No blow from my cabin vents in the Z4...

gord

gord

gord

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Well, it appears my Z4's lost its blow.. thing is I've never had to have it on and only tried it today out of novelty.. but to my dismay its a no go into the cabin.

No matter if its air con, recycled air, warm, cold, max chill.. doesnt matter.. you get a faint whisper out of the passenger side vent. The others are barely noticeable without using your cheek up against it. The centre vents give off a nice whistle at max with the twiddlers open fully, but still no blow.

Fan can be on full whack and you can hear it loud, its working behind the scenes. Took a look under the hood but I can't see anything wrong per se. No loose hoses, compressor seems to be OK.. but this isn't really an air con issue. The issue appears to be something is stopping air getting into the cabin completely.

Are there any common issues or Z4 specific ones I should be looking out for? I've done my fair share of Googling, but just coming up with people's air con issues and mine isn't a cold air issue.. max temp.. it still doesnt blow. It just gives some residual heat passing up from the matrix, I imagine.

I'm just going to go de-construct the glove-box to take a look at the filter and see if that's blocked... but tomorrow it's a phonecall to the place that serviced it about a month ago.. and then probably a phone call to my nearest dealer.

Any other ideas / hints / tips / free sex / business ideas are much appreciated.
 
Your heater blower motor has probably failed. This is common on E39 and E46, I've not heard of it on a Z4 but given the Z4 is full of E46/E39 bits I'd not be suprised if its the same component.

Unfortunately the dashboard needs to come out in order to get it to it. I think I paid £350 to get mine replaced, I took it to BMW in the end so I'd have somebody to cry at if it rattled after the job was done.
 
mjt said:
Are the vents open?
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To the max and back again.. tried everything with them.. they make no difference to the air coming through.. as its not..
[TW]Fox;16705266 said:
Your heater blower motor has probably failed. This is common on E39 and E46, I've not heard of it on a Z4 but given the Z4 is full of E46/E39 bits I'd not be suprised if its the same component.
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Fingers crossed it hasn't.. would this affect cold air too?
 
It means you get no airflow out of the vents. When you say you can hear the fan - can you hear the van inside the dash or are you talking about the electric fan for the AC etc inside the engine bay?
 
[TW]Fox;16705332 said:
It means you get no airflow out of the vents. When you say you can hear the fan - can you hear the van inside the dash or are you talking about the electric fan for the AC etc inside the engine bay?
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The noise comes from up front on the left hand side.. I assumed that was the blower for the cabin flow. You can easily hear it inside and outside the car, but its not an electric sort of fan sound.

Just performed some kung fu on it and had the cabin filter out.. its as clean as your hat.. tried it without it and the same effects.. no gusts! So it's not that.

I fear you may be right Mr Fox.
 
You need to be more specific. Where is the noise coming from?

a) Inside the dashboard

b) At the front of the engine bay
 
And it's noticeably audiable? Strange, maybe the heater blower is working fine. I guess the next suggestion is the final stage resistor pack but they dont normally cause a complete loss of blower, just erratic blower.

Can you control the pitch of the noise by using the rotary knob on the dashboard?
 
The main blower control, big bad centre jobby? Or the individual vent controls.

The main blower control on low is inaudible, mid way is acceptable, full blast is that loud fan sound you get when you are trying to clear that mist from inside your car on a cold morning.

Individual vent controls make no difference to the sound as there is little air passing through them. The only thing you can make happen is a whistle from the central two dash vents, open them fully with main fan on full for a whistle.. close them for no whistle.. but still no hurricane.
 
I don't know the exact make up of the Z4s system but there might be some ducting/tubing/pipework from the motors to the vents themselves, once of which along the way might of come loose.
 
gord said:
The main blower control, big bad centre jobby? Or the individual vent controls.

The main blower control on low is inaudible, mid way is acceptable, full blast is that loud fan sound you get when you are trying to clear that mist from inside your car on a cold morning.

Individual vent controls make no difference to the sound as there is little air passing through them. The only thing you can make happen is a whistle from the central two dash vents, open them fully with main fan on full for a whistle.. close them for no whistle.. but still no hurricane.
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Right so your blower motor obviously is working then if the main blower control directly affects fan noise.

Running out of ideas but it could be the final stage resistor.
 
[TW]Fox;16705639 said:
Right so your blower motor obviously is working then if the main blower control directly affects fan noise.

Running out of ideas but it could be the final stage resistor.
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Eurgh.. I dislike problems I can't fix. Just had another nosey under the bonnet near the fan box.. nothing extraordinary there. It's dark and raining, and I'm now out of ideas too so this looks like a dealer call.
DiamondMark said:
Do they have a cabin filter that gets blocked?
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Yep, just performed gymnastics to get it out and it's fine.
 
gord said:
Eurgh.. I dislike problems I can't fix. Just had another nosey under the bonnet near the fan box.. nothing extraordinary there. It's dark and raining, and I'm now out of ideas too so this looks like a dealer call.

Yep, just performed gymnastics to get it out and it's fine.
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Hows the air pressure in the cabin filter 'box'? Just to tell if the fan is really blowing at full whack or not, and whether the blockage is before or after the cabin filter.

This is assuming the fan is before the filter, or it sucks through the filter. Probably the latter thinking about it :/.
 
NickXX said:
Good call - yes, there is a microfilter at the back of the engine bay. Turn the clips and take it out entirely to see if that makes a difference.
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I took out the one in the cabin.. behind the glove box.. I didn't meddle with the one in the engine bay.. I didn't realise there was a filter there too. I'll take a look at lunch time to see if its easy to remove.

Chris1712 said:
Hows the air pressure in the cabin filter 'box'? Just to tell if the fan is really blowing at full whack or not, and whether the blockage is before or after the cabin filter. This is assuming the fan is before the filter, or it sucks through the filter. Probably the latter thinking about it :/.
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I thought about this after I had put it all back together. Might check it out tonight if I feel I'm up for more Z4 passenger side jujitsu.

iaind said:
Is the air coming out anywhere else? Can you direct it to the feet or windscreen?
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Nope, nowhere gives a good gust of air.. no matter which way its directed. The only vent to give anything near a blow is the one inside the door on the dash on the passenger side.. I can actually feel that with my fingers a little.. its nowhere near what it should be though.

Cheers for all the help so far.
 
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