Red Assembly Mark on A/C boxes - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**IronCanine** · 01-05-2020, 02:43 AM

On some A/C boxes there was a red paint mark from the factory. At least I interpret it as paint. I have seen many more boxes without a mark than ones with a mark. I believe it to be a Harrison mark, not a final assembly plant mark. But I am speculating. It appears on other GM makes of the era and on vehicles from different assembly plants. The location of the mark can vary. Most all I have seen were at the top front, but I have seen it at the bottom and side. Here are a few pics I've collected from the board at large and from members directly. First two pics are St. Louis trucks, fifth pic is Flint. The fourth pic is from our build and an attempt to recreate this mark. I have had conversations with members about the meaning of this mark and found no consensus. I didn't have much luck noodling around the Corvette, Chevelle or Camaro forums either. F.A.A.Benny would be a good voice to offer an informed perspective on this.

I'm not aware of other threads discussing this and thought a discussion and pics might be of use to someone down the road (and I have an affinity for factory processes/markings). If nothing else maybe we can get another thread with factory underhood A/C pics.

**BigBird05** · 01-05-2020, 09:24 AM

That mark is usually a quality control mark.

**IronCanine** · 01-05-2020, 09:34 AM

Quote:

Originally Posted by BigBird05

That mark is usually a quality control mark.

That was my assumption due to the limited frequency.

**DeadheadNM** · 01-05-2020, 10:39 AM

Good thread. Here are some Flint assembled 72 K5s w red dot.

**maverickmk** · 01-05-2020, 10:56 AM

I am no AC expert, but I wonder if it is either the high side or the heat/exit side - ?

**davischevy** · 03-23-2020, 09:23 PM

That is new one for me. I'll probably spend all morning tomorrow out back doing "Research".

**IronCanine** · 03-23-2020, 09:47 PM

That'd be great Larry. Pics if you can.

**davischevy** · 03-23-2020, 10:21 PM

Quote:

Originally Posted by IronCanine

That'd be great Larry. Pics if you can.

I have a half dozen original paint Chevelles too. I will look them over too.

72swbcamo · 03-24-2020, 01:49 PM

I have two A/C units and half of a housing where the mark would be. One has the red mark, not a nice round circle, more like the red mark in the last picture in the thread. I have no idea what it means but it sure is a great conversation starter. I'm sure someone on this site will come up with the definitive answer.

**davischevy** · 03-24-2020, 08:40 PM

The first two pictures are a St Louis manufactured truck.

The third is Fremont built.

**IronCanine** · 03-24-2020, 09:02 PM

Thanks for posting Larry. That's a lot of red marks! The last one really looks like a brush stroke.

**davischevy** · 03-24-2020, 09:08 PM

The first one does too.

**davischevy** · 03-25-2020, 11:32 PM

I found another one today. This is a 56,000 mile C10 we bought out of the estate of the original owner. Fremont built.

**maverickmk** · 03-26-2020, 09:46 AM

If I understand correctly, the high side of an AC system has the larger hose and is the warm hose. I'm thinking that is why there is red markings near the larger line - ?

**davischevy** · 03-26-2020, 11:21 PM

I found this one on a 72 Monte Carlo on the tube itself.

**davischevy** · 03-26-2020, 11:24 PM

This one is on a low mileage 69 Impala.

toolboxchev · 03-27-2020, 09:02 AM

Sone form of QC check mark. Or verification the system is sealed, charged, assembled properly.

**IronCanine** · 03-27-2020, 10:11 AM

Quote:

Originally Posted by toolboxchev

Sone form of QC check mark. Or verification the system is sealed, charged, assembled properly.

Larry (davischevy) has quite a lot of these in his stash. It seems to me there are a lot more floating around without the mark than with. And we have shown the same mark from different assembly plants. Unlike other assembly marks that we have shown to vary from plant to plant (see any one of our factory markings threads-there are a few on here). Because this mark seems to be consistent from plant to plant on different makes and models...I think it's a Harrison mark. I would think that the box assembly would come from Harrison as a subassembly to be mounted on the truck. Keith Seymore might weigh in as I don't think this assembly process would have changed much on the square bodies (of which he has direct knowledge). But if it is a Harrison mark, then it's got to be QC mark of some sort and not an indication of charge. Now I know that Larry has found red marks on hoses...that could be an indication of charge or factory assembly check. But his examples of this are other GM models-not trucks.

