quick ? about my air-box - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Seke69 · 05-20-2003, 05:29 AM

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 · 05-20-2003, 07:52 AM

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 · 05-20-2003, 10:58 AM

are you looking at the washer pump?

cdowns · 05-20-2003, 11:23 AM

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 · 05-21-2003, 02:54 AM

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 · 05-21-2003, 06:42 AM

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 · 05-21-2003, 07:34 AM

(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 · 05-21-2003, 12:10 PM

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** · 05-21-2003, 01:40 PM

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** · 05-21-2003, 01:41 PM

more

**CPNE** · 05-21-2003, 01:42 PM

last one

JimKshortstep4x4 · 05-21-2003, 01:47 PM

Hey Jeff!

Good information. Pictures sure explain better than words.

Jim

**CPNE** · 05-21-2003, 01:52 PM

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 · 05-21-2003, 02:19 PM

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 · 05-22-2003, 01:36 AM

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...

05-20-2003, 05:29 AM	#1
Seke69 Space Cadet Join Date: Mar 2003 Location: Twin Cities Posts: 132	quick ? about my air-box 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...

05-20-2003, 10:58 AM	#3
smokekiki Mike Join Date: Jan 2003 Location: west chester pa Posts: 2,474	are you looking at the washer pump? __________________ 70'c/10, 71 suburban4x4 402bb, 72suburban 4/6 drop, 72k/5 4x4 blazer 4" lift 35 tires

05-20-2003, 11:23 AM	#4
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	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 __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

05-21-2003, 07:34 AM	#7
Seke69 Space Cadet Join Date: Mar 2003 Location: Twin Cities Posts: 132	(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 Last edited by Seke69; 05-21-2003 at 07:41 AM.

05-21-2003, 01:40 PM	#9
CPNE Resident Curmudgeon Join Date: Dec 1999 Location: NH Posts: 6,664	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 Attached Images __________________ Currently on or near the homestead: 67 Chevy SWB 2WD stepside 350/3 on tree (Pat's) 67 GMC SWB 2WD Fleet 402/auto (Brian's under construction) 67 Chevy 3/4 ton 2WD 402/auto (Business Hauler) 67 Chevy 1 ton dually 2WD 396/4 speed (Former business hauler, Needs TLC) 68 Chevy 1/2 ton Suburban 2WD 250 six/3 on tree (Brian's Needs TLC) 70 Chevy 3/4 ton 4WD 350/4 speed (Pat's - Disguised as a 68 GMC) 71 Chevy SWB stepside (Crushed by tree - parts donor) 72 Chevy 3/4 ton 4WD (Parts donor) 72 Chevy 3/4 ton 4WD Suburban (Parts Donor) 72 GMC 3/4 ton 4WD 292 six/4 speed (Mine - Disguised as a 67 GMC) 81 GMC 4WD Dually Dump Body 350/4 speed (Business Hauler) 82 Camaro Z/28 355/Super T-10 (Pat's toy) 93 Caprice 9C1 (Brian's Cop Car) 02 Toyota Camry (Reliable but a souless steel and plastic hulk) 2011 2SS RS Camaro M6 Factory Hurst Shifter Maybe I need to sell some of this crap Yet another Bozo with a sawz-all Last edited by CPNE; 05-21-2003 at 01:44 PM.

05-20-2003, 07:52 AM	#2
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	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

05-21-2003, 02:54 AM	#5
Seke69 Space Cadet Join Date: Mar 2003 Location: Twin Cities Posts: 132	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...

05-21-2003, 06:42 AM	#6
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	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

05-21-2003, 12:10 PM	#8
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	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

05-21-2003, 01:41 PM	#10
CPNE Resident Curmudgeon Join Date: Dec 1999 Location: NH Posts: 6,664	more Attached Images __________________ Currently on or near the homestead: 67 Chevy SWB 2WD stepside 350/3 on tree (Pat's) 67 GMC SWB 2WD Fleet 402/auto (Brian's under construction) 67 Chevy 3/4 ton 2WD 402/auto (Business Hauler) 67 Chevy 1 ton dually 2WD 396/4 speed (Former business hauler, Needs TLC) 68 Chevy 1/2 ton Suburban 2WD 250 six/3 on tree (Brian's Needs TLC) 70 Chevy 3/4 ton 4WD 350/4 speed (Pat's - Disguised as a 68 GMC) 71 Chevy SWB stepside (Crushed by tree - parts donor) 72 Chevy 3/4 ton 4WD (Parts donor) 72 Chevy 3/4 ton 4WD Suburban (Parts Donor) 72 GMC 3/4 ton 4WD 292 six/4 speed (Mine - Disguised as a 67 GMC) 81 GMC 4WD Dually Dump Body 350/4 speed (Business Hauler) 82 Camaro Z/28 355/Super T-10 (Pat's toy) 93 Caprice 9C1 (Brian's Cop Car) 02 Toyota Camry (Reliable but a souless steel and plastic hulk) 2011 2SS RS Camaro M6 Factory Hurst Shifter Maybe I need to sell some of this crap Yet another Bozo with a sawz-all

