Air filter Thermo vacuum part

Just bought a later type oil bath filter for 'the van', the type operated by vacuum from the carb / inlet manifold. The actuator works with a hose and suck direct to it, but it doesn't work with both hoses connected and thermo unit warmed up as if fitted to engine, 30C. I'm presuming i need a new thermo/ vac unit (035-129-630-B).
£71 from a VW dealer , does anyone else flog em!. Any info appreciated

 

What does it look like? Is it the oblong plastic thing?

 

have a look on here https://thelatebay.com/index.php?threads/oil-bath-air-cleaners.73774/page-6#post-1636408
i got one from VW heritage for about £30

 

Yes, that's the one

 

^as above, might be able to get one from Heritage (although they're getting pricey). I got one for my late airbox yonks ago. They were also used on early Golfs/Polos and the like.

 

If its warm it shuts off. When its cold it should be open. That is the correct way round. By doing this it stops the hot air feed from below when it reaches 30C as designed.


At cold idle, vacuum in manifold, vacuum to flap actuator, flap to hot to stop carburettor icing.

At full throttle, no vacuum in manfold, or to flap, actuator flap to cold for efficiency.

At any time if air in intake over 30C, vacuum off through thermo switch, regardless of manifold pressure, flap to cold to stop it getting too hot.

So idling warmed up the flap will open and close periodically. Air intake duct at 30C .

At full throttle flap will be open...air intake duct cools down so flap will open immediately on idle for immediate icing prevention.

 

Thanks Mike, so with the filter off the vehicle, tubes connected with the thermo / vac unit cold , should i then be able to operate flap by sucking on the tube that would normally be connected to the carb or inlet manifold ?

 

I struggled to suck mine by mouth. In the end I used a long piece of pipe from the carb to test

Sent from my SM-G973F using Tapatalk

 

Yes, with the setup cold, it should be possible. If not, the dirt that was in the tube on the thermo vacuum switch on top of the cleaner might need cleaning out with something like petrol or white spirit.

 

You'll have to have good lungs

 

Cheers Mike, in that case i think it's knackered , but i've sourced a new one.
Phoned not so local VW dealer and he said he could get one but i'd have to actually come in and pay for it, drove all the way there today, he then informs me he can't get one, deleted in 2017, words failed me, the Muppet. As i said i've got one online from a VW independent parts place.
fitted the weighted flap assembly out of my filter and popped it into the vac one as that was pretty much shot, had to clean out base, absolutely full of clag etc, i'm going to use my top filter part, just need to drill two holes in it for the temp/vac valve, thanks for your help