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Discussion Starter #1
It was suggested someone should open up an AAV to see what is inside. Well, here you are.

There appeared to be four rivet heads so I ground those off. Then I ground off the crimped perimeter and used a small punch on the rivets to separate the two halfs. (Note that this was a long dead AAV.) Once inside the movable vane is obvious. There is a small spring to pull the AAV 'closed'. There is an arm at the bottom that rests against some sort of lever attached to the electrical connection. Unfortunately applying 12V to the electrical terminals did nothing so I am not sure how that bit is supposed to operate. I am guessing it must move sideways to act on the arm of the movable vane. I put the half with the electrical piece in the freezer to see if it moves in the direction that would open the vane when cold.

Next examine the adjuster nut. Loosening it only allows a wee bit of adjustment of the moveable vane's pivot. I wouldn't have a lot of hope that fiddling with it will make any noticeable difference in the AAV's operation.
 

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Discussion Starter #2 (Edited)
OK, after 10 minutes in the freezer the lever on the electrical bit did move laterally. Remember that this was a not functioning well AAV - I suspect that a good AAV would have more movement to open the vane when cold.

Oh, the electrical bit appears to be secured in the housing by a tiny roll pin. I was hoping it was a tiny screw but no luck.

I have seen automotive web sites offering 'rebuilt' AAV's. I do not see how they could get inside in a non-destructive way. Perhaps the electrical bit might be replaceable to restore operation?
 

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awesome!

The strip is bi-metallic. One side contracts and expands faster than the other causing it to bend depending on temperature.

The electrical connection is for a small coil that heats up the strip on start-up to help the valve close faster as the engine heats up without purely relying on ambient engine heat.
 

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Discussion Starter #4
I wonder what makes them stop working? I know that electrical bits can fail & thus the heating element could stop working but wouldn't the bi-metal strip still work with ambient heat (albeit slower)?

The dead one I disected showed almost no movement between 10F & 150F (perhaps 1/8" - 3/16" at the end of the strip where it'd contact the arm on the movable vane).

I also noted a fair amount of gunky residue inside. I didn't clean it before disassembly but it is likely I did before tossing it into the box of dead AAV's in my garage. And from looking at it apart, I doubt that spraying solvent into it or soaking it in soapy water would really have much affect on anything inside - it seems well sealed (so how does it get gunky though...?).
 

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I wonder what makes them stop working?
I'm happy to see there's still guys out there that want to know how things work.

Those bi-metal strips just have so many stretches in them. Plus the metals transfer electrons back and forth so they loose their uniqueness. They just have so much life in them.

I also see a return spring that probably looses it's action.

Thanks for the pictures.
 

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This is my AAV after coming out of the freezer. It was in there for a good 20-30 min and the body was ice cold. There was no change in the opening from removing it off the car and after taking it out of the freezer.

The car was a little hard to start, but finally started. After up to full temperature, i removed the AAV and it was shut completely. Should I bother with the adjuster nut or just buy a new one? I have a feeling that it should be more open when cold.
 

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Discussion Starter #7
IME that 'adjuster' nut does little to nothing. The bi-metal strip seems to lose its ability to move and then the vane does not change position as intended.

Either get a new one ($$) or fabricate a manual version ($) - info about the manual version is in the FAQ thread.
 

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IME that 'adjuster' nut does little to nothing. The bi-metal strip seems to lose its ability to move and then the vane does not change position as intended.

Either get a new one ($$) or fabricate a manual version ($) - info about the manual version is in the FAQ thread.
Thanks Eric, I think I'll buy a new one. Rockauto seems to have them for a reasonable price, unlike the usual Alfa vendors.

I tried bypassing it completely and the idle was pretty erratic; it would hunt up and down constantly.
 

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Although new Bosch 0280140140 AAV's are no longer available, I have heard from more than one reliable source that the Bosch 0280140125, which is still available new today (and the one being sold by RockAuto), is the closest thing to the stock/original 0280140140 out there.

I am certainly interested to hear how the new 0280140125's, recently purchased by several BB members, performed.
 

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I would be interested to know if there was an alternative other than converting to manual operation.
 

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Discussion Starter #13
New replacements seem to be available. They are pricey so us frugal types (OK, cheapskates...) use a manual version. You just have to remember the manual version is self-closing (you have to close it yourself).
 

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Cheapskates?

How dare you!!

Seriously, for many of us the workings is the fun. and rebuilding is a form of recycling. I attempted to dis assemble a non working AAV but was unable to get it open. I opted to purchase from RockAuto for $75.

The water pump on our spider is making noise? not sure from where. Does anybody rebuild these water pumps?

Cheap can be fun
 

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Great post, Eric. Good detail on the mysterious failing AAV... and yes the bimetallic strips work and work, and then fail after years of cycling. It's what used to power automatic chokes on American carbs years back. I replaced many of them.

Mike has a manual AAV that came on his '86, thanks to Greg Gordon:

Silicone Hose Kits
 

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How dare you!!


The water pump on our spider is making noise? not sure from where. Does anybody rebuild these water pumps?

Cheap can be fun
This isn't one of those spots to go cheep, and I'm a real yankee cheapskate that will straighten bent nails. Head gaskets are just too muck work and $$ to go on the cheap with the water pump.
 

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Can someone take a photo of their NEW AAV's opening when cold? I would like to compare that to the current opening of mine when cold. I bet it's more than the tiny triangle of an opening that I posted a few above.
 
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