2002 Eurovan, A/c vents roar when pressing the gas

[lukeborn]

For about a year now my ev gls dash vents roar when pushing the gas,ex when speeding up. The outer vents appear unaffected, the center ones not only roar but also stop working like a flap inside is closing. I have attempted to find vac leak but I'm now at a loss. Also the floor vents seem unaffected, as do the rear vents. Any help is appreciated. Thank you in advance.

[gti_matt]

I think you're on the right track with a vacuum problem but I have no idea where to specifically start on that.

[Euro2003]

I could be wrong, but I believe there was a thread long ago about a flap not functioning due to the foam on the flap controlling the air flow coming off. The repair was something to do with changing the flap somehow. Sorry that's all I recall about it. Try to find that thread.

[vwbugstuff]

Any updates on this? I'm having similar issue with our '03.

[lukeborn]

I finally had a second to look at my repair records, the thing that sticks out to me is that about the time this all started I had the transmission replaced... I wonder if there was a vacuum house on that. It does seem to shift violently sometimes although I've heard this can be somewhat normal for the poorly designed transmission.

About the foam on the flap, I'm almost sure that is gone over the past couple years I have had random foam flakes fly out the dash and defrost vents, almost blinding me at times, but I'm not sure how the engine stress would be affecting this because of that. I've started manually putting the a/c on floor and dash... It really only makes the dash problem less noticeable. I really want to find this so if anyone figures it out I really want to know what they find out.

Sent from my Slider SL101 using Tapatalk 2

[gti_matt]

I could envision the lack of foam not *sealing* the diverter flap but causing the roaring I'm having trouble envisioning that, especially since it does it on acceleration and not on deceleration. A properly operating flap minus foam would be consistently failing to direct airflow correctly at all times regardless of acceleration/deceleration. I would still be looking for a vacuum leak or disconnected hose somewhere but it's all probably a matter of climbing around under the hood real good with a flashlight.

[Bubbleboy]

This is definitely a vacuum problem. Took mine to the dealership and they repaired a line under the hood. Which one...sorry, couldn't tell you.

[vwbugstuff]

This is definitely a vacuum problem. Took mine to the dealership and they repaired a line under the hood. Which one...sorry, couldn't tell you.

Any chance you could find out - either from the work order or the technician? That would be most helpful.

[lukeborn]

I'm sure it's not right but I followed all of the vacuum hoses under the hood by following the diagram near the radiator found two leaks, in fact one hose fell off altogether... Took it out for a drive and it was still messed up. So I removed the three center vents with a small flat screwdriver, removed the two Phillips head screws, pulled the vent out, removed the next deeper piece, then I had access to the offending flap, after some persuasion I removed it. Strange all functions seem to still work, I'm not sure what it did but now bye bye roar at least until someone finds a permanent fix. Also I did trace the vacuum line to the middle post on a bright red control module under the passenger dash, I wonder if maybe this box is to blame, the left hose goes right to the problem spot.

This post should still be considered open since this isn't exactly the answer I was hoping for.

Other things to note: this van does have a problem keeping a battery charge, AutoZone verified the battery is not the offender, O'Rielys has replaced the alternator 4 times in the last two years... Could whatever is causing this electrical problem be related? That box does have wires running to it.

Sent from my Slider SL101 using Tapatalk 2

[vwbugstuff]

Any updates???

[Dominicdrl]

Just took care of this on our 2000 MV....
For some reason, when you step on the gas when the climate control is on "AUTO", the climate computer shifts into recirculate mode. The vacuum motor that controls the recirculation flap does not work on my van. When the computer tries to activate this valve, it leaks. That doesn't allow sufficient vacuum to keep the flap to the center dash vents open, hence the loss of air flow and extra noise.
This vacuum motor (part # 7D1820625) is in the far right hand side of the air distribution housing that contains the fresh air fan, etc., and is accessible from the passenger side. There is a removable panel under the passenger air bag, that allows you to reach up to the vacuum motor.
I haven't pulled the vacuum motor yet - it is held by two screws in a really tight spot. Until I get a chance, I pulled the vacuum hose (Black with green stripe) off the vacuum valve rail (N53 in the Bentley - bright red box) and put a plugged piece of hose on the rail. I don't have a recirculate mode, but I also don't have my wife asking me what the heck is wrong with the air conditioning.
As I said above, this only happened when the climatronic was in Auto mode, or the recirculate feature was turned on. Can anyone explain why the computer would want to recirculate airflow when accelerating?

DanD
2000 MV JAVWOK2
Peoria, IL

[mukesh132]

its the Heater/AC Flap Actuator , i have he same problem, the whole front dashboard needs to be taken off and new actuator replaced,

i have the problem for my 2000 eurovan , part hard to find, even from the dealer, the mechanic rigged the hoses so that my ac vents will not have the problem, the a/c neds to be put in recirculation mode, i am still looking for the part,

[vwbugstuff]

Ok guys, this "vent roaring" thing has been driving me crazy since the end of May when we went on vacation. It's finally cooled down enough for me to find the time to tear into this.

