a/c drain from a/c box - The 1947 - Present Chevrolet & GMC Truck Message Board Network

homemade87 · 06-19-2015, 02:45 PM

I have been driving my 82 some and have noticed when I run the air the condensed water from the a/c box is dumping on the inner fender and running out the bottom all over the place on the body . I know this will eventually create rust. When I did my resto I never thought about the drain . I can feel a hole in the bottom where I think it is coming from the a/c box . I looked on lmc and did not see anything . Does any one have some info on where the drain is supposed to drain and if there is a rubber grommet or something I am suppose to have .

homemade87 · 06-20-2015, 07:45 AM

I would of thought I would have gotten a response . As many of us that has had there truck apart including me I would have thought at least one of us would have paid attention to the a/c evaporator drain and how it drains .Could be that the way it is, is the way it is . I should have pay closer attention .It just did not cross my mine . I may have to remove the inner fender to see what really is going on . Just cant see under there . Maybe some one has a picture of the under side of the a/c housing and can post it .

Maybe Keith can shed some light on it . He has seen most everything on these trucks .

**hatzie** · 06-21-2015, 12:39 PM

There's no drain listed in the parts books.

Kaysen · 06-21-2015, 05:13 PM

The drain is just a 3/8" hole in the bottom of the evaporator box. I just had the box on my 86 apart to replace the evaporator and noticed the drain hole

homemade87 · 06-22-2015, 06:56 AM

Thanks for everyones reply . I could feel the hole under there . Was not sure if that was where it was coming from . The hole is directly above the inner fender .I can not see under there , it is to tight .If this is the case I may remove my inner fender and try to attach a hose and try to redirect it to the ground to get the water off the inner fender and the body seams down below . With it running down this way it is nothing but a rust problem in the future . I plan on keeping my truck after the resto and want to try to avoid problems that I do have some control over .

Keith Seymore · 06-22-2015, 07:33 AM

Thanks Hatzie and Kaysen.

I was going to check the parts book first thing this morning.

K

**hatzie** · 06-22-2015, 07:07 PM

AC condensate is distilled water with zero or darn close to zero contaminants.
It's pure distilled water. It should have a neutral PH of 7. I wouldn't worry about it.

homemade87 · 06-23-2015, 07:29 AM

Quote:

Originally Posted by hatzie

AC condensate is distilled water with zero or darn close to zero contaminants.
It's pure distilled water. It should have a neutral PH of 7. I wouldn't worry about it.

Good point , I agree it's not as corrosive as rain water . Rain water picks up a lot of things in the atmosphere . Depends on where you live .

06-19-2015, 02:45 PM	#1
homemade87 Registered User Join Date: Apr 2010 Location: Guntersville Alabama Posts: 1,073	a/c drain from a/c box I have been driving my 82 some and have noticed when I run the air the condensed water from the a/c box is dumping on the inner fender and running out the bottom all over the place on the body . I know this will eventually create rust. When I did my resto I never thought about the drain . I can feel a hole in the bottom where I think it is coming from the a/c box . I looked on lmc and did not see anything . Does any one have some info on where the drain is supposed to drain and if there is a rubber grommet or something I am suppose to have .

06-20-2015, 07:45 AM	#2
homemade87 Registered User Join Date: Apr 2010 Location: Guntersville Alabama Posts: 1,073	Re: a/c drain from a/c box I would of thought I would have gotten a response . As many of us that has had there truck apart including me I would have thought at least one of us would have paid attention to the a/c evaporator drain and how it drains .Could be that the way it is, is the way it is . I should have pay closer attention .It just did not cross my mine . I may have to remove the inner fender to see what really is going on . Just cant see under there . Maybe some one has a picture of the under side of the a/c housing and can post it . Maybe Keith can shed some light on it . He has seen most everything on these trucks .