Keith Seymore · 03-27-2020, 10:51 AM

I agree completely, IronCanine.

K

**davischevy** · 03-27-2020, 12:41 PM

Here is a 62 Impala. The marks are on the hoses at the rear of the compressor and the core support.

**IronCanine** · 03-27-2020, 07:16 PM

Quote:

Originally Posted by Keith Seymore

I agree completely, IronCanine.

K

This is one of the great moments of my life. I think I may make a T shirt out of this. Thanks Keith.

Quote:

Originally Posted by davischevy

Here is a 62 Impala. The marks are on the hoses at the rear of the compressor and the core support.

Cool pics Larry. Thanks for posting.

**davischevy** · 03-27-2020, 09:31 PM

My 71 Chevelle SS 454. A friend of mine bought this car new.

Edit; This car was built in Arlington, TX

**FirstOwner69** · 03-30-2020, 08:32 PM

This is on a '72 currently on Phoenix Craigslist. Looks like a Janesville truck.
https://phoenix.craigslist.org/evl/c...092213597.html

**IronCanine** · 03-30-2020, 09:42 PM

Great addition Jim. Best one I've seen.

**402Bowtie** · 03-20-2021, 11:52 PM

Barely in the pic, but there. This is a Baltimore truck. https://denver.craigslist.org/cto/d/...294467795.html

01-05-2020, 02:43 AM	#1
IronCanine I'm trying.... Join Date: Oct 2013 Location: Athens, GA Posts: 2,538	Red Assembly Mark on A/C boxes On some A/C boxes there was a red paint mark from the factory. At least I interpret it as paint. I have seen many more boxes without a mark than ones with a mark. I believe it to be a Harrison mark, not a final assembly plant mark. But I am speculating. It appears on other GM makes of the era and on vehicles from different assembly plants. The location of the mark can vary. Most all I have seen were at the top front, but I have seen it at the bottom and side. Here are a few pics I've collected from the board at large and from members directly. First two pics are St. Louis trucks, fifth pic is Flint. The fourth pic is from our build and an attempt to recreate this mark. I have had conversations with members about the meaning of this mark and found no consensus. I didn't have much luck noodling around the Corvette, Chevelle or Camaro forums either. F.A.A.Benny would be a good voice to offer an informed perspective on this. I'm not aware of other threads discussing this and thought a discussion and pics might be of use to someone down the road (and I have an affinity for factory processes/markings). If nothing else maybe we can get another thread with factory underhood A/C pics. Attached Images __________________ 1970 Blazer http://67-72chevytrucks.com/vboard/s...d.php?t=645076 1969 K10 SWB CST http://67-72chevytrucks.com/vboard/s...52#post8520352 1971 K20 Z84 https://67-72chevytrucks.com/vboard/...90#post9047290 1946 B.F. Avery Model A Tractor http://67-72chevytrucks.com/vboard/s...55#post8292555 "Sometimes I wonder if zander208 was even real..."

01-05-2020, 09:24 AM	#2
BigBird05 Senior Member Join Date: Aug 2019 Location: Cheraw Posts: 1,305	Re: Red Assembly Mark on A/C boxes That mark is usually a quality control mark.

01-05-2020, 10:39 AM	#4
DeadheadNM Carpe manana Join Date: Dec 2010 Location: Eau Claire, WI Posts: 12,297	Re: Red Assembly Mark on A/C boxes Good thread. Here are some Flint assembled 72 K5s w red dot. Attached Images __________________ 1972 K5 CST Highlander Blazer: http://67-72chevytrucks.com/vboard/s...d.php?t=708547 1972 K20 Cheyenne Super: http://67-72chevytrucks.com/vboard/s...d.php?t=528308 Members met: ORANGBLAZ, 2003 silverado, MikeCofield, BB72CHEVKT, Duncan&Son, Sameyrasmea72, THENEWMEXICAN, HotRod C/10, brianthelion02, Sport/Truck, ryanroo, michael bustamante, Dirt's72, Already Gone, WestButteTruck, 57taskforce, Moreyel, painterljp, AASmedic, SoCoC10, Lumaestas, carbuff382, Chevyland

01-05-2020, 10:56 AM	#5
maverickmk Senior Member Join Date: Nov 2019 Location: Cocoa FL Posts: 596	Re: Red Assembly Mark on A/C boxes I am no AC expert, but I wonder if it is either the high side or the heat/exit side - ? __________________ Die with memories, not dreams. Not to brag, but I don't need alcohol to make really bad decisions. 1969 GMC Short Step Side

