nine9six

I would agree on the noise change, unless you never knew or heard the difference!

nine9six

Please pardon my ignorance, but is this view behind the CCU unit removed?
...Some are saying under the dash, but this does not look like an under the dash photo.

TIA for any additional confirmation you may be able to provide.

P.S. Great post Andy!

pp000830

I think if you look up from under the dash you will see it. With the CCU out you can also see it through the front of the dash??

phoneyman

^ thats what it looks like to me too. Behind the radio is nothing besides wire loom from what I remember, plus half of it is over the center tunnel cover so couldnt see too much looking from under the dash.. And I've had my radio out plenty. The CCU has only been out once.

pp000830

I'm told this process works best with a good Cuban cigar.

pp000830

withdrawn

HiWind

just wondering about this some more ...

if there's a vacuum leak, then surely there wouldn't be much vacuum anywhere in the system, right?
So if you pull off any of the thin vacuum hoses and check if there's vacuum .. ie its hard to pull off and once you do there's a release etc.. then surely you don't have a leak, right?

nine9six

...I'm sure one of the gurus can chime in on what the vacuum spec (inches of mercury?) should be, plus there would need to be a tolerance assigned to that measurement as well...There's no such thing as absolutes.

So a vacuum gage or manometer may suffice for measurement purposes once the spec and tolerance is known?

bcameron59

Most of the relevant components (ie the 5 actuator diaphragms, or 4 on the RS) are downstream of a check valve and includes the vacuum reservoir, so should hold vacuum unless there is a leak. See #8, just upstream of the tee-connector #10 in Bill V's diagram in post 3 of this thread. Other stuff like gas tank, brake booster etc is isolated from the intake controls.

Shop manual says to test varioram flaps by applying vacuum tester at the fresh/engine air flap diaphragm, the easiest one to access without pulling anything apart. You need a helper for this.
- Run the engine for 20 seconds at 2500 rpm to build vacuum, then shut off ignition
- go to the engine compartment and watch while the helper turns on ignition (but without engaging starter motor)
- you should be able to see the 2 varioram flap lever arms moving
- if they don't move, check the vacuum gauge
- if you have vacuum, but flaps don't move, the vacuum control solenoid valves that feed the diaphragms may be bad, or their wiring, or the diaphragms themselves.

After the test, vacuum should measure at least 0.64 bar / 480 mm Hg and over a period of at least 3 minutes should not drop lower than 0.62 bar / 465 mm Hg (ie max drop of 0.02 bar / 15 mm Hg). If leakdown is faster than that, you have a leak and need to investigate further.

Jlaa

Sorry if I missed this earlier in this thread .... I have been trying to follow the thread. Are all five actuators the same part number Porsche 993.110.562.02 or BMW 11617786961? I've never detected any intake noise change in my own car since I bought it 30 months ago and suspect I have some similar issues. Oh how RL sends us down the slippery slope, both real and imagined!

bcameron59

993 572 077 00
- located under dash - katalog illustration 813-05, position 41
- includes the entire recirc flap unit ie the diaphragm is not sold separately

993 110 462 02 - there are 3 of them, located at:
- varioram, bottom center, katalog illustration 107-12, position 4)
- varioram, top right' katalog illustration 107-12, also position 4 (two of 'em)
- fresh/engine air flap (on blower ducting to left of fan, katalog illustration 108-12, position 6)

993 110 461 03
- upper left varioram flap, katalog illustration 107-12, position 6. Not sure why this one is different??

OverBoosted28

I think (and as Steve W earlier stated) that just like any other rubber component of our cars, they all need to be addressed, and replaced as needed. I will go through and change everything that has any of the original rubber (for the intake vacuum system). Great thread.

nine9six

Brian,
Thanks so much for your last two posts! All the info needed in a nutshell

kjr914

Those pics from X50type are directly thru the CCU dash hole from the front of the dash with the CCU removed. I took the same pics this summer when I had the CCU out to service the fan noise and clean the sliders, **** potentiometers, and the infamous MaxAC button. The first is a close up inside the dash of the actuator. The actuatorcan be barely seen at the bottom of the dash hole in the other photo where the pic is clearly from the cabin.

While I was in there, I found a resolution to the occasional "THUNK" from up front in the dash. was my fresh air (recirc) flap closing (or opening...don't remember which way it is). There is a pivot where the actuator connects to the flap, but the bolt/pivot-pin was missing, so the vacuum actuator worked, but couldn't move the flap.

I was able to get a bolt into the pivot point with some major hand yoga (one through the CCU hole, one from up under the dash. A PITA job if there ever was one! Although there is at least 1 bolt floating around in the abyss after being dropped up there... So, since I could get my hand though there, you *might* be able to see up from underneath, but the clear view is with CCU out.

Sounds like a real issue in your case. The intake noise might be "subtle" to some, but it is there (2x) and if you're paying attention should hear it. Does your fresh air/recirc button on the CCU cause a *thunk* from within the dash? If not, maybe its not actuating (thus vacuum leak).


To help determine if your actuators are good/bad, you can test the actuators by pulling off the tube to it and blowing/sucking on the tube to see the actuator move (or hear the leak). I used an old CamelBak hose to move my actuator for the fresh air/recirc to test it was working and to help line up the pivot bolt I had to replace.

pp000830

Just replaced three of the four vacuum actuators on the engine. The one under the Varioram intake manifold was removed by removing the rubber duct above the fan. Had to make a Phillips wrench by sliding a short screwdriver bit into the end of a ignition closed end box wrench a 12 point works better to orient the screwdriver bit. Takes about 30 wrench cycles to get each screw out. Used tape and a sliver of sheet metal to keep the bit in place. Hemostat very useful to remove and reinstall the screws, used rags to catch any dropped bits or screws. Very tedious but can be done removing just the actuator.Andy
PS, the replacement ones seem to have silicone diaghframs. Look to be more robust.