Hi - when ever i turn on the heat from any setting but the coldest i can hear the heater valve knocking (opening and closing quite quick) does any one know of a reason for this - i have whatever heat i want but the valve just opens and shuts causing that annoying sound.
at the moment i am going to check the cabin temp sensor, but i cant find it?! does anyone know where it is?
thanks
liam
cabin temp sensor - heater vlave
Moderator: martauto
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ian332isport
- E30 Zone Team Member

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- Location: West Sussex
Liam,liam012 wrote:Hi - when ever i turn on the heat from any setting but the coldest i can hear the heater valve knocking (opening and closing quite quick) does any one know of a reason for this - i have whatever heat i want but the valve just opens and shuts causing that annoying sound.
at the moment i am going to check the cabin temp sensor, but i cant find it?! does anyone know where it is?
thanks
liam
That sounds like you have the heater hoses swapped over at the bulkhead. Basically the water is flowing the wrong way through the valve.
It's caused by the flow of water lifting the valve off it's seat. Once it's lifted, the pressure is reduced, and the valve clonks closed again.
Ian.
If it aint broke - Modify it...
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Brianmoooore
- E30 Zone Team Member

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Yes, almost certainly some numpty has managed to cross over the two heater hoses at some time in the past.
The cabin temperature sensor should be behind the little projecting grill top left of the heater knob, but you won't find it, as I'm fairly sure BMW never got around to fitting it to any E30.
The cabin temperature sensor should be behind the little projecting grill top left of the heater knob, but you won't find it, as I'm fairly sure BMW never got around to fitting it to any E30.
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liam012
- E30 Zone Camper

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so how does your cabin know if its 27 degrees or not?!!
thanks a million though - that knocking has been driving me demented - i reckon you are right coz the knocking increases with acceleration which would be i presume the coolant speeding up due to water pump,
will let u know
thanks
thanks a million though - that knocking has been driving me demented - i reckon you are right coz the knocking increases with acceleration which would be i presume the coolant speeding up due to water pump,
will let u know
thanks
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kam-325i
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When you have to open the windows.......liam012 wrote:so how does your cabin know if its 27 degrees or not?!!
Pete don't care about colour, He would shag a rainbow if he could find the end of it....


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liam012
- E30 Zone Camper

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you were right!!
problem solved -
a big thanks
regards
liam
problem solved -
a big thanks
regards
liam
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tourer-dan
- E30 Zone Regular

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- Location: romford, essex
There is a cabin temp sensor up in the dash somewhere, I think to the left hand side of the ducting around the matrix.
