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Car Forum / Chevrolet / Chevrolet Corvette / December 2007New 1976 Owner with Limited Skills
Group - I just bought my first Corvette -1976. I have no experience with working on cars at all, but am a fast learner. I drove it home last night and found out that the heat doesn't work. I'm not sure where to begin to search for the problem. Is this something that I can fix myself or should I take it to a mechanic? For diagnostic purposes - the fan blower works and both dials on the control panel move and air flows both at the top and bottom. I put it on defrost, heater, and vent and had the same frigid results. Any help will be appreciated... > Group - I just bought my first Corvette -1976. I have no > experience [quoted text clipped - 14 lines] > > Any help will be appreciated... what about the temp slide bar ? Does it work ? are you sure that the heater core has NOT been bypassed ?  Signature'Key ===== The temp slider does move, but I don't know if it's doing anything. Is there an easy way for me to tell if it's actually moving the proper door? As far as the heater core being bypassed...I have no idea and don't really even know what that means, so any enlightenment would be helpfull!!!! Thanks Signature'Key ===== > The temp slider does move, but I don't know if it's doing > anything. > Is there an easy way for me to tell if it's actually > moving the proper > door? you should be able to hear it working the door. if the cable is broken you should feel nearly no tension on the slider and hear nothing. > As far as the heater core being bypassed...I have no idea > and don't [quoted text clipped - 3 lines] > > Thanks sometimes when a heater core goes bad (leaks) folks will bypass the heater core. you can look under your hood and see the heater hoses. the heater core is located on the passenger side if your car. follow your heater hoses, from you water pump, and see if they go directly in and out of the fire wall where the heater core is located. if the heater core was bypassed? you should see the bypass. g'luck -- 'Key Here's some diagrams that might help you understand what's in your car: http://www.docrebuild.com/dr-r-web/AC-VAC2.PDF Look at the diagram at the bottom center of the page and note the unlabeled device at the top of the picture... that's a metal diverter valve that sits in the engine compartment and has heater hoses connected to it. The heater hoses are attached to the nipples shown at the top and right coming out of that valve, the small hose shown as white in the diagram is a vacuum hose that actuates the diverter valve to send hot water through to the heater core under the dash when you turn on the heater, or to bypass the heater core and send the hot water back to the engine. note: This particular picture shows a system without a/c, but I believe that same valve is present on cars that DO have a/c as well, but they just don't show it on the a/c diagram (upper left on the page), they only show the airflow door actuators. I don't have a C3, so I can't verify that. That valve can stick or become disconnected from the vacuum hose, or there could be a leak in the vacuum system that prevents sufficient vacuum from reaching the valve. It is a common point of failure. The valve is not particularly expensive to replace. It could be checked by applying vacuum directly to the valve to see if the heater then works (you should be able to feel that the water hose from the diverter to the heater is cool before vacuum is applied, then heats up with vacuum applied). You may need a vacuum pump to test with, or you can "borrow" vacuum from another vacuum source on the engine by "Tee"ing into that good vacuum source. (Simply sucking on the hose orally is not likely to produce sufficient vacuum.) You could also disconnect the two water hoses from the diverter valve and clamp them to opposite ends of one short section of copper tubing (5/8" I believe) to bypass the valve for the winter, then reattach them to the diverter valve in the spring. Good luck. Well, I may have lied a bit...after some reflection, I think what I called the "diverter" valve simply stops water from passing through to the heater, rather than diverting it back to the engine. > Here's some diagrams that might help you understand what's in your car: > http://www.docrebuild.com/dr-r-web/AC-VAC2.PDF [quoted text clipped - 44 lines] > > Good luck. > Here's some diagrams that might help you understand what's in your car: > http://www.docrebuild.com/dr-r-web/AC-VAC2.PDF [quoted text clipped - 44 lines] > > Good luck. wow...thanks for the detailed answer. I'll check that out tonight when I get home... > Here's some diagrams that might help you understand what's in your car: > http://www.docrebuild.com/dr-r-web/AC-VAC2.PDF [quoted text clipped - 44 lines] > > Good luck. To all that helped me out I thank you... So from reading