Going by previous posts, I tested the blend door actuator and it seemed to work fine. Next, I tested the vacuum rail (the red module under the dash) and it appeared to work fine. Then I tested the vacuum actuator that actually controls the center vent doors and it also was working.

So, I figured that since everything was working correctly (except under acceleration) that there was not enough vacuum coming from the engine to operate the components correctly.

The vacuum line that controls everything goes thru the middle of the firewall between two hoses. I had already replaced it, as well as some of the other vac hoses that branch off of the brake booster hose. I also replaced the blue/black check valve. All of this and the vents still roared!!!

Other folks have had problems with the brake booster hose cracking - I inspected mine and it looks ok. But, other than blowing thru it, I really have no way to test the built-in check valve.

So, to test the interior vent system, I unplugged the vac hose from the firewall side of the blue/black check valve and plugged the check valve. I re-routed the vac hose to the round vac reservoir (a known good vac source) and went for another test drive. VIOLA!!! Everything worked!!! On recirc and fresh. No roaring and the vents and blend door all operated normally!!!

So, I'm assuming that the check valve in the brake booster hose is bad and I've ordered a new one. You have to order the whole asembly as the check valve isn't available by itself. I'm hoping that this also cures the brake pedal going to the flooor issue that myself and others have had upon cold start-up with the Climatronic on.

Fingers crossed, I'll post an update when the part arrives.

[jajerden]

Ok guys, this "vent roaring" thing has been driving me crazy since the end of May when we went on vacation. It's finally cooled down enough for me to find the time to tear into this.

Going by previous posts, I tested the blend door actuator and it seemed to work fine. Next, I tested the vacuum rail (the red module under the dash) and it appeared to work fine. Then I tested the vacuum actuator that actually controls the center vent doors and it also was working.

So, I figured that since everything was working correctly (except under acceleration) that there was not enough vacuum coming from the engine to operate the components correctly.

The vacuum line that controls everything goes thru the middle of the firewall between two hoses. I had already replaced it, as well as some of the other vac hoses that branch off of the brake booster hose. I also replaced the blue/black check valve. All of this and the vents still roared!!!

Other folks have had problems with the brake booster hose cracking - I inspected mine and it looks ok. But, other than blowing thru it, I really have no way to test the built-in check valve.

So, to test the interior vent system, I unplugged the vac hose from the firewall side of the blue/black check valve and plugged the check valve. I re-routed the vac hose to the round vac reservoir (a known good vac source) and went for another test drive. VIOLA!!! Everything worked!!! On recirc and fresh. No roaring and the vents and blend door all operated normally!!!

So, I'm assuming that the check valve in the brake booster hose is bad and I've ordered a new one. You have to order the whole asembly as the check valve isn't available by itself. I'm hoping that this also cures the brake pedal going to the flooor issue that myself and others have had upon cold start-up with the Climatronic on.

Fingers crossed, I'll post an update when the part arrives.

Thanks for the info, my 2000 Eurovan is doing the same thing. Have you had a chance to install the the new check on the Booster yet? I have replaced most of the vacuum hose's also and still the same issue?
Jay

[vwbugstuff]

New part arrives Monday - I'll post my results Monday night.

[jajerden]

Any luck on the hose & check valve ?

[vwbugstuff]

Well guys, it's back to square one. I replaced the booster hose and the vents still cut out. On the positive side, my brakes feel better.

I don't understand why the vent system doesn't work when hooked up correctly, but when I hook it up to another vacuum source it works.

I guess it's time for a trip to the dealership.....

[jajerden]

The recirculation diaphragm was bad . Located on the passenger side of the air box. You must remove the knee bar on right side of the dash to have better access. The part number for 2000
model is 191-820-677-B .... They run about 250.00 bucks but if you want the air to work properly if more than worth it. You must have torque T-20 socket to remove and install the screws......

[vwbugstuff]

The recirculation diaphragm was bad . Located on the passenger side of the air box. You must remove the knee bar on right side of the dash to have better access. The part number for 2000
model is 191-820-677-B .... They run about 250.00 bucks but if you want the air to work properly if more than worth it. You must have torque T-20 socket to remove and install the screws......

Is there any way to test it once you remove it?

[jajerden]

About the only way is compress the plunger and plug the vacuum port on the accuator . Mine would only hold for a few seconds and the plunger would slowly leak down . The hardest part of the hole deal was putting the console pieces back.

[vwbugstuff]

UPDATE: Two issues have finally been fixed - this and the lack of heat issue that I was having.

Parts used for the repairs:

Vacuum Solenoid Valve - Part #028-906-283 - Affects the vacuum to the blend doors in the dash. The blend door actuators were working correctly.

Vacuum Heater Valve - Part #1J0-819-809 - Controls coolant flow. Would not hold vacuum so it stayed open and would not allow coolant to reach operating temp.

Fans not operating correctly - Part #701-959-263D - Both fan resistors corroded and failing.

All is well with my HVAC again.