heater only works driver side

[Nota TR5 man]

Ok Zedites do any of you have any idea why or how I can fix my heater that only works on offside on my 2004 Z4 3.0i. The screen demist and passenger outlets all fail to give heat but are blowing air.

 

[Street]

Bad news I’m afraid. It’s almost certainly a clogged heater matrix under the dash from my experience.

You can start by trying to rinse out the matrix with simple hose pipe. I’ve had some success to improve some over the years by running central heating cleaner through it over night using a water pump. Most extreme is a matrix replacement and it’s probably the most intrusive job of any. A full dash out job

 

[McSwerve]

Mine is a similar age and has the same problem.
I’ve never investigated, but probably should do.

Is there a fan blowing air to the near side, but it’s just not hot?

 

[Nota TR5 man]

Bad news I’m afraid. It’s almost certainly a clogged heater matrix under the dash from my experience.

You can start by trying to rinse out the matrix with simple hose pipe. I’ve had some success to improve some over the years by running central heating cleaner through it over night using a water pump. Most extreme is a matrix replacement and it’s probably the most intrusive job of any. A full dash out job

Thank you for this sad news that seems to be an awful job to cure. I will wait until I get the urge to sort the damn thing. At least the fan works well and I have lived with it for 3 years+. I was hoping that its just some piece of trim that blocks the heat.

 

[enuff_zed]

Bad news I’m afraid. It’s almost certainly a clogged heater matrix under the dash from my experience.

You can start by trying to rinse out the matrix with simple hose pipe. I’ve had some success to improve some over the years by running central heating cleaner through it over night using a water pump. Most extreme is a matrix replacement and it’s probably the most intrusive job of any. A full dash out job

Thank you for this sad news that seems to be an awful job to cure. I will wait until I get the urge to sort the damn thing. At least the fan works well and I have lived with it for 3 years+. I was hoping that its just some piece of trim that blocks the heat.

You can try disconnecting the hoses at the bulkhead and flushing back and forth until you get bored. That 'may' shift some crud but not a complete cure.

Simplest answer is to remove the passenger seat. Then no-one will ever notice.

 

[Nota TR5 man]

Mine is a similar age and has the same problem.
I’ve never investigated, but probably should do.

Is there a fan blowing air to the near side, but it’s just not hot?

Indeed the fan blows so it will poorly demist in most instances and in truth it was only the wife complaining that her side was cold that I noticed.

 

[Joez4]

I have this problem on my car and replacing pretty much everything in the coolant system, flushing it, filling with fresh coolant and bleeding hasn't made much difference all the parts needed replacing anyway.

I imagine the heater matrix is split in two and must have some sort of flow and return like a radiator in a central heating system so if its blocked the coolant just bypasses it and returns to the expansion tank as both pipes to the matrix are red hot to touch and the drivers side gets really hot.

 

[enuff_zed]

No it's just one matrix, like a radiator on its side. So lots of fins run horizontal with a small tank section at each end that connects them.
But the entry and exit are both at the drivers end, so if the far end silts up the water pushes up as far as it can, then simply gives up and comes back out from the same end.

 

[Joez4]

OK thanks for the info.

I found this if anyone is interested aftermarket matrix which rectifies the fault in the original. If it wasn't so difficult to get to I think I would replace it with this.

https://www.ebay.co.uk/itm/304343655964?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=ezoKzpp7R7O&sssrc=4429486&ssuid=n9JpnKwVSkS&var=&widget_ver=artemis&media=COPY

 

[Nota TR5 man]

Thanks for the input guys I will wait until I feel the urge to fix it!

 

[enuff_zed]

Thanks for the input guys I will wait until I feel the urge to fix it!

Be warned that even when you've got it out of the car it still isn't all that easy to get the matrix out.
Could be worth keeping your eyes peeled for a complete unit that can be proved to work ok.

 

[BigDaddy]

I’m going to flush my matrix out as soon as I get a few hours to solve the same problem. Just wondering what diameter the hoses are? Just standard garden hose pipe diameter?