DIY: How to fix air blend door MK4 TDI no cabin heat problem

swetbak

Veteran Member
Joined
Jan 7, 2015
Location
Ft. Myers, FL
TDI
01 Jetta GLS, 03 Jetta Wagon, 2010 335d
My A/C mostly blows out of one upper vent. Very little out of the rest.
Also, all the vents seem to be blowing no matter what the dial is set (upper, lower, defrost), but the majority goes to where the dial is set.
Is this air blend door my problem?
 

Jesse_Boyer

Veteran Member
Joined
Aug 16, 2007
Location
Sioux Falls, SD
TDI
I'm all out...
I concur, the arm that moves the blend door likes to fall off on mine. I removed the console to make it easier to snap back in (but it's still a real pain). Do not be fooled by the temperature knob: when the arm falls down, the knob feels exactly the same. The same amount drag etc.

IIRC you can acess the arm by removing a small kickpanel on the driver side footwell, and you can stick your hand up there to find it--it helps to feel around while rotating the temp knob. The Bentley is kinda helpful here also, in letting you know where it is and how to get to it.
Definitely feels about the same, yes.

My A/C mostly blows out of one upper vent. Very little out of the rest.
Also, all the vents seem to be blowing no matter what the dial is set (upper, lower, defrost), but the majority goes to where the dial is set.
Is this air blend door my problem?
The way I addressed this in an emergency situation (friend of a friend, wanted it working) was to use a small piece of 3/4" or 1" PVC (can't remember which.) You cut a small cylinder and use the PVC as a brace/spacer to stop the arm from coming out. The PVC will fit between the lower plastic ductwork and the arm itself, keeping the arm in place.. Don't make the PVC TOO tall or it'll create too much force on the arm making it hard to turn. Take your time, get the spacer the proper length, and it seems to address the problem.

Your results may vary
 

fruitcakesa

Top Post Dawg
Joined
Feb 18, 2007
Location
Vermont
TDI
04 jetta 5 spd wagon
Mods:I am moving this to 101 for more exposure.
I have everything out of the way as per Shizzell except for the vent casing.
Is it me or is getting the vent casing out of the way a real PITA?
I can't seem to locate a way to access it so I can move it.
Is it secured with fasteners or clipped to other parts?
I am practicing this procedure on the parts car before tackling it for real on the 04. ;)
 
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jimbote

Certified Volkswagen Nut
Joined
Jul 10, 2006
Location
spiral arm, milky way (aka central NC)
TDI
Tacoma 4x4 converted to TDI
Mods:I am moving this to 101 for more exposure.
I have everything out of the way as per Shizzell except for the vent casing.
Is it me or is getting the vent casing out of the way a real PITA?
I can't seem to locate a way to access it so I can move it.
Is it secured with fasteners or clipped to other parts?
I am practicing this procedure on the parts car before tackling it for real on the 04. ;)
one screw on either side, boss through a tab at the top and a "J" hook at the bottom.... it can be a PIA if you let it but if you study it carefully and apply patience it comes right off and actually seems to go back together easier than it comes apart
 

Estergard87

Veteran Member
Joined
Sep 11, 2012
Location
USA
TDI
1999.5 Jetta
one screw on either side, boss through a tab at the top and a "J" hook at the bottom.... it can be a PIA if you let it but if you study it carefully and apply patience it comes right off and actually seems to go back together easier than it comes apart
The screws hold the back of the casing on, no? I think the front can be removed without removing the screws.