past posts, I am going to install the manual valves on the hoses as I think the vacuum control valve might be stuck in the closed position or something as I am not getting any flow to the heater core. One last question to everyone about this...do I need to drain the coolant level down to close off these valves in the summer? Also, when they are shut off, how can I make sure the heater core is not going to rust while it is not being used? In other words, do I drain it somehow when I close off the manual valves? Or does the water just stay in there all summer? Thanks again!!! > To all that helped me out I thank you... > [quoted text clipped - 19 lines] > > Thanks again!!! you should get the flow going to the heater core first. then don't drain the core. just simply open the valves from time to time to circulate the coolant through the heater core. g'day Signature'Key ===== > > To all that helped me out I thank you... > [quoted text clipped - 31 lines] > > - Show quoted text - So I replaced the vacuum valve with a manual one and now I have heat. The old valve was all gunked up and plugged, so I thank everyone that helped me! > So from reading past posts, I am going to install the manual valves on > the hoses as I think the vacuum control valve might be stuck in the [quoted text clipped - 9 lines] > > Thanks again!!! Did you price a vacuum valve? I think they are pretty reasonably priced. Why be fiddling with a valve under the hood when you don't have to? The heater core is made of aluminum (or possibly copper)... assuming that you keep a 50/50 mixture of water and quality anti-freeze in your cooling system and drain/refill every 3 to 5 years, with no leakage in the system in between refills, then no "rusting" or other deterioration should occur (it's just like leaving Pepsi in the can), so no need to drain the heater core. > > So from reading past posts, I am going to install the manual valves on > > the hoses as I think the vacuum control valve might be stuck in the [quoted text clipped - 18 lines] > (it's just like leaving Pepsi in the can), so no need to drain the > heater core. I did look at a new vacuum valve, but it's not price that made me go with the manual valves. The original valve didn't have any vacuum line hooked up to it and I couldn't find one that wasn't being used, so I would have had to fix the vacuum problem and I just wanted to get the heat working. Besides that, most of the forums that I have read, say that the manual valves are better in the hotter days because it cuts off the supply of hot water to the heater core and makes the interior cabin much cooler. I know it's not stock or original, but I can always go back to that if I want or need to do so. Thanks for the reply!!! > -- > 'Key [quoted text clipped - 31 lines] > -- > 'Key Thanks...I don't think it was bypassed, but not sure. I actually don't even know where the heater core is located...I assume it's behind the firewall??? So if you have the time, can you get more detailed and tell me how to check this as I have replaced the thermostat and made sure it has enough coolant. I'm pretty sure it either a hose or heater core problem of some sort. I wouldn't know what the bypass would look like. I can't even find the damn water pump. I bout a new one, but my future father-in-law says that I would know if it was bad as it would be noisy and the car would overheat. So I need to find that so I can follow the hoses to the heater core? The guy at Autozone said that I should try to clean/flush out the cooling system...to try to clean out any gunk or rust that may be in there???? I bought a kit and a solvent to flush it with, but don't want to go throughg the trouble if I don't have to....???? It would be a cheap fix if it worked... Is the heater core hard to get to??? Thanks for your help... > Is the heater core hard to get to??? The other possible solutions are much easier to try. I've done the heater coil, A/C, and pretty much everything else on my 1982. The heater coil fits through the firewall. The first step in the repair manual is to remove the seats, dash, and everything over the interior part of the heater coil. The second step involves removing the parts in the way under the hood. A good mechanic will charge about $500-700 for the day it will take to replace it. Start by finding a repair manual for your 1976. David > > Is the heater core hard to get to??? > [quoted text clipped - 8 lines] > > David I bought the C3 (it says like 1966-1976 Shop Manual in red on the cover) Shop Manual, but am very disappointed in the content. What are the best shop manuals out there? > I bought the C3 (it says like 1966-1976 Shop Manual in red on the > cover) Shop Manual, but am very disappointed in the content. What are > the best shop manuals out there? I have both the 1982 Shop Manual and Chilton's. They do leave much to be desired. My mechanic subscribes to the