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HELP WITH HEAT

Old 01-10-2019, 10:09 PM
  #1  
Twilightblue28A
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Default HELP WITH HEAT


Torre' Photograph
I removed the fresh air servo item #2 referred to in Torr'e's photograph. I taped the cowl vents and I receive hot air at idle and at high speeds.
Both center vents, and all three (3) vents on the passenger side are delivering hotter air compared to the three (3) vents on the driver's side ie; defroster, dash and the vent that provides heat to the floor.
Which servo motor most likely is causing the temperature difference. Servo motor #3 identified as the footwell servo motor in Tore's photograph or a servo motor inside the cabin, driver's side, not identified in Torre's photograph?
Please refer to Torre's photograph so we use the same description.
(#2 and #3 are in the frunk as shown in Torre's photograph)
The servo motor inside the cabin is not shown in Torre's photograph.
Thank you.
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Old 01-10-2019, 10:20 PM
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mike cap
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As I explained before it’s the mixing valve motor in the drivers side footwell by your left calf. There’s a carpeted piece to remove for access. The mixing valve is inoperative and needs to be replaced.

It is not allowing enough hot heat exchanger air past to mix w cabin or unheated outside air.

Simple to replace and common problem.
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Old 01-10-2019, 10:55 PM
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Twilightblue28A
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Originally Posted by mike cap View Post
As I explained before it’s the mixing valve motor in the drivers side footwell by your left calf. There’s a carpeted piece to remove for access. The mixing valve is inoperative and needs to be replaced.
Thanks Mike,

I won't remove #3 the footwell servo located in the frunk in Torre's photograph. I will remove the servo motor inside the cabin, driver's side, behind the carpet near the frunk release.
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Old 01-11-2019, 09:50 AM
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Originally Posted by Twilightblue28A View Post
Thanks Mike,

I won't remove #3 the footwell servo located in the frunk in Torre's photograph. I will remove the servo motor inside the cabin, driver's side, behind the carpet near the frunk release.
Sounds like a plan. The one behind the carpet cover in the footwell is easy to get to other than you will be down on your hands and knees to remove it.
Andy
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Old 01-11-2019, 07:04 PM
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[QUOTE=mike cap;15557270]
As I explained before it’s the mixing valve motor in the drivers side footwell by your left calf. There’s a carpeted piece to remove for access. The mixing valve is inoperative and needs to be replaced.

It is not allowing enough hot heat exchanger air past to mix w cabin or unheated outside air.

Simple to replace and common problem.[/QUOTE
Mike,
I already removed the fresh air servo. I am also removing the driver's and passenger's side servo's and sending the group to Partisan. I have been that both interior servo's often fail together.
Any suggestions where the interior servo's are located and what must be removed to access the servo's will be greatly appreciated. I have attached photographs of the driver's side, interior carpeting and frunk release.

Driver's side carpeted area by my feet.

Driver's side carpeted area.

Driver's side carpeted area. Do I remove the screws from the release to provide carpeted cover to be removed?

Driver's side by frunk release

Driver's side frunk release.
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Old 01-11-2019, 08:07 PM
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Please remember this started with my car not getting hot air at high speeds. I removed the fresh air servo motor. I taped the cowl vents and the car delivered heat at high speeds. While test driving, I noticed that the heated air was not as hot as the two center vents and all of the vents on the passenger side.
I have been given advice to replace the servo motor on the driver's side, inside my car. Ii was told that it is common for both interior servo motors to fail at the same time. I figured I might as well take out the servo motor on the passenger's side, inside my car, and send the three (3) servo's to Partisan in Germany for rebuilding. Hopefully, rebuilding the three (3) servo's will correct both issues.
What do you think?
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Old 01-11-2019, 10:23 PM
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mike cap
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Originally Posted by Twilightblue28A View Post
Please remember this started with my car not getting hot air at high speeds. I removed the fresh air servo motor. I taped the cowl vents and the car delivered heat at high speeds. While test driving, I noticed that the heated air was not as hot as the two center vents and all of the vents on the passenger side.
I have been given advice to replace the servo motor on the driver's side, inside my car. Ii was told that it is common for both interior servo motors to fail at the same time. I figured I might as well take out the servo motor on the passenger's side, inside my car, and send the three (3) servo's to Partisan in Germany for rebuilding. Hopefully, rebuilding the three (3) servo's will correct both issues.
What do you think?
Its common for the mixing valves to fail and be partially open or closed and for it to go unnoticed. You’d get hot air if requested on one side and maybe lukewarm on the other side. Not something you’d notice right away if at all.

