Radiator Hoses
Race Director
Joined: Sep 2001
Posts: 10,560
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From: Wellington, FL
St. Jude Donor '11 thru '25
It may or may not be cooler depending on how well the flapper door seals seal. If it seals well, you will not notice any difference. If you are not concerned about heat in the winter, I would disconnect the heater hoses.
If your interior is getting hot on it's own as you say, check the seal on the rear of the hood. This is there to prevent hot engine compartment air from entering the cowling and your vent system. The difference this $8.00 seal can make is enormous and is an easily overlooked item. Without even looking at your car, if that seal hasn't been replaced in the last couple of years, I'd bet that it is at least one of your problems, if not the only one. You can check it by putting a little greese all around the surface and then shutting the hood. When opened, if the greese is not fully transferred to the sealing part of the cowling, that is your problem. Good luck!
As a side note, the '75's did not have a heater control valve.
Race Director
Joined: Sep 2001
Posts: 10,560
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From: Wellington, FL
St. Jude Donor '11 thru '25
Strange that's on a non a/c car as the purpose of the valve is to block water flow to the heater when the a/c is on. In any event, the '75 a/c car I had did not have one and I naturally thought someone had removed it. However, I checked the AIM manual and it shows they didn't come with one.
Last edited by Jud Chapin; Jan 21, 2007 at 02:42 PM.
Pro
Joined: Mar 2001
Posts: 633
Likes: 1
From: Hamilton, ON, Canada
Strange that's on a non a/c car as the purpose of the valve is to block water flow to the heater when the a/c is on. In any event, the '75 a/c car I had did not have one and I naturally thought someone had removed it. However, I checked the AIM manual and it shows they didn't come with one.
Race Director
Joined: Sep 2001
Posts: 10,560
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From: Wellington, FL
St. Jude Donor '11 thru '25
The only thing I'm going by is the AIM manuals. The '76 shows one and the '75 doesn't. If you have warm air coming from the vents, though, check the rear hood seal as I mentioned above. With the a/c off in my '76, the temperature from the vents was over 100 degrees after full engine warm up. I replaced the hood seal, and the temp dropped to 75 degrees, which was the outside temp. My a/c now blows at 40 degrees, the coldest it's ever been, and I bought the car new.
Pro
Joined: Mar 2001
Posts: 633
Likes: 1
From: Hamilton, ON, Canada
I checked my Assembly Manual- P.129- shows a heater control valve for all '75's. Maybe you're not reading the manual right. P.129 applies to 1YA00 which means all models. Coolant control calve is shown in the hose assembly.
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Team Owner
Joined: Aug 2006
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From: Columbia Missouri
Pro
Joined: Mar 2001
Posts: 633
Likes: 1
From: Hamilton, ON, Canada
I wouldn't put too much faith in NAPA. I got both the upper & lower hoses from them. They didn't have them in stock-had to order them in but said they were Gates. The upper hose was fine-had the Gates name stencilled on it & was a nice stiff rubber. The lower hose had no ID on it, was a bit on the soft side & didn't have the wire spring inside. The NAPA guy argued up & down that it was the correct hose but I know otherwise.
Race Director
Joined: Sep 2001
Posts: 10,560
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From: Wellington, FL
St. Jude Donor '11 thru '25
Last edited by Jud Chapin; Jan 21, 2007 at 11:35 PM.
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
I wouldn't put too much faith in NAPA. I got both the upper & lower hoses from them. They didn't have them in stock-had to order them in but said they were Gates. The upper hose was fine-had the Gates name stencilled on it & was a nice stiff rubber. The lower hose had no ID on it, was a bit on the soft side & didn't have the wire spring inside. The NAPA guy argued up & down that it was the correct hose but I know otherwise.
Napa, as well as most other stores...carry two grades of parts. They can GET the original correct hose, but HAVE a cheap repro with no spring and poor quality. A GOOD car guy employee would have just said we can order the correct hose and have it here by tomorrow. Sounds like you talked to someone from the shallow end of the gene pool.