Mitchell Repair Manuals as well as many others. Perhaps Mitchell has a limited distribution you could buy. I'd suggest finding a local mechanic (Master Auto Technician) and asking him/her. They will likely help describe the process or let you look at manuals. My mechanic would let you do it yourself, off hours, with his tools for a pittance. David >> I bought the C3 (it says like 1966-1976 Shop Manual in red on the >> cover) Shop Manual, but am very disappointed in the content. What are [quoted text clipped - 9 lines] > > David my local library subscribes to the mitchell database. one can use it for free at the library. regards, charlie cave creek, az >> > Is the heater core hard to get to??? >> [quoted text clipped - 12 lines] >cover) Shop Manual, but am very disappointed in the content. What are >the best shop manuals out there? The GM shop manual is the only manual I've ever found that worth buying. The others skip to much material or leave key steps and areas "unexplained".. ----------- Elbert ask@me.com > On Wed, 5 Dec 2007 17:19:24 -0800 (PST), 1976VetteGuy > [quoted text clipped - 24 lines] > > - Show quoted text - Where can I get the GM shop manual? >> <mont...@gmail.com> wrote: >> >> > Is the heater core hard to get to??? [quoted text clipped - 24 lines] > >Where can I get the GM shop manual? http://www.helminc.com They are relatively expensive but it you have a car you plan to keep and would like to learn about the car or do the work yourself. The GM shop manuals are the best. A 76 corvette would be for the most part basic stuff, but everyone has to start somewhere. A GM shop manual is a good investment. You might hunt around E-Bay too. I would not waste my money on a CHILTON or Haynes unless that's the only thing you can get. ----------- Elbert ask@me.com > On Thu, 6 Dec 2007 17:26:06 -0800 (PST), 1976VetteGuy > [quoted text clipped - 44 lines] > > - Show quoted text - Thanks...would this be what I need? "1976 Passenger Car Shop Manual Set" >> <mont...@gmail.com> wrote: >> >> On Wed, 5 Dec 2007 17:19:24 -0800 (PST), 1976VetteGuy [quoted text clipped - 46 lines] > >"1976 Passenger Car Shop Manual Set" it would appear so. Thats what I see when I go to the site and run the lookup. I've bought some manauals from them in the past but they were for newer model vehicles. I would get the GM shop manual from Helms, and it might be worth you while to do some searches on Ebay for corvetter specific GM shop manauals. The GM shop manual would certainly be very helpful. They are not hard to use and are very well written and illustrated fairly well. Take it from me, some of the other manuals are just plain garbage. I believe you can subscribe to Alldata and maybe other sources for shop manuals "on-line" but that might get a little expensive for a @home mechanic. Any GM vehicle I own or want to know more about in regard to repairs....the GM shop manual is the best source for information. ----------- Elbert ask@me.com >> <mont...@gmail.com> wrote: >>>>>>> Is the heater core hard to get to??? [quoted text clipped - 36 lines] > > "1976 Passenger Car Shop Manual Set" Yes. P/N ST32976K $ 75 from Helm (probably a Xerox copy of the original.) Includes several other Chevrolet models. I'd not throw stones at adding a Chilton or Haynes to your library shelf after you get the factory manual. Sometimes those books will have a shortcut that may be helpful to someone who hasn't been through formal factory training or isn't too experienced. Sometimes Haynes will have a procedure that avoids use of a special tool. Example: On the C4, the factory manual procedure for removing the fuel pump is an involved project. The Haynes manual makes the job easier and quicker. -- pj http://www.ncrs.org/store/shop.cgi/page=C3.Library.htm/SID=1197050020.23908 (look about halfway down the page) > http://www.ncrs.org/store/shop.cgi/page=C3.Library.htm/SID=1197050020... > (look about halfway down the page) Are you talking about this thing? "1966-82 Corvette Shop Manual" If so...I bought it and it sucks... >> http://www.ncrs.org/store/shop.cgi/page=C3.Library.htm/SID=1197050020... >> (look about halfway down the page) [quoted text clipped - 4 lines] > > If so...I bought it and it sucks... Then buy the GM chassis service manuals (but the '74 base manual is out of print, so you'll need to find a used one). http://www.antiqbook.com/boox/nort/625a5689.shtml http://www.biblio.com/details.php?dcx=16721582&aid=frg http://www.rarenonfiction.com/?page=shop/browse&category_id=60 You are probably not going to find one perfect book that covers everything you'll ever want to know, specific to only your year. I don't have the one that claims to have excerpts from the GM manuals that cover "full maintenance, repair, troubleshooting and tune-up information" It sounds good... so help educate the rest of us: why/how does it suck? > http://www.ncrs.org/store/shop.cgi/page=C3.Library.htm/SID=1197050020... > (look