The trunk servos are unrelated to the mixing valves right and left.

Long time since my drivers side was replaced but I think the pictured screws and plastic piece comes out and there are other screws hidden in the carpet and near the footrest.

Not sure why you sent perfectly good and operating servos away for refurb. You have a low mileage garage queen so doubt they see much use. It seem to me the fresh air servo would be the most active unit and most prone to fail.
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Old 01-11-2019, 11:13 PM
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Originally Posted by mike cap View Post


Its common for the mixing valves to fail and be partially open or closed and for it to go unnoticed. You’d get hot air if requested on one side and maybe lukewarm on the other side. Not something you’d notice right away if at all.

The trunk servos are unrelated to the mixing valves right and left.

Long time since my drivers side was replaced but I think the pictured screws and plastic piece comes out and there are other screws hidden in the carpet and near the footrest.

Not sure why you sent perfectly good and operating servos away for refurb. You have a low mileage garage queen so doubt they see much use. It seem to me the fresh air servo would be the most active unit and most prone to fail.
I appreciate your response as well as any other members help.
As I understand, my car has two (2) seperate issues:
1. At high speeds, I wasn't getting heat inside of the car until I slowed or idled, and under slower speeds or at idle my car delivered heat. It was suggested that the lack of hot air was due to an innoperative fresh air servo motor located in the frunk. It was further suggested that I tape the cowl vents, test drive the car to determine if I had heat at high speeds, and I do. The conclusion was to rebuild the fresh air servo motor. I have removed the fresh air servo from the car for rebuilding.
2. The second issue is what you and I are both describing: the temperature from all of the vents is less hot compared to the temperature delivered from both center vents and all three vents on the passenger side. The recommendation was to replace the servo motor inside the car, driver's side, near my thigh. I have posted photographs of the driver's side in order to identify what must be removed to access the servo motor for rebuilding.
Issue 1, no heat at high speed will be corrected by rebuilding the fresh air servo motor. Issue 2, temperature difference, will be corrected by rebuilding the servo motor located inside of my car, driver's side, near my thigh.
Please advise whether or not I'm clear with respect to the scope of work required to address both issues.
Thank you and any others help in advance.
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Old 01-12-2019, 06:46 AM
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Any problem with the HVAC servos is not diagnosed by observing the air streams or temperatures, but by testing the servos by using the control ***** on the CCU.
Our DIY pages contains a test procedure for all servos and fans, this is done in ten minutes.
Cheers,
Tore
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Old 01-13-2019, 01:44 PM
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Twilightblue28A
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Originally Posted by ToreB View Post
Any problem with the HVAC servos is not diagnosed by observing the air streams or temperatures, but by testing the servos by using the control ***** on the CCU.
Our DIY pages contains a test procedure for all servos and fans, this is done in ten minutes.
Cheers,
Tore
I have additional information on my car. As you may recall, my car was not getting heat at highway speeds, but when I slowed or stopped, my car delivered heated air. I followed a members advice and taped the cowl vents and took my car for a test drive. I received heated air at high speeds. I removed my fresh air servo for rebuilding.
While driving, I felt that the heated air from both center vents and the three passenger vents was hotter compared to the three vents on the driver's side.
This morning, I physically removed the driver and passenger side covers, inside the car, in order to access both servo motors inside of my car. I removed both tubes connected to both servo motors.
I could physically see both dampers open and close as I demanded more heat from the temperature control.
That's telling me that both servo motors inside the car are both operating.
What is next to check to determine why my cars heat is hotter from both center vents and all of the passenger side vents compared to the vents on the driver's side.
I will appreciate your help. Thank you.
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Old 01-13-2019, 02:06 PM
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Twilightblue28A
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Originally Posted by mike cap View Post
As I explained before it’s the mixing valve motor in the drivers side footwell by your left calf. There’s a carpeted piece to remove for access. The mixing valve is inoperative and needs to be replaced.