You can just pull the tabs apart to remove the front casing. There's one in the middle of the bottom, and then they're symmetrical as they go up. I think there was 5 total, maybe 7.
 

jimbote

Certified Volkswagen Nut
Joined
Jul 10, 2006
Location
spiral arm, milky way (aka central NC)
TDI
Tacoma 4x4 converted to TDI
The screws hold the back of the casing on, no? I think the front can be removed without removing the screws.
You can just pull the tabs apart to remove the front casing. There's one in the middle of the bottom, and then they're symmetrical as they go up. I think there was 5 total, maybe 7.
they hold the front plenum on .... the shortcut method only requires removal of the front air plenum
 

UhOh

Top Post Dawg
Joined
Dec 24, 2014
Location
PNW
TDI
2000 & 2003 Golf GLS
I'm going to start work on replacing a heater core in the wife's car and figure that I'll take the opportunity to re-work the blend door. I have a couple of questions:

1) Is it necessary to install strips of sealing foam around the edges of the door (after the ducting tape is installed)? I've read of folks saying to do this and then here no mention of needing to do it. If it's best to use it then what kind is best? (would hate to have this dislodge and jam the door)

2) Are there any downsides with going with the ducting tape? The holes in the door and the use of foam stock would seem to suggest a need to have a little bit of air passage even when closed(?).

NOTE: I know which tape to use, just not sure what the proper term is for it.
 

UhOh

Top Post Dawg
Joined
Dec 24, 2014
Location
PNW
TDI
2000 & 2003 Golf GLS
Out of curiosity, do properly functioning blend doors (foam still good) always allow air to pass even if you have the fan turned off?

The foam on the blend door for my wife's car look like new, yet one cannot completely disable air flow into the car.
 

Dylly

Well-known member
Joined
Jun 13, 2015
Location
Saskatoon, Saskatchewan, Canada
TDI
2005 VW Golf TDI
WAK,
Before you assume its the solely foam related, make sure your temperature lever arm is properly rotating the doors. These fail from time to time and it causes the temps to behave like you're experiencing.
Watch this:
https://www.youtube.com/watch?v=6U9ZdkAjdhQ
Does yours behave similarly? If its spreading apart like the video shows, its likely not turning the doors like it should. If so, report back and I'll give you a little shortcut on fixing this... :)
I feel like this is the problem I'm having. I haven't got right into it yet, I don't have foam coming out of anywhere on my 2005 Golf and I can get the air directed wherever I want it. Over the past week I've only got it to flip over to heat once in the morning and it seemed like it did it with the fan on high (probably a coincidence). Does your shortcut apply to my problem?
 

schwechel

Veteran Member
Joined
Jun 22, 2005
Location
Slinger, WI
TDI
2003 Jetta, Galactic Blue
I'm currently in the middle of this fix as well. I've had some foam coming out of the vents recently and just lost control of my hot/cold air mix. I've taken most of the dash apart in hopes of being able to do the "shortcut" method detailed in this post. A few plastic tabs have met their end, but not too bad so far. I'm leaning towards just doing the tape and no foam, but we'll see when I get in there. I'll try to take some pictures and post what experience.
 

schwechel

Veteran Member
Joined
Jun 22, 2005
Location
Slinger, WI
TDI
2003 Jetta, Galactic Blue
I tore everything apart and my foam is just fine. Here is a video of what I have. Also shows what should be there for anyone who is curious. Any ideas on where else to look for foam coming out of the top vents?

https://youtu.be/TLsl2CjCbLA
 
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fruitcakesa

Top Post Dawg
Joined
Feb 18, 2007
Location
Vermont
TDI
04 jetta 5 spd wagon
This was the ticket.
I popped the bottom tab and was able to grab the casing and simply pull it out and down.
Jimbote: Reinstall was easier than removal.
In fact this was the easiest part of the process.
The stripping and replacement of the dash/console/glovebox components is much more labor intensive.
I will do this next for real on the 04.
The screws hold the back of the casing on, no? I think the front can be removed without removing the screws.
You can just pull the tabs apart to remove the front casing. There's one in the middle of the bottom, and then they're symmetrical as they go up. I think there was 5 total, maybe 7.
 

