E30 Zone

I have an 318is but the heater is just blowing out hot air.

Its going in to see an electrician guy tomorrow and the guy who i bought it off said it was just due the heater valve wiring which was found behind the console on the passenger side.

does this sound correct, and what should I tell the electrician guy?

BMWReid wrote:I have an 318is but the heater is just blowing out hot air.

Not quite sure what the problem is here

It won't blow out cold air!

There's an electric valve on the LH side of the heater box (one of the pipes that goes through to the engine bay is actually part of the valve), which can be sort of accessed by removing the inspection panels above and to the right of the glovebox, or more easily reached by removing first the rear centre console, followed by the front centre console.
The default state of this valve is open, allowing hot water to the heater matrix. With the heater temperature control at fully cold, a switch is closed which applies 12 volts to the valve, via the only fuse on an E30 which isn't in the fuse box, closing the valve and cutting off hot water flow to the matrix. When the temp. control is moved a few degrees off of cold, the switch opens, and the valve opens fully. The actual temperature of the air coming from the heater is then controlled by the rest of the arc of the control knob, via a bowden cable which operates a blender flap, mixing cold and hot air, inside the heater box.
If you car is only giving hot air, then you have two faults - one with the valve and one with the blender, since even if the valve isn't closing, you should still get almost cold air from the blender.

Apologies to hijack this thread but I too have a heater issue with my 318is I only get barely warm air from my vents when the heater switch is in the full hot position , it does seem to get colder when I turn to the cold position however so I think the switch is at least partly open.mine seems to blow warmer air in defrost position than if the cabin vents are opened.
On reading the wiki I am suspecting the heater valve to be at fault. I have however just fitted a new rad and doubting myself re the bleeding thereof and am wondering if an airlock somewhere could display the same symptoms, im pretty sure all the air is out though
Brianmoore If the default fail for the heater valve is open it should blow only hot air is that right? Or can it partially fail

Thanks

gjj107 wrote:Apologies to hijack this thread but I too have a heater issue with my 318is I only get barely warm air from my vents when the heater switch is in the full hot position , it does seem to get colder when I turn to the cold position however so I think the switch is at least partly open.mine seems to blow warmer air in defrost position than if the cabin vents are opened.
On reading the wiki I am suspecting the heater valve to be at fault. I have however just fitted a new rad and doubting myself re the bleeding thereof and am wondering if an airlock somewhere could display the same symptoms, im pretty sure all the air is out though
Brianmoore If the default fail for the heater valve is open it should blow only hot air is that right? Or can it partially fail

Thanks

First thing to check is that the hoses are connected the right way around to the heater under the bonnet. Hose from the rear of the head goes to the lower heater stub pipe.
Heater valve is a mechanical device, so all modes of failure are possible. I've always found them totally reliable though, other than a tendency to come apart in the middle and leak.

Hoses correctly routed , both in and out of the matrix pipes seem to get hot so I think I have through flow just very little heat coming into the car
Temperature gauge reaches just short of halfway and is then steady

Roll on summer!!!