Bleeding/replacing the coolant
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Joined: Jun 2008
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Bleeding/replacing the coolant
Searched the forums, read some interesting stuff, but didn't find what I was looking for.
My heater "valve unit" is making a sort of "clicking" noise. Heat works fine, A/C works fine. Vents seem to adjust fine as well.
Doesn't seem to happen when the car is cold, only when the engine is warm. At first I thought it was a vent adjusting motor, which I understand is a common part to fail. What threw me off was that the click seems to occur at about 1 second intervals. I understand the vent motors should produce a clicking every 7 mins or so.
If I place my hand on the valve unit, I can actually feel the clicking.
I thought I'd at least try to drain and replace the coolant. Is it possible that there could be air in the system causing this noise to occur?
I perused the Bentley manual for information, but their procedure seemed a little confusing due to their extensive use of special tools.
Any speculation on what might be causing the problem would also be appreciated. Don't see the point in draining coolant unless really necessary, assuming it's even possible for me to do.
FWIW, the click also occurs with ignition "ON", as well as in REST mode.
Thanks in advance!
*EDIT*
Forgot to mention that my coolant expansion reservoir sits JUST below the MIN mark. Hasn't moved, so I'm sure I'm losing coolant. At least I hope not.
My heater "valve unit" is making a sort of "clicking" noise. Heat works fine, A/C works fine. Vents seem to adjust fine as well.
Doesn't seem to happen when the car is cold, only when the engine is warm. At first I thought it was a vent adjusting motor, which I understand is a common part to fail. What threw me off was that the click seems to occur at about 1 second intervals. I understand the vent motors should produce a clicking every 7 mins or so.
If I place my hand on the valve unit, I can actually feel the clicking.
I thought I'd at least try to drain and replace the coolant. Is it possible that there could be air in the system causing this noise to occur?
I perused the Bentley manual for information, but their procedure seemed a little confusing due to their extensive use of special tools.
Any speculation on what might be causing the problem would also be appreciated. Don't see the point in draining coolant unless really necessary, assuming it's even possible for me to do.
FWIW, the click also occurs with ignition "ON", as well as in REST mode.
Thanks in advance!
*EDIT*
Forgot to mention that my coolant expansion reservoir sits JUST below the MIN mark. Hasn't moved, so I'm sure I'm losing coolant. At least I hope not.
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Joined: May 2003
Posts: 3,295
Likes: 11
From: CT
yes, been dealing with this for the past couple of days.
Do you "feel and hear the clicking by placing your hand on one of the heater hoses going through the firewall?
If it's kind of like a thumping sound, it's the after run pump for the "rest" feature and you can just disconnect it. It's one of the purple plugs next to the master cylinder.
It could also be one of the flap motors. I had one that went bad and it clicked continuously. You can see three of them very clearly on the driver side if you remove the side panel. Just look for the bright yellow connectors.
On the pass side, two are very accessible and one is not.
If you run basic settings under HVAC it should make the noise when it gets to that motor (but not always).
I think the diagram in the Bentley is a little busy so an easy way to identify which motor you're dealing with is to disconnect it and check for fault codes. It will throw a code since there's no + voltage and clearly identify the motor you're working on.
They're easy to swap, just two screws. Check the flap and make sure it's not binding up. If you get a new motor you'll probably have to move it into the right position in order to get it onto the plastic flap piece.
In the Bentley, there's a picture which shows which pins to connect 12v and ground. A 9v battery would probably work, you just need to rotate the shaft.
Bob
If it's kind of like a thumping sound, it's the after run pump for the "rest" feature and you can just disconnect it. It's one of the purple plugs next to the master cylinder.
It could also be one of the flap motors. I had one that went bad and it clicked continuously. You can see three of them very clearly on the driver side if you remove the side panel. Just look for the bright yellow connectors.
On the pass side, two are very accessible and one is not.
If you run basic settings under HVAC it should make the noise when it gets to that motor (but not always).
I think the diagram in the Bentley is a little busy so an easy way to identify which motor you're dealing with is to disconnect it and check for fault codes. It will throw a code since there's no + voltage and clearly identify the motor you're working on.
They're easy to swap, just two screws. Check the flap and make sure it's not binding up. If you get a new motor you'll probably have to move it into the right position in order to get it onto the plastic flap piece.
In the Bentley, there's a picture which shows which pins to connect 12v and ground. A 9v battery would probably work, you just need to rotate the shaft.
Bob
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Joined: Jun 2008
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Re: yes, been dealing with this for the past couple of days.
Yes. I can feel the clicking by placing my hand on the hoses as well. Actually, it is more like a "thumping"! Bump bump, bump bump...
It's definitely not a "clicking" by definition of the word.
Here's the catch, IF I REMEMBER correctly, unplugging the secondary coolant pump does nothing for the noise...
I can hear the pump operating, and it is audible, but just a "whirring" sound. Sounds normal to me.
It's definitely not a "clicking" by definition of the word.
Here's the catch, IF I REMEMBER correctly, unplugging the secondary coolant pump does nothing for the noise...
I can hear the pump operating, and it is audible, but just a "whirring" sound. Sounds normal to me.
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