05-21-2003, 01:42 PM	#11
CPNE Resident Curmudgeon Join Date: Dec 1999 Location: NH Posts: 6,664	last one Attached Images __________________ Currently on or near the homestead: 67 Chevy SWB 2WD stepside 350/3 on tree (Pat's) 67 GMC SWB 2WD Fleet 402/auto (Brian's under construction) 67 Chevy 3/4 ton 2WD 402/auto (Business Hauler) 67 Chevy 1 ton dually 2WD 396/4 speed (Former business hauler, Needs TLC) 68 Chevy 1/2 ton Suburban 2WD 250 six/3 on tree (Brian's Needs TLC) 70 Chevy 3/4 ton 4WD 350/4 speed (Pat's - Disguised as a 68 GMC) 71 Chevy SWB stepside (Crushed by tree - parts donor) 72 Chevy 3/4 ton 4WD (Parts donor) 72 Chevy 3/4 ton 4WD Suburban (Parts Donor) 72 GMC 3/4 ton 4WD 292 six/4 speed (Mine - Disguised as a 67 GMC) 81 GMC 4WD Dually Dump Body 350/4 speed (Business Hauler) 82 Camaro Z/28 355/Super T-10 (Pat's toy) 93 Caprice 9C1 (Brian's Cop Car) 02 Toyota Camry (Reliable but a souless steel and plastic hulk) 2011 2SS RS Camaro M6 Factory Hurst Shifter Maybe I need to sell some of this crap Yet another Bozo with a sawz-all

05-21-2003, 01:47 PM	#12
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	Hey Jeff! Good information. Pictures sure explain better than words. Jim

05-21-2003, 01:52 PM	#13
CPNE Resident Curmudgeon Join Date: Dec 1999 Location: NH Posts: 6,664	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!) __________________ Currently on or near the homestead: 67 Chevy SWB 2WD stepside 350/3 on tree (Pat's) 67 GMC SWB 2WD Fleet 402/auto (Brian's under construction) 67 Chevy 3/4 ton 2WD 402/auto (Business Hauler) 67 Chevy 1 ton dually 2WD 396/4 speed (Former business hauler, Needs TLC) 68 Chevy 1/2 ton Suburban 2WD 250 six/3 on tree (Brian's Needs TLC) 70 Chevy 3/4 ton 4WD 350/4 speed (Pat's - Disguised as a 68 GMC) 71 Chevy SWB stepside (Crushed by tree - parts donor) 72 Chevy 3/4 ton 4WD (Parts donor) 72 Chevy 3/4 ton 4WD Suburban (Parts Donor) 72 GMC 3/4 ton 4WD 292 six/4 speed (Mine - Disguised as a 67 GMC) 81 GMC 4WD Dually Dump Body 350/4 speed (Business Hauler) 82 Camaro Z/28 355/Super T-10 (Pat's toy) 93 Caprice 9C1 (Brian's Cop Car) 02 Toyota Camry (Reliable but a souless steel and plastic hulk) 2011 2SS RS Camaro M6 Factory Hurst Shifter Maybe I need to sell some of this crap Yet another Bozo with a sawz-all

05-21-2003, 02:19 PM	#14
wnc mountain More hobbies than money! Join Date: Jan 2002 Location: Raleigh, nc, usa Posts: 655	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. __________________ '70 cst10/swb 350, 3 on the tree, factory buckets. '70 GMC lwb 350/350 ps,pb '72 c-10 lwb 350/350 a/c, ps, pb '72 Blazer project

05-22-2003, 01:36 AM	#15
Seke69 Space Cadet Join Date: Mar 2003 Location: Twin Cities Posts: 132	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... Last edited by Seke69; 05-22-2003 at 01:45 AM.



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