A/C Problems... Aux Water Valve?

[ElNormo]

Howdy,

I've been having strange A/C problems where, when running the A/C, obviously heated air is coming out some vents. Specifically, it's coming out the vents along the bottom of the windshield, the two triangular vents near the side mirrors, and the vents at your feet. The "face-level" vents blow nice cold air.

This doesn't happen all the time. It was "on again, off again" last summer. It behaved fine for a few weeks, then misbehaved for a few weeks, etc.

Now that it's getting warm again, I asked our friendly mechanic (a bmw guru) to check it out. He diagnosed it as a faulty auxiliary water valve.

Unfortunately, my Bentley Guide is at home. Can anyone enlightened me as to what this water valve does, and how it might be causing my symptoms? I was honestly expecting a stuck air flap or a problem with the heater valve.

Thanks,

Norman

[ElNormo]

The valve regulates the amount of hot coolant that goes through the heater core. And yes, they do break down in the default open position. Usually one side only. Sometimes tapping it with a hammer can keep it working orderly for a while, but replacement is just around the corner. Not so hard to do.

Wait a sec: Isn't the heater valve and aux water valve the same thing?

Not sure... I've never gotten a good feeling as to what the heater valve does, or how to replace it. Honestly, I haven't taken the time to dig through the Bentley Manual, I'm sure it's there someplace.

Thanks for the help though, be interested if anyone else has any opinions too!

Norman

[Morgenster]

Howdy,

I've been having strange A/C problems where, when running the A/C, obviously heated air is coming out some vents. Specifically, it's coming out the vents along the bottom of the windshield, the two triangular vents near the side mirrors, and the vents at your feet. The "face-level" vents blow nice cold air.

This doesn't happen all the time. It was "on again, off again" last summer. It behaved fine for a few weeks, then misbehaved for a few weeks, etc.

Now that it's getting warm again, I asked our friendly mechanic (a bmw guru) to check it out. He diagnosed it as a faulty auxiliary water valve.

Unfortunately, my Bentley Guide is at home. Can anyone enlightened me as to what this water valve does, and how it might be causing my symptoms? I was honestly expecting a stuck air flap or a problem with the heater valve.

Thanks,

Norman

The valve regulates the amount of hot coolant that goes through the heater core. And yes, they do break down in the default open position. Usually one side only. Sometimes tapping it with a hammer can keep it working orderly for a while, but replacement is just around the corner. Not so hard to do.

Wait a sec: Isn't the heater valve and aux water valve the same thing?

[pingu]

I thought that there were solenoid valves to control the water flowing into the heater core, and an auxiliary water pump to pump water through the heater core (e.g. if the engine is idling) ?