M.Wong (Jan 9, 2003)

emmsys said:


> When I turn it on, regardless of speed I hear a noticeable tapping sound every few seconds. It's a consistent sound, like a "tok tok....(2-3 seconds)...tok tok...(2-3 seconds)...".
> 
> The "Check engine" goes on.


Is the sound coming from behind the center vents? Or the engine area? Or somewhere else?

Full warm up is not necessary. You need to have the error code(s) checked when the Check Engine Light comes on so you know what it's trying to tell you. Down here, AutoZone and other auto parts stores will read your codes for no charge.


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## emmsys (Nov 6, 2005)

Hi,

Of course when I went to check this morning the sound was gone  . But I do remember it coming from the center console. 

e


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## M.Wong (Jan 9, 2003)

Hard to say based on your description, but here's a possibility on fan noise.

Or, does it sound like a jammed vent flap trying to open or close? That could be a stepper motor problem.

Now is also a good time to check and replace your recirculation filters under the dash.

Clean vs dirty


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## emmsys (Nov 6, 2005)

Hi,

The Stepper motor sounds like the issue! I did have the heater on Auto today which is not what I normally have it set to. Maybe that's why the issue is gone. I'll check after work. A BIG thank you for giving me some direction. I've had all of the common problems so far and I should have assumed this was another one hehe. I hope it's not expensive. I'll keep you posted.

e


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## emmsys (Nov 6, 2005)

Hi,

I found the exact problem:

http://www.bimmerboard.com/forums/posts/203484/

I never heard the gurgling sound until the car was extremely quiet. It's raining now so I'll check out which of the two problems my car is experiencing. In either case it doesn't seem so bad. I'll post which fixed mine.

Thanks!!!!

e


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## M.Wong (Jan 9, 2003)

Gurgle is another common problem, but I would call it different than a "toc toc" noise. 

The gurgle sound exactly like a coffee percolator, percolating.  More obvious on a warm and humid day.


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## bmwenvy (Oct 11, 2006)

Sounds like the heater valves opening and closing. The heater valve unit is mounted to the firewall in the engine compartment and can sound like it is coming from right behind the dash. The opening and closing of the valves is normal and you will hear it normally, how loud? that's hard to say without hearing it


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## emmsys (Nov 6, 2005)

Hi,

Actually what I thought was a "tok tok" sound is actually the bubbling/gurgling sound. I never got close enough to hear it until I shut everything off. That's when I heard water. I'm going to see if the local dealer will fix it for no charge.

On a side note, I fixed the leaky lumbar support problem (phew it was tough getting those panels off the back of the seats!) and fixed that cheaper-than-Lada cup holder.

Thanks again for the info.

e


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## jessicajiw10 (Nov 3, 2006)

*How do you fix the cup holder?? HELP*

Hi, my cup holder on my pp 740i just broke. It is wierd because nothing happened, it just seemed like one day the front part started falling out from the back. Can anyone help? I cant even find a broken part on it.


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## M.Wong (Jan 9, 2003)

jessicajiw10 said:


> Hi, my cup holder on my pp 740i just broke.


You should seach the boards for cupholder first, and post this as a new thread as well... otherwise, people will be reading this post only if they are interested in the AC noise issue...


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