Hi I have bought a new heater core for the 76 Electra. Does anybody have any tips about the easiest way to replace it?
Start taking the car apart because I think it's located behind the dash. That's where the coolant hoses lead to anyways. You don't need to drain the radiator the whole way, even though the manual will probably tell you to. Have old towels available. Good luck. Are your windows fogging up? The heater core in my '76 also needs to be replaced as I think it is partially plugged. The fitting sizes on the heater core are 3/4" and 5/8" right?
Hi I cant see any leaks, but there is almost no heat, its good enough in the summer time, but too cold when temperature is bellow zero. I don't know about the fitting sizes, I have to check it up. And the only place there it's really coming any heat, is the vents that is on the middle of the dash, not up or down. There is also something wrong with the fan circuit, looks like it only function on the slowest position.
Feel the inlet hose for the hot water that feeds the heater core. If it is not hot then it is the heater control valve.
Hi But its really worth it,they charge you about 90$ a hour at shops here in Norway and they aren't familiar ,working on us cars either.
It isn't a hard thing to do, but annoying. You might have a bad blower automatic relay, if the fan only functions on the slow speed. I'll post a picture later, or you might already know where it is. Be careful taking the dash pad off. Everything else is easy to remove. You might not even need to do that.
Hi A picture would have been great. :TU: If I connect a positive lead directly to the fan,it blowes like h... So it could be the blower automatic relay.
If I remember correctly, the red circle is the automatic relay, which controls the higher speeds and the blue circle is the low blower relay. Disconnect one and see what fan positions work, then use process of elimination to see what is going on. Well, this is all assuming that you have automatic climate control (ACC) Most Electras did. I put a switch on my blower motor so I can actually turn it off. In the off position the blower motor still runs at a very low speed, as part of the full flow ventilation that was in all 76 Buicks. Let us know.
I would try backflushing the heater core before replacing. Only downside is you may cause a leak where none previously existed. John :beer
Hi I can't see any leak,but sometime's I do have a little coolant smell in the car and since i allready have bought a new core,it will be ok with a new one.
On my '75, the heater core suddenly blocked 4 years ago and there was no heat coming from it. Flushing it with water and some compressed air corrected the situation and now the heater works very well and never leaked since. Since you smell coolant in the car and you already have a new heater core, I understand you'll prefer to replace it immediately. In my '75 there is no space there because of the passenger side airbag but since your car doesn't have this option, it should be removed easely. There is no heater control valve on the 1976 full size Buicks, the 1975 and older ones have one but it was deleted on the 1976 models (at least those with ACC). This means that the coolant should always be circulating in the heater core when the engine is running, even with the a/c set in maximum cooling position. About your blower, if your car has the Automatic Climate Control (less than 40% of the 4 dr. Electra Limiteds had it in 1975 and many 1976 Electras lacked it too, but I think yours have it, right?), there could be something wrong with the programmer if you get only one low blower speed and the air only comes from the a/c outlets. A bad blower relay wouldn't allow the blower getting into maximum speed but the four other fan speeds would still work with the selector lever in "economy" or "auto" positions. What happens when you set your a/c to defrost? The air still comes from the a/c outlets and not the defroster outlets? If that's what's happening, first, have a look at your vacuum connections. A 1976 Buick chassis manual will help you finding out how it works. If the blower doesn't operate at all with the a/c selector lever in any position with the engine warmed up, it could be caused by a bad inline fuse wich is located on a red wire near the programmer on the passenger side. Normally, the blower should be constantly operating when the engine is warm and the ignition switch is ON, even with the ACC selector lever in OFF position. In the OFF, and LO position, the blower should stay in low speed. On the ECONOMY, AUTO and BI-LEVEL positions, the blower speed should vary depending of the difference between the actual temperature inside and outside the car and the temperature setting on the control panel. On the HI and DEFROST positions, the blower should stay at it's higest speed, even when the engine is cold in the DEFROST mode. So far, the only problems I had with the 1975-76 ACC systems were a dirty connection at the exterior temp sensor which mixed up the programmer that was in maximum heating mode even with a/c set to 65f. Cleaning the connector corrected this problem in just a few minutes. The other problem was the dirty connectors for the inline fuse in both my 76 and 75 which caused the fuses to overheat and burn even if they still looked good when checking the filament through the fuse glass. I never had to mess with the MK II programmers in my 1975-76 Buicks, they are quite reliable compared to the earlier systems. But even reliable parts could go wrong on a 30 years old car.... If you could describe exactly what your heater a/c does in every mode, temp setting and with the engine cold and warmed up, this would help us to isolate the problem(s).
You should only get heat out of the dash vents when the ACC is in bi-level and economy. If you get heat out of the dash on any other mode, you have a vacuum or programmer problem. You should get heat out of the heater outlet, when on the hi low auto and a little in the defrost position, when the temperature dial is at 85. I have never had any problems with my programmer (the Mk II that Phil talked about). The only problem I have had was with my auto relay (extremely corroded, sprayed with LPS-1) and the inline fuse that Phil mentioned. There are only 4 or 5 parts to the programmer, and it is a servicable unit. I pulled mine out of the car a while back, thinking I had a problem with it, but I couldn't figure out how to open it up, and I didn't want to force it open. You can buy the Mk II on eBay. The relays work by grounding the system which allows the blower to operate.
Did you ever get the core replaced? I bought one yesterday and I need to install it. Did you take the dashpad off, or were you able to get at the core from underneath?
Hi Because of my bad health, I haven't done it yet. It's not so much work, to remove the dash pad, and I am not sure if it's necessary, but it will anyway help you to get a better overview.
There is a steel brace that runs from the firewall to the dash. That brace must be removed along with the heater box because it is one piece, and goes around the top, and bottom of the box. No need to remove pad. Just remove the lower steel portion below the clock. Bolts for it are under the simulated woodgrain plastic piece. Then remove the glovebox by letting it fall out from the back. Pulling it through the door will nearly destroy it. Access is pretty good after removing the above mentioned items. I have had to replace the core in both of my hotrodded 76 LeSabres. I had to restrict the coolant flow on the supply side of the core up at the intake fitting so that 6500RPM shift points would stop blowing them up. The first time it happened I figured it was one of those weird one time things. It happened again though and it is very messy when they rupture all at once. No problem in either car since.
The lower trim will definitely be removed. I was thinking about doing it on Thursday after school if the weather is nice. I looked in my shop manual last night and they show some good pictures of the B-C-E body heater system, but the picture is not from a C-body. It is close enough to work though. Buick recommends using a sealant around the housing of the heater core to block any air leaks. Did you do this as well? I never used sealant on my Continental, but it was in an easier location.
I'm gonna do the swap today, I'll make sure to take lots of pictures. It would be nice to have a thread with "common replacement parts" with good articles on how-to, organized by year and model.