Pro
Joined: Mar 2001
Posts: 633
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From: Hamilton, ON, Canada
I'm a little confused here and maybe you can help me out. Where do you see that 1YA00 means all models? I'm looking all over the manual and can't find the definition. Anyway, page 129 is a non a/c car. If you flip the page over to page 130, you'll see an a/c model with no valve which is the way my '75 a/c car came. There it says both 1YA00 and C60 for heater hoses. I know that C60 is the RPO # for a/c. Are you sure 1YA00 means all models? Take a look at page 132, for example, as it shows 1YA00 and it is a picture of a convertible top. Perhaps I'm misunderstanding something here. Anyway, thanks for the info and maybe you can straighten me out on this.
Pro
Joined: Mar 2001
Posts: 633
Likes: 1
From: Hamilton, ON, Canada
I'm a little confused here and maybe you can help me out. Where do you see that 1YA00 means all models? I'm looking all over the manual and can't find the definition. Anyway, page 129 is a non a/c car. If you flip the page over to page 130, you'll see an a/c model with no valve which is the way my '75 a/c car came. There it says both 1YA00 and C60 for heater hoses. I know that C60 is the RPO # for a/c. Are you sure 1YA00 means all models? Take a look at page 132, for example, as it shows 1YA00 and it is a picture of a convertible top. Perhaps I'm misunderstanding something here. Anyway, thanks for the info and maybe you can straighten me out on this.
Race Director
Joined: Sep 2001
Posts: 10,560
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From: Wellington, FL
St. Jude Donor '11 thru '25
Looking at the manual again, it seems there is an error in the designation on P.132. It says the convertible top is on both the coupe & convertible (1YA00). It should say 1YZ67. Refer to pages 81 & 82 which show windshield details for coupe & convertible. P.81 refers to 1YZ37 (coupe) while P.82 refers to 1YZ67 (convertible). Using that as a base, it seems that P.132 is in error. Note that the text on P.132 (top left) does refer to 1YZ67.
Last edited by Jud Chapin; Jan 22, 2007 at 05:12 PM.
Race Director
Joined: Sep 2003
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From: Database Error Indiana
1YA00 is defined on P.8. It does look confusing. P.130 definitely shows no coolant control valve for A/C cars. I conclude that non A/C cars like mine had a control valve while A/C cars had no valve. That must mean that "all models" refers to both coupe & convertible but then the designation on P.132 is confusing. My coupe didn't come with a convertible top. The only other explanation is that "model" referes to either coupe or convertible or there's an error/misprint in the manual.
I normally hang out in C4, but thought I would add my 2 cents here. In 1980 I bought a low mile 75 AC coupe. No control valve. I thought it was odd, so I added one. I currently have an 80, with one in each hose. I am not sure of the point in that either.
Race Director
Joined: Sep 2001
Posts: 10,560
Likes: 439
From: Wellington, FL
St. Jude Donor '11 thru '25
Yes, I'm not sure why they put one on a non a/c car but not on one with a/c. In any event, the a/c cars had one in '76. Out of curosity, how did you hook up the vacuum for the '75 switch? It should block the water flow only when the a/c is on as is the case with my '76.
Melting Slicks
Joined: Jul 2004
Posts: 2,577
Likes: 2
From: Long Island New York
Wherever you decide to buy your hoses from just make sure that the bottom hose yo buy has the spring in it or it will collapse on you and cause overheating problems. Also I would leave the valve in even though you don't want to use your heater because I think you may need it when you want to use your defroster's right? Doesn't the A/C compressor cycle on when you put on the A/C like in these newer cars? I don't know for sure because my car had the A/C removed from it before I bought it. The valve is in there but the vacuum line to it was disconnected so I replaced the valve and now I have all new vacuum lines to put in the system including the one to the valve. Am I wrong on this one, do I not need to do this?