I imagine this bit may be common to all of the engine covers that are combined with airbox/filter/blend mechanism. In my case it's off my 53-plate Polo BBY.

 

Little wax thermostat which pushes a linkage to rotate a blend flap selecting between 'all warmed air', 'all cold air' or anywhere in between.

 

Looks like this from the side:

 

 

Sorry about the focus, or lack of.  That's about 20mm long by 10 diameter, ballpark.

 

 

The only markings on it are here, on the end:

 

 

I'm not having a lot of luck searching for that, without so much as a manufacturer to go on.  Anyone got any ideas?

 

The airbox is only available whole, 036129607CS, as here, but I think new would be a hideous price, and secondhand it would be a gamble on whether the thermostat is any less broken than mine.

 

Trouble is, the default position when this bit isn't doing anything, is with the blend flap pulling only from the 'stove pipe' off the exhaust manifold shroud. I imagine quite a few cars with this design are running around on hot air.

 

I've just bought a 2003 poll 9n, all your posts worry me!

Haha, sorry! What engine?

1.2 12v. It's a beast alright.

Edited 7 February, 201511 yr by hutchysrs50

If anyone can think of anyone, on the whole of Briskoda or beyond, who might be able to help with sourcing one of these little darlings, please link them to here.

 

Ta

 

Humm, you and a lot of others too!  I've never managed to "fail" mine yet - keep meaning to do that.  Bring back the good old "summer"/"winter" flap that was under the control of the driver!  Are you getting pinking or what?  Have you ever filled it up with Shell Nitro+ - that engine just loves that stuff, the improvement low down torque has to be felt to be believed - if I filled wife's car up with ordinary petrol she would spot it very quickly.

No, no pinking or other overt misbehaviour, but I can't help thinking it'll be happier on cooler air.  Shame it fails this way, as it'd be a more graceful failure for most climates if it failed on full cold rather than no cold. Should be quieter/better on cold feed too, as there's various blind alleys in the airbox platickery (bypassed for warmed air) that are presumably about either sound deadening, or resonance tuning for airflow reasons?

Must check the Fabia too, as I  haven't for a year or two.

Haven't tried fancy petrol either, but I'll try it to see if I can feel the difference.

All you have to do is flip it round and put it back in, that way it jams the flap open permanently, warm air is only needed for very cold climates. Be careful of the ridiculously strong spring, I nearly lost a fingernail when it slipped on mine!

I don't want to bodge it though, I want to make it work properly.

 

It does take some careful disassembly, I agree.

Are your nails like these?:

 

Nice, blood red, no one would noticed if you smashed your nail!

I don't want to bodge it though, I want to make it work properly.

 

It does take some careful disassembly, I agree.

Are your nails like these?:

 

 

Are you suggesting that my solution is something other than a cunning improvisation based on a considered analysis of the device's necessity in our temperate climate.

 

How dare you!

 

Yes, those are my nails on a Friday evening before meeting Grayson Perry for a sweet sherry or three.

Are you suggesting that my solution is something other than a cunning improvisation based on a considered analysis of the device's necessity in our temperate climate.

 

How dare you!

 

Yes, those are my nails on a Friday evening before meeting Grayson Perry for a sweet sherry or three.

 

Err, no, but yeah, but no...

 

It's actually a neat solution, but I like to have things 'as designed', as far as economically viable.

 

Found a (NOS) thermostat on ebay last night that's a Volvo part, looks very similar, and presumably operates on a similar temperature range as it's also an airbox application.  Will see if I can fit it when it arrives in a few days.

Oh well, I hope you get somewhere with that purchase, never ventured nothing gained!

Did you try the volvo air box thermostat?

https://www.pelicanparts.com/More_Info/1266826.htm

 

I would like to try it but shipping to my location is 3 times the price of the thermostat itself!

Yes I did, I had to trim down the piston/pushrod part as it was too long, but it worked for a while.

I happened to log intake temps this summer sometime and they were higher than I was happy with, so I made a brutal adjustment with a woodscrew.

Flap now permanently in cold air only position. Better than the default failure mode of hot air only which a lot of these cars will be driving around with unknowingly.