Soupinmycoupe

Veteran Member
Joined
Feb 10, 2012
Location
HELLA NorCal
TDI
Manual ALH wagons.
I did the hvac tape mod when I replaced my leaky heater core. The foam got soaked with g12 so I used solvent and cleaned it all off. No more foam flying around while driving and the smell of glycerol in the cabin. Great mod if you have the time.
 

psulik1

Active member
Joined
Aug 24, 2014
Location
Chicago
TDI
2003 Jetta GLS
I know there was some debate about the FOAM v. tape, I used the HVAC tape and it worked fine, HEAT HEAT HEAT. Maybe with the FOAM you get a better seal but **** man for the work I did ( pain in the ass but not bad ) and the tape I used the heat was more than enough. Works just fine, Chicago winters.....
 

JETaah

Vendor , w/Business number
Joined
Jan 18, 2001
Location
mi 48836
TDI
96 B4V, 1999.5 jettaIV,2005 BEW Beetle
The longevity of this fix is more about the adhesive than the blocking material....how well it can hang on to the materials in the temperature extremes. If you could apply the blocking material from the opposite side of the door it would be more secure. It would be pushed against the door with the air flow.
I did it anyway using the aluminum backed 1/8 foam pipe wrap tape. We shall see.

What is the longest that this has worked for anyone so far?
 

tdidieselbobny

Top Post Dawg
Joined
Apr 4, 2005
Location
Stafford,NY (WNY)
TDI
'03 Galactic Blue Jetta TDI, '15 Silk Blue Golf Sportwagen TDI
Did the blend doors on my son's '01 Jetta today. Not too bad,found a sh*tload of broken plastic pieces when taking everything apart-a few I caused,the rest was done before our ownership. I ended up breaking the big tab on bottom of blend door cover. I was able to do it without unplugging the radio,except for antenna connection. Both blend doors were PERFECTLY clean. I used HVAC foil tape to cover both doors. The 2 screws on the blend door cover are 6mm hex,but I had a long enough screwdriver to get them that way.I used one of those grabber thingys to get the screw back in hole,but the plastic ear on the right side of cover ended up breaking:eek:...to solve the broken tab on bottom,I drilled a hole through cover and box,then used a ziptie to fasten it-worked pretty good. I took car down road and started to get heat in about 1-1/2 miles,way better than the zero heat before I did the doors. Son is REALLY happy now..... the PO took the car to a garage last March w/ no heat complaint-they changed the t-stat and coolant, so I don't know if he realized it still had no heat or not-we bought the car in June, the A/C worked good,but the heat sucked in the fall,but no foam was coming out of vents.
 

Golf3D

Well-known member
Joined
Sep 13, 2011
Location
Central Florida
TDI
2000 Golf 2dr 5spd
When I got my 2000 Golf several years ago I replaced the A/C compressor and several related components hoping it would keep the cabin cold in the hot Florida weather. Yet with perfect high and low side pressures, tinted windows and a silly beige dash cover it never got better than marginally cool. And even with mild winters here, the heat was useless.

After reading this and many other threads about the vent door foam I finally took the plunge this week and had Scott Krout in Jacksonville perform the repair. He disassembled the dash, removed the remaining foam, cleaned everything out and recovered the doors with specialized tape for A/C systems. Now I have REALLY COLD air coming out of the correct vents using the rotary control and the heat works too! With another brutal Florida summer coming up I'm happy I spent the money and this is fixed now.

So if you have weak A/C from random vents, no heat and bits of foam blowing on you, it seems you can NEVER achieve proper cooling and heating unless you or a guru does this repair!
 

Aquaticmind

Veteran Member
Joined
Apr 17, 2009
Location
Wheeling, WV via Athens Georgia via, Bainbridge Is
TDI
2003 Jetta Wagon
Hi folks,

I was driving to the beach today and suddenly my vent started blowing hot air instead of cool air with no change when I moved the hot/cold air dial (the AC was off, but it had been working earlier). I haven't seen or had any issues with the vents blowing foam, but I need to find a way to stop the hot air so I can use my AC and not roast. The black interior and a hot Georgia summer demands AC.

