Thermac switch?

[davepl]

I might have the wrong name, as I'm having no luck finding it.

I need the little thermal vacuum switch that goes inside the air cleaner housing and controls the opening of the heat stove flapper valve.

Anyone know what its called and where I can find them? Should be a common service part, you'd think.

Thanks!
Dave

PS: In case anyone ever wonders, I had my Air Cleaner housing powder coated. I was worried that the heat would ruin the return spring and didn't want to take it apart, so risked it. All tests are fine, I've connected vacuum and seen it do its thing and watched it return.

For that matter I had my front coil springs done too, and they're probably more important than the emissions flapper door air cleaner return spring!

[davepl]

TTT

Still broken, still need one. Gotta be a million of them in wrecking yards, I just don't have one of those for 50 miles....

[davepl]

BTW, I can't find them at auto parts stores or LMC or Brothers or CI or anywhere. eBay has a few listings, but none that claim to be compatible with my truck. The closest looking one I can find is the ATS22, but they're about $50 on eBay

http://www.ebay.com/itm/Standard-Mot...b1d3f7&vxp=mtr

[Oldtruckfanatic]

Look like this ?

[davepl]

Yes, please remove it carefully before sending it to me :-) I would probably need the retaining clip as well, I think.

In all seriousness, is it a part you'll part with?

Thanks
Dave

[Oldtruckfanatic]

I have the entire assembly Its off of a 71 350. Id rather send you the entire air cleaner housing I really dont want to break the switch lol

[davepl]

Before asking you to ship a huge unit, I did a little more anthropology. In my parts counter book it shows the GM part number as 3979573. Googling that with "interchange" took me to some photos, so picking the ones that looked like it led me to this supposed interchange list:

GM 3979573
#19111948
Standard ATS6

Five bucks on Rock Auto. They don't show it fitting my truck, but they have it under "1978 C10 250cid L6".

http://www.rockauto.com/catalog/more...157&cc=1296413

[Oldtruckfanatic]

No problem I bet that willl work. Im just afraid to break this one trying to get it out for you. I have no problem parting with it I dont do restorations on my own stuff Just hotrods. This air cleaner has been sitting on the stock engine from that truck in the corner of my shop for a year.

[davepl]

Do you know if that's off a 396 or a 350? I'm pretty sure I'm missing the retaining clip. I had mine powder coated so I stripped it apart, which is how I got into this mess.

[Oldtruckfanatic]

Its a factory 350 from a 71 camper special. I have a 402 but the air cleaner was long gone when I got it.

[Oldtruckfanatic]

Let me see if I can remove it. Its not like im going to use it.

[davepl]

I was going to encourage you to try, but didn't want you to break it. Since I can probably find the switch, it's not the end of the world even if it does break. But the clip is... that's the apocalypse right there if I can't get that. Well, I could be exaggerating :-)

Let me know if you can get it out, how much you'd like, and how to send it to you!

Thanks much!
Dave

[Andy4639]

Here is what the manual calls it. How it works.

[davepl]

Yup, I know how they work. I never really know how to test them. I mean you can heat them with a hair dryer, but how do you know if opened/closed at 100F?

You guys in the south could just walk outdoors with it, but not here!

[Oldtruckfanatic]

Well here it is. Who knows if it works but its not broken nor is the retainer.

[Andy4639]

Here is what the manual says to do to test it.
High tech stuff right here man! Lol...
It would be easy to check it today here it's like 72* and raining.