06-21-2015, 12:39 PM	#3
hatzie Moderator Join Date: Oct 2008 Location: Wentworth, NH Posts: 4,977	Re: a/c drain from a/c box There's no drain listed in the parts books. __________________ 1959 M35A2 LDT465-1D SOLD 1967 Dodge W200 B383, NP420/NP201 SOLD 1969 Dodge Polara 500 B383, A833 SOLD 1972 Ford F250 FE390, NP435/NP205 SOLD 1976 Chevy K20, 6.5L, NV4500/NP208 SOLD 1986 M1008 CUCV SOLD 2000 GMC C2500, TD6.5L, NV4500 2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263 2009 Impala SS LS4 V8 RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials... 1973-1991 GM Light Truck Service, Unit/Overhaul, Wiring Manuals, Parts Books and Some 1968-1999 GM Service Training textbooks in PDF 1988-1998 GMT400 CK service manual project 1988-1993 GMT400 CK parts books. 1967-1972 GM Light, Medium, & Heavy Truck Service Manuals in PDF Please include at least the year and model in your threads. It'll be easier to answer your questions. And please let us know if and how your repairs were successful.

06-21-2015, 05:13 PM	#4
Kaysen Registered User Join Date: Dec 2013 Location: Marietta, OK Posts: 277	Re: a/c drain from a/c box The drain is just a 3/8" hole in the bottom of the evaporator box. I just had the box on my 86 apart to replace the evaporator and noticed the drain hole

06-22-2015, 06:56 AM	#5
homemade87 Registered User Join Date: Apr 2010 Location: Guntersville Alabama Posts: 1,073	Re: a/c drain from a/c box Thanks for everyones reply . I could feel the hole under there . Was not sure if that was where it was coming from . The hole is directly above the inner fender .I can not see under there , it is to tight .If this is the case I may remove my inner fender and try to attach a hose and try to redirect it to the ground to get the water off the inner fender and the body seams down below . With it running down this way it is nothing but a rust problem in the future . I plan on keeping my truck after the resto and want to try to avoid problems that I do have some control over .

06-22-2015, 07:33 AM	#6
Keith Seymore Registered User Join Date: May 2009 Location: Motor City Posts: 9,230	Re: a/c drain from a/c box Thanks Hatzie and Kaysen. I was going to check the parts book first thing this morning. K __________________ Chevrolet Flint Assembly 1979-1986 GM Full Size Truck Engineering 1986 - 2019 Intro from an Old Assembly Guy: http://67-72chevytrucks.com/vboard/s...d.php?t=342926 My Pontiac story: http://forums.maxperformanceinc.com/...d.php?t=560524 Chevelle intro: http://www.superchevy.com/features/s...hevy-chevelle/

06-22-2015, 07:07 PM	#7
hatzie Moderator Join Date: Oct 2008 Location: Wentworth, NH Posts: 4,977	Re: a/c drain from a/c box AC condensate is distilled water with zero or darn close to zero contaminants. It's pure distilled water. It should have a neutral PH of 7. I wouldn't worry about it. __________________ 1959 M35A2 LDT465-1D SOLD 1967 Dodge W200 B383, NP420/NP201 SOLD 1969 Dodge Polara 500 B383, A833 SOLD 1972 Ford F250 FE390, NP435/NP205 SOLD 1976 Chevy K20, 6.5L, NV4500/NP208 SOLD 1986 M1008 CUCV SOLD 2000 GMC C2500, TD6.5L, NV4500 2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263 2009 Impala SS LS4 V8 RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials... 1973-1991 GM Light Truck Service, Unit/Overhaul, Wiring Manuals, Parts Books and Some 1968-1999 GM Service Training textbooks in PDF 1988-1998 GMT400 CK service manual project 1988-1993 GMT400 CK parts books. 1967-1972 GM Light, Medium, & Heavy Truck Service Manuals in PDF Please include at least the year and model in your threads. It'll be easier to answer your questions. And please let us know if and how your repairs were successful.

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