Does it sound to you folks like I have an issues with the foam on the blend door or is it possible that the cable that controls the hot / cold mix for the air has just become disconnect. If it's the later, is there fix?

Thanks
~James
 

JETaah

Vendor , w/Business number
Joined
Jan 18, 2001
Location
mi 48836
TDI
96 B4V, 1999.5 jettaIV,2005 BEW Beetle
Are the radiator fans turning when the A/C is switched ON?
Is the center of the compressor pulley turning?
Could be unrelated to the blend door if it happened all of a sudden.
 

Aquaticmind

Veteran Member
Joined
Apr 17, 2009
Location
Wheeling, WV via Athens Georgia via, Bainbridge Is
TDI
2003 Jetta Wagon
I haven't checked the radiator fan yet, but I replaced my fans last summer. What was really striking was that it didn't make a difference at all where I had the air temp setting, and it was a cool night so without the AC evening being on, I should have been able to cool night air through the vents.
 

Perfectreign

Veteran Member
Joined
Jul 20, 2013
Location
Los Angeles
TDI
2000 Jetta GLS 5-speed
So, I decided enough was enough and took the plunge yesterday. Fall is the hottest time of the year for us in LA, so I've been driving my Avalanche since the Jetta has no cooling ability.
I almost took the plunge on a Passat lease yesterday. Even cheaper than the 2015 lease my beautiful young bride has at $98/month.



However, I thought let's get it done. The tutorial was fantastic. One thing I wanted to comment on, though. Need to have small hands. The space in there is very tight.



Using some aluminum tape and blindly trying to stick my hand through the tiny door, I was able to cover two of the doors. I know there's supposed to be three, but couldn't find the third.





...with the door going to the floor.

IMG]http://gdurl.com/MHAf[/IMG]

One thing I noticed was the the prior owner had a dentist appointment in September 9, 2002. I hope it went well. I found this card from a dentist in Deepinharta Texas with an appointment date of 2002. It was wedged in behind the air controls and up against the plastic panel which gains access to the blend door. The appointment was for a Gaylen (or Gaylan).




So, thank you to the OP and the rest for the great instructions. I now have cold air and will have heat if it ever gets cold.
 
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PaCrazyLady

New member
Joined
Sep 30, 2016
Location
Pennsylvania
TDI
1999.5 Jetta
I'll be attempting this fix tomorrow on my 99.5 Jetta. While I'm not a mechanic, I hope my perserverance pays off in what could be a costly repair if shop does it. My question is, after reading some posts and other articles and watching YouTube, there was some indication that the cover over the blend door can pop off?? Am I understanding that correctly?
Also, is this a multi day job or can I tackle it in 6-8 hours?
I've only had the car a couple weeks and have no service history on it, so I'm trying to show it some TLC in hopes that it'll last me another 60-100k miles.

Thanks
PaCrazyLady
 

BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
I'll be attempting this fix tomorrow on my 99.5 Jetta. While I'm not a mechanic, .......................................
PaCrazyLady
That might be good, mechanics hate this job (a close second to electrical issues).
I've maintained and repaired my own vehicles for 40 years, also Not A Mechanic. I would give myself 2 or 3 days for working out and resolving various roadblocks you will encounter. The 3rd time you pull the HVAC unit it will take 3.5-5 hours. The first time will be closer to 10.
Your best weapons are patience and resourcefulness. Don't forget to pull the negative battery cable before starting.
 
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Perfectreign

Veteran Member
Joined
Jul 20, 2013
Location
Los Angeles
TDI
2000 Jetta GLS 5-speed
My question is, after reading some posts and other articles and watching YouTube, there was some indication that the cover over the blend door can pop off?? Am I understanding that correctly?
Also, is this a multi day job or can I tackle it in 6-8 hours?
I did mine in about four. The blend door cover literally pops off with tabs. You just need to have a firm grip and pull, realizing there's about eight tabs holding the door in
 
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