03-23-2020, 09:23 PM	#6
davischevy Senior Member Join Date: Sep 2008 Location: Harrison, Arkansas Posts: 9,788	Re: Red Assembly Mark on A/C boxes That is new one for me. I'll probably spend all morning tomorrow out back doing "Research". __________________ other Larry Build thread, Arkansas K10 https://67-72chevytrucks.com/vboard/...=755797&page=5 The ability to speak several languages is an asset, but the ability to keep your mouth shut in any language is priceless.

03-23-2020, 09:47 PM	#7
IronCanine I'm trying.... Join Date: Oct 2013 Location: Athens, GA Posts: 2,538	Re: Red Assembly Mark on A/C boxes That'd be great Larry. Pics if you can. __________________ 1970 Blazer http://67-72chevytrucks.com/vboard/s...d.php?t=645076 1969 K10 SWB CST http://67-72chevytrucks.com/vboard/s...52#post8520352 1971 K20 Z84 https://67-72chevytrucks.com/vboard/...90#post9047290 1946 B.F. Avery Model A Tractor http://67-72chevytrucks.com/vboard/s...55#post8292555 "Sometimes I wonder if zander208 was even real..."

03-24-2020, 01:49 PM	#9
72swbcamo Active Member Join Date: Dec 2003 Location: Waterbury, CT Posts: 591	Re: Red Assembly Mark on A/C boxes I have two A/C units and half of a housing where the mark would be. One has the red mark, not a nice round circle, more like the red mark in the last picture in the thread. I have no idea what it means but it sure is a great conversation starter. I'm sure someone on this site will come up with the definitive answer.

03-24-2020, 08:40 PM	#10
davischevy Senior Member Join Date: Sep 2008 Location: Harrison, Arkansas Posts: 9,788	Re: Red Assembly Mark on A/C boxes The first two pictures are a St Louis manufactured truck. The third is Fremont built. Attached Images __________________ other Larry Build thread, Arkansas K10 https://67-72chevytrucks.com/vboard/...=755797&page=5 The ability to speak several languages is an asset, but the ability to keep your mouth shut in any language is priceless.

03-24-2020, 09:02 PM	#11
IronCanine I'm trying.... Join Date: Oct 2013 Location: Athens, GA Posts: 2,538	Re: Red Assembly Mark on A/C boxes Thanks for posting Larry. That's a lot of red marks! The last one really looks like a brush stroke. __________________ 1970 Blazer http://67-72chevytrucks.com/vboard/s...d.php?t=645076 1969 K10 SWB CST http://67-72chevytrucks.com/vboard/s...52#post8520352 1971 K20 Z84 https://67-72chevytrucks.com/vboard/...90#post9047290 1946 B.F. Avery Model A Tractor http://67-72chevytrucks.com/vboard/s...55#post8292555 "Sometimes I wonder if zander208 was even real..."

03-24-2020, 09:08 PM	#12
davischevy Senior Member Join Date: Sep 2008 Location: Harrison, Arkansas Posts: 9,788	Re: Red Assembly Mark on A/C boxes The first one does too. Attached Images __________________ other Larry Build thread, Arkansas K10 https://67-72chevytrucks.com/vboard/...=755797&page=5 The ability to speak several languages is an asset, but the ability to keep your mouth shut in any language is priceless.

03-25-2020, 11:32 PM	#13
davischevy Senior Member Join Date: Sep 2008 Location: Harrison, Arkansas Posts: 9,788	Re: Red Assembly Mark on A/C boxes I found another one today. This is a 56,000 mile C10 we bought out of the estate of the original owner. Fremont built. Attached Images __________________ other Larry Build thread, Arkansas K10 https://67-72chevytrucks.com/vboard/...=755797&page=5 The ability to speak several languages is an asset, but the ability to keep your mouth shut in any language is priceless.