 

On 09/02/2015 at 13:31, Wino said:

Must check the Fabia too, as I  haven't for a year or two.

 

Did this last summer I think, finally, and found it too failed. Screwed the flap directly into the cold air only position.

 

Which country are you in @yurtesen? 

@Wino I am in Finland. The intake air temp sensor reads 40C-50C normally. I am not sure if that is too high or not as I don't know what is the normal temps   At least in my case the flap seems to be stuck in the middle. Perhaps it is not the best idea to set it to cold only as temps go down to -15C where I am in winters

 

I have a Golf MK4 with BCB engine and the flap is inside the air filter box/engine cover.  I first need to find out how to remove it from there as the springs were super hard and it was very tight there.

 

So you bought a brand new volvo air box thermostat part and it failed after about a year? How can that be?

I think for Finland 40-50°C would be ideal in winter. Maybe just fit a screw like I did in summer to force it fully cold?

 

I don't know if my Volvo thermostat failed, or was just never quite optimal in terms of intake temps. I think it was similar to what you are seeing when I checked.

 

Those springs are tough to overcome, I remember!

 

@Wino I think I get 40C-50C in summer also, have to check. But I put the thermostat under hot water and it does not close the hot air flap completely. Only if I knew what the temperature should be normally...

 

From where did you get Volvo thermostat? is there a cheap way to source them? Also which model? I think 1266826 model has longer pin. (see the link below)

 

I found one cheap here:

http://www.skandix.de/de/fahrzeug-teile/motor/kraftstoffaufbereitung/einspritzanlage/leerlauf-warmlaufregelung/thermostat-warmluft-kaltluft/1668/

BUT thermostat costs 10euro and shipping costs 30euro to Finland! I think the cost is too high for a part which can fit to an envelope and this part does not seem to be available in Finland.

 

7 minutes ago, yurtesen said:

From where did you get Volvo thermostat?

 

Ebay, I can't remember the price but it was that part number you mention, maybe around 10GBP.

Yes, I had to cut the pin shorter, but it was a bit of a guess how much. I think I cut a little too much off, so the temps were higher than I was aiming for (maybe around 20°C).

Well, 20C sounds pretty good. Because the workshop manual (at least for golf mk4) says that flap opens at 10C and closes at 23C

https://workshop-manuals.com/volkswagen/golf-mk4/power_unit/4-cylinder_injection_engine_(1.4_l_and_1.6_l_engine)/mixture_preparation_system_electronic_inj.gas/checking_components/checking_intake_air_preheating/

 

By the way, at least in my car the thermostat does take in air from the top of the motor cover. There are 2 tiny holes there which put air to on top of thermostat. So thermostat works with engine bay temperature and not with intake air temperature.

If you look at the picture below, you can see there are 2 round dots which are darker than the rest, just between oil cap and 1.6 text. Those are air holes which has a pipe directly to the thermostat which controls the flap.

 

 

Interesting about the feed from the top. I think the Polo probably has the same, judging by the tube underneath the thermostat in these pictures:

 

 

 

 

Edited 3 December, 20196 yr by Wino

@Wino yes This picture looks exactly like mine from inside. The holes on my engine cover are connected to a pipe and there is an opening on top of the thermostat to accept the air.

 

I still don't know how you managed to remove the thermostat? Because it does not look like it will fit through by pushing springs by hand. There is not enough space.

 

In the middle of 2 springs there is a plastic piece which seems like can be opened? I am not quite sure how to remove it either. That is why I ordered a used cheap box to experiment on Any hints would be welcome.

Yeah, I vaguely remember disconnecting the flap itself from the plastic rod that moves it, then using a lot of force to get the thermostat out. Strong pliers to hold parts will maybe save injuries.

@Wino there is no way to insert it back unless the pin is retracted into the thermostat. Because there is not enough space even if you compress the spring all the way. How did you insert it back?

I can't remember, sorry.

Maybe the BCB engine has a slightly different design with dimensions that make it harder. But if you consider that somebody must have assembled it into there, it should be able to be removed.