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Discussion Starter #1
Getting this noise coming from the vacuum distribution behind my glove box .
Not exactly sure what this part is called so if anyone knows please let me know .
It’s getting stuck making lots of noise thinking is a vacuum line issue.
It’s causing my heat to turn off and on without any control over it, got a mind of its own.
Any ideas or info please let me know I appreciate it in advanced,
EF010A2D-D9FD-41D7-A801-D0E48D0AEAA4.jpeg
I’m
Thanks
 

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2008 E320 OM642 Bluetec1992 300D 2.5 Turbo (Sold @ 248k running strong), 1985 240D (sold)
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That is a "Climate Control Vacuum Power Changeover Valve". It directs vacuum to the vacuum pods under the dash. If it leaks or fails you won't have control of the heat and AC doors.
Not a cheap part. You'll need one specific to your car, but the same part number was used in many different models. Here's an example:
Eventually you'll find the vacuum pods under the dash that open and close the heater and AC mixing doors and vent shutoffs will need to be repaired or replaced too. They're just a rubber diaphragm type vacuum servo and crack or tear with age.
 

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Discussion Starter #4
Thanks do you know if there can be anything else that can cause it to fail or can I repair it
 

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2008 E320 OM642 Bluetec1992 300D 2.5 Turbo (Sold @ 248k running strong), 1985 240D (sold)
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You don't tell us the year and chassis of your car. I'm guessing a 124 from the valve in the picture.
What kind of a noise is it making? What are the symptoms i.e. no center vent air flow, no heat, no side vent air?
I used the DIY below to repair mine once. The pictures are a bit blurry, but you can read the directions.
 

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Discussion Starter #6
You don't tell us the year and chassis of your car. I'm guessing a 124 from the valve in the picture.
What kind of a noise is it making? What are the symptoms i.e. no center vent air flow, no heat, no side vent air?
I used the DIY below to repair mine once. The pictures are a bit blurry, but you can read the directions.
 

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Discussion Starter #7
ITS A 92 300D thanks for the info I really appreciate it going to take And diagnose it
 

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2008 E320 OM642 Bluetec1992 300D 2.5 Turbo (Sold @ 248k running strong), 1985 240D (sold)
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1992 300D - Great car! I put almost 350k miles on mine. Engine was still running strong with only a precautionary timing chain replacement at 150k. Trans and diff were approaching end of life though. Even with 50k mile oil change intervals they were getting "clunky" for an auditory description.
 

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2008 E320 OM642 Bluetec1992 300D 2.5 Turbo (Sold @ 248k running strong), 1985 240D (sold)
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If your vacuum pods have failed they won't hold vacuum so won't move the doors for the heat/cool air mix and direct to the various vents. You can check to see if they hold vacuum by using a Mityvac or clone from Harbor Freight from the lines at the control valve you're checking now. You can see one of the pods behind the valve in you picture. It has a pink cap and an arm coming out to a lever.
 
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