Heater valve busted?

[buzdof]

'85 325e

The heat works on all 4 settings but in order to get heat I need to crank it up to the highest setting then I can reduce the fan speed.

Does this sound like the valve is toast?

[Devil Inc]

Heater valve, no. That controls the hot to cold (left side). Sounds like either the resistor pack or the panel switch(right side).

[buzdof]

The fan works on all settings though, it just takes full blast to initially get heat...

[SpecM]

clogged hearer core maybe?

[buzdof]

Something else I forgot to mention: When I crank it up to high, it blows hot air but if I lower the speed to anything else it will blow hot but it will eventually cool down until I put it back to high then it will go hot again. Obviously something is preventing hot coolant from getting in the heater core but it's still controllable.

[Devil Inc]

Have you tried bleeding the cooling system, just in case it may be air locked?

[buzdof]

I've actually replaced the coolant twice since this started (which was last winter), so I have bled the system a few times.

[allwheeldrive]

Sounds similar to the same issue i'm having with mine. I've checked everything short of taking the heater core out and inspecting that.

Is it possible that the in-line thermostat for the recall on the heater hose could possibly go bad and limit the amount of coolant to go by it? Therefore giving it some heat, but not good heat? Just brainstorming.

[Jean]

The heater core valve gets voltage to open when you turn the left knob on the HVAC control even less than half way towards Hot. As you turn it, it really is mixing the hot air with outside air to get the temp you desire. For example, when you turn the heater knob all the way to the left, you can actually hear the heater core turn OFF or lock, and at the same time you are closing the path for the hot air to get from the heater core to the air vents.... At least that's how I see it's working on my car from looking at it.

I would confirm that your valve opens regardless what speed your FAN is on first.

[allwheeldrive]

The heater core valve gets voltage to open when you turn the left knob on the HVAC control even less than half way towards Hot. As you turn it, it really is mixing the hot air with outside air to get the temp you desire. For example, when you turn the heater knob all the way to the left, you can actually hear the heater core turn OFF or lock, and at the same time you are closing the path for the hot air to get from the heater core to the air vents.... At least that's how I see it's working on my car from looking at it.

I would confirm that your valve opens regardless what speed your FAN is on first.

At least with mine, i can hear the solenoid operate when turning the temp dial off of full cold. I believe in the diagram, its 20* when it opens the valve.

[buzdof]

I can hear the solenoid activating also and it is very obvious when it changes from hot to cold air, so that works just fine as far as I can tell.

On my way home last night and driving to work this morning, my heat was pretty shitty. The car came up to temp ok but it took FOREVER to get any heat. Does this pretty much mean a blocked heater core?

[duckBoy]

Similar case sort of:

I get heat while driving, but once i come to a stop or idle the heat drops to cold.

I have no clue what's wrong.

[Rocla]

The heater core valve gets voltage to open when you turn the left knob on the HVAC control even less than half way towards Hot.

The heater valve is open when it's NOT getting voltage. If you take wire off from valve it's open all the time.

They can stuck to closed position.

[StereoInstaller1]

The heater valve is open when it's NOT getting voltage. If you take wire off from valve it's open all the time.

They can stuck to closed position.

Mine did, and I drilled that bitch. Seriously, broke and desperate, no local parts...fuck it, I am drilling.

Ran like that for 2 years.

I really think the OPs issues is more about coolant flow than anything. Take that shit apart and check it!

[Jean]

The heater valve is open when it's NOT getting voltage. If you take wire off from valve it's open all the time.

They can stuck to closed position.

Thanks for the correction. :D