quick ? about my air-box

[Seke69]

I have the stock 250 in my truck. on the bottom of my air box there is two rubber hoses for windshield wiper vaccuum, where they connect to in the body of the box there is a plastic part.

MINE'S MELTED. the inside of the box is covered in burnt plastic soot, as well as some of the carb, etc...

what is it? how is it supposed to look and is it a part I can just get from NAPA or somewhere similar?

also, what might have caused this?

as always, any help is appreciated pictures of an unmelted one would be great too...

[JimKshortstep4x4]

Just curious as to what year truck that you have that has vacuum wipers?

All of the 67-72's that I have seen have electric windshield wiper motors on them. I have not been able to tell what you are calling an "air box". Is this an ac truck?


Jim

[smokekiki]

are you looking at the washer pump?

[cdowns]

are you talking about your air filter housing on the carb, or the air phlenum for the heater or the winsheild washer pump?? might have a better chance of a responce if you'd state year and model and a better description of the THINGGY you think needs attention

[Seke69]

oops, sorry guys, it's a 69 (c-10), no AC, I haven't seen an electric wiper motor (they're kinda hard to miss) so I'm assuming that there isn't one. I know NOTHING about vaccuum powered stuff. I'm asking about the air filter housing. the piece is between the air filter and the carb. it looks like it was on fire. there's black soot (like burnt plastic) all over everything in the box (including the carb). part of the problem is that I have no idea what the thingy does, or what it's called, I'm thinking it's just a plastic clip for the tubing, but it looks more complicated than that, like it actually does something other than hold the tubing and I think there's something metallic in it (like a washer). I can't get the thing off either, 'cause it's melted, but only on the top, the tubing is fine (under the housing).

It's not a big deal part or anything, but I wanted to bust some rust and paint the box/lid, clean up, etc...

[JimKshortstep4x4]

From your description, the item you are looking at is the control valve for the thermactor door in the snout of the air cleaner. They tend to get black and sooty over time. I would try cleaning it before throwing it out.

Is your engine equipped wiht a heat shield over the exhaust manifold with a pipe going to the air cleaner snout?

If that has been eliminated, then the dirty valve is not doing anything for you. You can leave it in place and make sure that you don't have vacuum leaks from the hoses.

The windshield wiper motor is under the dash, just above the accelerator pedal.

Jim

[Seke69]

(it's crap not knowing what things are called)

on the snout of the air cleaner, top, there is small tobacco tin sized can, from the side of that can thing there is one rubber hose labeled "windshield wiper vaccuum line" (and a bunch of numbers). the hose runs under the air cleaner/box, to an area near the center of the box, this is where the melted thing is, it's mainly made of plastic, it's about the length and width of a stick of chewing gum I'm sure it used to be taller before it melted (I'd guess about 1/2inch tall). another piece of rubber tubing runs out from the bottom of the 'melted thingy' it is also labeled "windshield wiper vaccuum line" from there it runs to the left side of the firewall and disappears forever. I'll try to look around after I leave here (work). there's no heat shield over my exhaust manifold. thanks for your reply Jim.

-Steve

[JimKshortstep4x4]

If it were my truck, I would eliminate the vacuum hoses as they are not doing anything. The one hose should go to a vacuum source, so that will need to be plugged where it picks up vacuum.

The dirty vacuum valve can be left in place otherwise unfiltered air can come into the engine through the holes that the valve mounts in. It sounds like someone used washer hose on the air filter.

Jim

[CPNE]

Click here for explanation of what I think you are describing

It's called a Thermostatic Air Cleaner or TAC. GM calls it Thermac. Hope this helps

[CPNE]

more

[CPNE]

last one

[JimKshortstep4x4]

Hey Jeff!

Good information. Pictures sure explain better than words.

Jim

[CPNE]

Couldn't have done it without your reference to thermactor Jim. It's amazing what a web search can reveal. I'm not really that sharp, just able to filter info well. (XXL, here's another softball for ya!)

[wnc mountain]

sounds like his hemperature sensor inside the air cleaner is cooked. This is most likely from backfireing from being misstuned at some point. the part is most likely available at a parts store. print this tread out and take it to the store with you to help explain what you are looking for.
Good find CPNE. Info is power.

[Seke69]

yeah I feel kinda dumb 'cos the tubing I followed to the firewall didn't go there it went to the intake, it controls a little door inside the snout of the air cleaner which I think is for cold weather starting. the part, once I pried it out of the housing, looks like an old household thermistat or something and has a plastic clamshell kind of retainer, it needs to be replaced anyway...

thanks for all the help guys.

edit: the hose that connects along the bottom of the 'snorkel' to the hot air duct, does that need to be there? I don't have a shroud like that over my exhaust manifold for it to connect to...