It is not allowing enough hot heat exchanger air past to mix w cabin or unheated outside air.

Simple to replace and common problem.
FYI: I operated the temperature control repeatedly to ensure that both Motors inside my car weren't operating intermittently. They both work consistently.
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Old 01-13-2019, 03:12 PM
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Old 01-13-2019, 06:28 PM
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Twilightblue28A
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Originally Posted by ToreB View Post
Any problem with the HVAC servos is not diagnosed by observing the air streams or temperatures, but by testing the servos by using the control ***** on the CCU.
Our DIY pages contains a test procedure for all servos and fa

Driver's side closed control not asking for heat.

Driver's side with temperature control asking for maximum heat (red dot) Damper is wide open.

Passenger's side. No temperature demand. Damper is closed.

Passenger's side. Maximum temperature to red dot. Damper is wide open.

Cheers,
Tore
I disconnected both heat tubes that come from my engine bay to the servo motors and damper assemblies inside my car. I started my car, let it idle for about five (5) minutes. The temperature gauge on my instrument panel wasn't registering any operating temperature. I took the temperature on the driver's and passenger's side heat tube and I recorded 160 degrees from both heat tubes. (After five (5) minutes.
I called for maximum temperature on the driver's side and the passenger's side and the dampers moved from fully closed to fully opened positions (See above photographs)
I connected the driver's and passenger's heat tubes to the servo motor and damper assemblies.
When my car reached normal operating temperature I recorded the following temperature readings in Fahrenheit, using a commercial thermometer. All readings were taken at idle, fan set to maximum speed (4) and temperature control set to maximum heat (red dot)
I could not record the temperatures while driving because of safety.
Driver Side. P.assenger's Side

Center vents. 128. 128
Defroster. 128. 138
Vent. 118. 144
Feet. 116. 160 plus

This started when I wasn't getting heat at high speeds. The slower, the more heat I received. At the request of another member. I taped the cowl vents and removed the fresh air servo motor for rebuilding. I test drove the car at highway speeds and with the cowl vents taped, I was able to received hot air.
Has anyone experienced a temperature difference between the driver's and passenger's side as recorded. If you did, what was the cause?
I will appreciate help. I have tested both servo motors inside the cabin and both are working normally. I have taped the fresh air cowl vents and I removed the fresh air servo motor for rebuilding.
I hope that someone on our site will see the extent of work that I performed and the information I have provided and lend assistance. We have experts on our site.
Has anyone experienced what I am experiencing? Why the temperature variance between sides?
Please recognize my efforts and help.
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Old 01-13-2019, 06:33 PM
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mike cap
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Originally Posted by Twilightblue28A View Post
FYI: I operated the temperature control repeatedly to ensure that both Motors inside my car weren't operating intermittently. They both work consistently.
Tore is right of course from his previous post. But continuing on the cave man route under duress.....

if your sure you’re getting luke warm air to all three outlets on the drivers side then there’s an issue between the hot engine and your outlets. Possibly a disconnected or torn heat exchanger hose?
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Old 01-13-2019, 06:47 PM
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Originally Posted by mike cap View Post


Tore is right of course from his previous post. But continuing on the cave man route under duress.....

if your sure you’re getting luke warm air to all three outlets on the drivers side then there’s an issue between the hot engine and your outlets. Possibly a disconnected or torn heat exchanger hose?
Mike,

I tested the servo motors inside my car and posted photographs of the damper positions when heat was called for and when heat was not called for. The photographs I took are clear. I also recorded temperatures of the driver and passenger heat tubes as well as all of the vents using a commercial thermometer. Please reread the information, photographs and the temperatures recorded. I have provided empirical information. You have also not referred to the correct information to quote me properly.
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