03-26-2020, 09:46 AM	#14
maverickmk Senior Member Join Date: Nov 2019 Location: Cocoa FL Posts: 596	Re: Red Assembly Mark on A/C boxes If I understand correctly, the high side of an AC system has the larger hose and is the warm hose. I'm thinking that is why there is red markings near the larger line - ? __________________ Die with memories, not dreams. Not to brag, but I don't need alcohol to make really bad decisions. 1969 GMC Short Step Side

03-26-2020, 11:21 PM	#15
davischevy Senior Member Join Date: Sep 2008 Location: Harrison, Arkansas Posts: 9,788	Re: Red Assembly Mark on A/C boxes I found this one on a 72 Monte Carlo on the tube itself. Attached Images __________________ other Larry Build thread, Arkansas K10 https://67-72chevytrucks.com/vboard/...=755797&page=5 The ability to speak several languages is an asset, but the ability to keep your mouth shut in any language is priceless.

03-26-2020, 11:24 PM	#16
davischevy Senior Member Join Date: Sep 2008 Location: Harrison, Arkansas Posts: 9,788	Re: Red Assembly Mark on A/C boxes This one is on a low mileage 69 Impala. Attached Images __________________ other Larry Build thread, Arkansas K10 https://67-72chevytrucks.com/vboard/...=755797&page=5 The ability to speak several languages is an asset, but the ability to keep your mouth shut in any language is priceless.

03-27-2020, 09:02 AM	#17
toolboxchev Registered User Join Date: Jul 2015 Location: 2nd left past the stump on a dirt road. Posts: 2,629	Re: Red Assembly Mark on A/C boxes Sone form of QC check mark. Or verification the system is sealed, charged, assembled properly.



Register or Log In To remove these advertisements.

03-27-2020, 10:51 AM	#19
Keith Seymore Registered User Join Date: May 2009 Location: Motor City Posts: 9,152	Re: Red Assembly Mark on A/C boxes I agree completely, IronCanine. 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/

03-27-2020, 12:41 PM	#20
davischevy Senior Member Join Date: Sep 2008 Location: Harrison, Arkansas Posts: 9,788	Re: Red Assembly Mark on A/C boxes Here is a 62 Impala. The marks are on the hoses at the rear of the compressor and the core support. Attached Images __________________ other Larry Build thread, Arkansas K10 https://67-72chevytrucks.com/vboard/...=755797&page=5 The ability to speak several languages is an asset, but the ability to keep your mouth shut in any language is priceless.

03-27-2020, 09:31 PM	#22
davischevy Senior Member Join Date: Sep 2008 Location: Harrison, Arkansas Posts: 9,788	Re: Red Assembly Mark on A/C boxes My 71 Chevelle SS 454. A friend of mine bought this car new. Edit; This car was built in Arlington, TX Attached Images __________________ other Larry Build thread, Arkansas K10 https://67-72chevytrucks.com/vboard/...=755797&page=5 The ability to speak several languages is an asset, but the ability to keep your mouth shut in any language is priceless. Last edited by davischevy; 03-30-2020 at 09:37 PM.

03-30-2020, 08:32 PM	#23
FirstOwner69 Senior Member Join Date: May 2010 Location: Wisconsin & Arizona Posts: 4,839	Re: Red Assembly Mark on A/C boxes This is on a '72 currently on Phoenix Craigslist. Looks like a Janesville truck. https://phoenix.craigslist.org/evl/c...092213597.html Attached Images __________________ Jim

03-30-2020, 09:42 PM	#24
IronCanine I'm trying.... Join Date: Oct 2013 Location: Athens, GA Posts: 2,538	Re: Red Assembly Mark on A/C boxes Great addition Jim. Best one I've seen. __________________ 1970 Blazer http://67-72chevytrucks.com/vboard/s...d.php?t=645076 1969 K10 SWB CST http://67-72chevytrucks.com/vboard/s...52#post8520352 1971 K20 Z84 https://67-72chevytrucks.com/vboard/...90#post9047290 1946 B.F. Avery Model A Tractor http://67-72chevytrucks.com/vboard/s...55#post8292555 "Sometimes I wonder if zander208 was even real..." Last edited by IronCanine; 03-20-2021 at 11:56 PM.

03-20-2021, 11:52 PM	#25
402Bowtie Registered User Join Date: Sep 2003 Location: Denver, CO Posts: 3,722	Re: Red Assembly Mark on A/C boxes Barely in the pic, but there. This is a Baltimore truck. https://denver.craigslist.org/cto/d/...294467795.html Attached Images __________________ Link to Parts I am Selling Build Date Thread: GMC, 68-71 Chevy, 72 Chevy

Register or Log In To remove these advertisements.