Climate control vacuum issue ( That old topic)

[BottFodder]

Nothing new here. I have to classic "air goes to windscreen" issue on my S1 Berlina which has climate control.

Its been like this for a year or two but recently I replaced the radiator and although that worked OK, all of a sudden my heater is working "poorly". It hasn't stopped working completely but I can't get the interior really warm and toasty. Probably up to about 18C. It also takes about 15 minutes to get there which is PITA in Canberra.

I decided to do some research and figure the problem out. I have read as many articles as I could find about the issue and seen posts about vacuum solenoids, check valves and actuator assemblies.

I got stuck into it yesterday and noticed that if I go from full cold to full hot, the water valve in the engine bay never changes state (ie from on to off) so I pulled out the solenoid pack and had a look. All the solenoids are functional and using a stethoscope (the ones you use to find vacuum leaks around manifolds) I couldn't find a leak anywhere. All the actuators work too. The system does change from face to demist etc as required.

Next thing I tried was to bypass the vacuum reservoir. Its pretty simple as the reservoir has a large(ish) inlet from the manifold and a smaller one which heads to the solenoid pack. You just stuff the outlet into the inlet. As soon as I did this, everything including the water valve now works! I noticed that although the vacuum from the engine is reasonably strong, the outlet side is weak as (piss weak?).

My question is... how does a small plastic tank "Fail"? I suspect the problem has been simply not enough vacuum emerging from the reservoir tank. I'll probably just buy another one (just to see) but I'm still unsure as to why this would happen.

Anyone have any suggestions? What's actually inside the tank. Bypassing it permanently is probably not an option as I will now have valves that change position constantly depending on throttle position.

[Calaber]

As it's just a plastic tank, the obvious thing would be to pull it out and check for cracks or blockage of the inlet and outlet before outlaying for a new one. I haven't looked at mine but I assume it's just an empty container with no internal components. My shop manual doesn't indicate any valves or other parts inside it.

[BottFodder]

Thanks for the reply. I had a good look at it while it was out of the dash but could find any cracks/leaks. Might see if I can find a cheap one from a wrecker before I start pulling it apart. Interesting that it is made by Eaton. Doubt if it comes out of the same factory as the Roadranger.

[adsvz]

Hey Guys!

Can someone put up some photos soo i can see what your looking at?? I have kinda the same problem!!

Cheeeeriio

[D3CID3R]

i have the same issue... never thought of the vacuum tank... thx for the heads up mate

[BottFodder]

Haven't got any photos but its absolutely simple to get at.

1. remove the glove box, release the 2 rubber stops (on on each side), drop the glove box down and then it just slips out.
2. remove the plastic dress cover that is over the blower motor. Its just held on with spring type clips.
3. the vacuum tank is on the left end of the blower assy. Stick your head under the blower and you will see a single screw that holds the tank against the blower. Take the screw out, push the bottom of the tank to the left and it falls out into your hand.

Installation is just the reverse.

I'd be really interested if anyone else can shed light on this issue. The tank seems so simple that it almost "can't be" a problem

BF

[Calaber]

Haven't got any photos but its absolutely simple to get at.

1. remove the glove box, release the 2 rubber stops (on on each side), drop the glove box down and then it just slips out.
2. remove the plastic dress cover that is over the blower motor. Its just held on with spring type clips.
3. the vacuum tank is on the left end of the blower assy. Stick your head under the blower and you will see a single screw that holds the tank against the blower. Take the screw out, push the bottom of the tank to the left and it falls out into your hand.

Installation is just the reverse.

I'd be really interested if anyone else can shed light on this issue. The tank seems so simple that it almost "can't be" a problem

BF

It would be simple to conduct a pressure test to detect any leaks in the tank. Block one of the inlet/outlet ports. Using a tyre pump, with the flexible pipe slipped over the remaining port and taped into place with duct tape, hold the tank underwater and operate the pump. Any leaks through minor cracks or holes will become obvious very quickly.

I used this method years ago to detect a leak in a heater core. Worked a treat.