about halfway down the page) OK...so I've figured out that the hoses running into the heater core aren't hot when the engine is at temp. So there's a flow issue somewhere. I also noticed that the hose running from the engine block, I believe, goes into the A/C box and is attached by a vacuum actuator valve that appears to have the vacuum line cut. Is it typical to have this valve in the line, and if so, where can I trace to where the hose should go to supply the vacuum? Will this cause the flow problem to the system? Last question...what causes the actuation to happen to the valve in the water loop? What's the temperature gauge read? > Group - I just bought my first Corvette -1976. I have no experience > with working on cars at all, but am a fast learner. I drove it home [quoted text clipped - 7 lines] > > Any help will be appreciated... Signaturespacecowboy@wahoo.org > What's the temperature gauge read? > [quoted text clipped - 12 lines] > -- > spacecow...@wahoo.org The temperature guage reads pretty low. It barely creeps up, but I don't even know if it works or not... This group rocks! Thanks to everyone so far...good stuff! VetteGuy: Actually I am betting that the heater has been bypassed ... Honestly these cars do not get driven in cold weather much anymore and can get really "warm" inside in the summer... so many ...if not most.. owners bypass the heater.. BUT ... I would check out the C3 registry (www.c3vr.com) and take a free ride for a month or pay all of 10 bucks for a years membership... Honestly it is the absolute best source of info(AND FREE ADVICE) on 68-82 Corvettes ..I own 3 C's and am a LIFETIME menber ONLY because everytime I had a problem I GOT ANSWERS... Enjoy the car.... and BTW...they are very simple to work on... mo high teck computers ...only real problem that the very first step to do any repair usually is DISMANTLE THE ENTIRE CAR... LOL Seriousl check out the registry...its full of forums that deal with everything from electrical to mechanical problems.. I did not drop the money to become a lifetime menber just for the fun of it...I got so much help with my first C3 that I saved lots of Time BUT also lots of money... Bob G. 64 72 & 98 Convertibles 76 & 79 Coupes... ============================ >> What's the temperature gauge read? >> [quoted text clipped - 19 lines] > >Thanks to everyone so far...good stuff! Well it may be as simple as manual heater control valve that's in line on the heater hoses. You turn it off in the summer and on in the winter. Whomever designed the nice heater setup on the 70's GM products needs to go back to school, I'm sure that person is most likely not around any more. My 78 Z28 pumped hot air into the car in the summer when the A/c was not on. I finally got tired of that and installed the above referenced manual heater control valve. I don't believe that the camaros or corvettes had a vaccum or other type heater control valve on the heater hoses during the late 70's. (1) check to see that the heater hoses are connected to the firewall, there are two. (2) check coolant level to make sure car is full. (3) let engine run and get to operating temperature (what is that temp?) (4) check to see if both heater hoses at the fire wall are hot...after engine runs a while. (5) check to see if previous owner installed a manual heater control valve or "by-passed" the heater core. (6) if all good above....then look for issues with the A/C -heater control head, broken cables, broken temp door, etc. I'm not sure on that model but it may have vaccum operated heater and A/C temp door controls, or it may be the old school pure manual setup. You have to "have" hot coolant at the heater core....for heat, that's the first thing to verify. >VetteGuy: > Actually I am betting that the heater has been bypassed ... [quoted text clipped - 48 lines] >> >>Thanks to everyone so far...good stuff! ----------- Elbert ask@me.com If the temperature gauge is reading low, you may need a new thermostat. Replace it. Costs less than $20. You need the engine to be at working temperature before you'll get any heat. >> What's the temperature gauge read? >> [quoted text clipped - 19 lines] > > Thanks to everyone so far...good stuff! Signaturespacecowboy@wahoo.org >Group - I just bought my first Corvette -1976. I have no experience >with working on cars at all, but am a fast learner. I drove it home [quoted text clipped - 7 lines] > >Any help will be appreciated... Do three things. No particular order. 1. Find your local Corvette Club. They're everywhere ask the local Chevy dealers. A lot of them meet there. 2. Buy a Chiltons or similar. 3. Get a decent entry level set of tools, I suggest Sears on that one. SignatureIf life is a waste of time, and time is a waste of life, then let's all get wasted together and have the time of our lives. |
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