I have 2 questions (OK 3, but who's countintg)

1) on a 76 (and probably other years), there a vacuum fitting on the back of the air cleaner housing. One comes from the carb and the other goes to the front of the air cleaner. It operates a little door that closes off outside air and sucks in from the heated air coming off the exhaust manifold. It seems to be temp operated. Now the question, does it matter which of the vacuum studs in that little temp thing goes to the front and which one goes to the carb?

2) how hot does it need to be before it closes off vacuum and allows the little door to close?

3) if it's bad, how does one remove the blasted thing and is it a part that's still made.

4) My bonus question, does it take a little while for the gasket around the thermostat housing to seat? I'm getting a little leakage around it after replacing the thermostat. (I did check the bolts and they're tight, and I did use blue permatex between the gasket and the intake manifold. should i have also used some between the gasket and the therm housing?

Wow, I got 5 questions for the price of 3. I love this forum.

Jeff S.

 

ok, I'll try my hand at your 2 questions (5 questions)

1. )If I am thinking of the correct part it is a small thermal device located on the underside of the air cleaner housing - it takes a prted vaccum source and routes it through this switch - and is then routed to the hot air door in teh snorkle of the air cleaner assembly. (A.) No, I do not believe it matters which port is connected to which hose - although I do believe it is important to be connected to the correct port on the carb.

2.)I believe it tries to maintain a 100 degree temp - I could be very wrong about this though - so awit further confirmation

3.)The part is still available at most parts stores - although getting hte name correct might be difficult - I would take the part in with you when purchasing the new one - I believe it is retained via a spring clip on the underside of the air cleaner assembly

4.)It takes no time for the gasket to seat - if it is leaking now - it is likely to continue to leak. Use a little bit of P Blue on both sides, you do not have to glop it on too thickly, also allow the sealant to skin - 3-4 mins. before installing and you will usually get a leak free seal.

Hope it all helps...

 

Thanks.
I'm sure it's connected to the right port on the carb. I took the air cleaner off to get to the therm housing to replace the thermosat. I just didn't write down which of the ports was hooked to which line. I pulled them both off (my mistake). I noticed the door was closing off when the car was running, but after it warmed up, it stayed closed. Either the part is bad or it never got hot enough. It was kind of cool out today so it may have never got hot enough to get over 100 under the hood. I'll take it for a longer drive to see if the thing works before replacing what could be a good part.

As for the therm housing gasket, guess I'll be replacing it tomorrow. What fun. I'll put some blue stuff on both sides.

Thanks again.
Jeff

 

I have been told by many mechanics that the only reason why people use STUFF on a t-stat gasket is to keep it in place while installing, sometimes doing more harm then good. Make sure the surface is clean, no left over gasket, get another gasket, and try your luck again.

 

I hate that "blue goo". I actually hate all of the silicone "glop" that you see pouring out around the edges of everyone's engines. You should not have a leak with the new gasket. Buy another gasket. Take it off again. When you do, make sure that both mating surfaces are perfectly clean...no old gasket pieces, no old "glop". Also check for damage such as pits, cracks etc, and also check for warpage. Any of these could be your problem. I use old "Indian Head Gasket Shellac" on my gaskets just to hold them in place, not to compensate for any defects. Hope this helps. Chuck

 

That little door motor has 2 fittings on it,vacuum & vent. If you hooked up the thermo signal to the vent port on the motor it won't open. If you want to override it hook vacuum up to the motor directly. I think all the cold engine items are best used when you can use them.

 

Chuck, I agree about too much glop hanging all over an engine, making it loos sloppy as hell, but in fact not using any at all will make the thing home to the leak....wether it's t-stat housing or valve covers, or bolts into an oil/water gallery...not blind in other words....not using any or an adequate amount of Silicone sealant in those areas, including of course the front and rear of the intake manifolds will make a worse looking mess, unless it's a museum piece....

GENE

 

Absolutely agreed - RTV pouring out of joints is very unattractive and unecessary - I use rtv (very sparingly) for several reasons

1) it helps to hold the gasket in alignment - especially on difficult pieces
2) it will HELP account for - warped, pitted and otherwise less than perfect mating surfaces.

If used only as needed and not as a replacement for quality componants it is a very worthwhile tool

 

I agree with the blue goo oozing out all over the place. I just put a very thin film on to hold gasket in place and fill in any pits or other minor defects.

I'm going to pull the therm housing and check it for flat. I picked up another gasket to day and will work on it tonight.

I will have to wait until it quits raining to check the temp sensor in the air cleaner housing.

I'll post what I find out.

Thanks,
Jeff

Jeff

 

OK, here's what I've found out. The therm housing was a little warped. The two ends where the bolts go through were bend down just a little. When I sat it on a flat piece of glass, I could see just a little light through the middle. I put sandpaper on my flat glass and sanded the housing flat again (I've filed and sanded flat many gun parts and triggers for muzzleloaders - bulding ml guns is a hobby of mine so I know how to keep the parts flat). Then took inletting black and placed on the bottom side of the therm housing and put it on a flat surface. It was a perfect mating surface. Then did the same for the mating surface to the intake. It was pretty good once I flattened the housing.

Then got a thicker gasket than the one that I got with the thermostat.

Without using any blue goo, I was able to reassemble the parts. I didn't drive it but did let it run in the driveway until the thermostat opened up. I let it run for about 5 more minutes and shut her off. No leak so far.

So my problem was, I believe twofold. 1) the gasket was a piece of junk and needed a thicker gasket. 2) the housing was slightly warped and needed some gentle correction.

I still don't know about the vacuum cutoff thing in the air cleaner housing. Have to wait until weekend to find out about that.

Jeff (call me Bubba) S.