Back in October I needed to replace the leaking radiator in my new wagon. Before I did so, I thought it would be a good idea to at least flush out the old coolant at the same time. I pulled the block drain plugs as well as pulled the lower radiator hose. When that all drained out, i reattached the lower hose, left the plugs out and flushed plain water through the radiator until it came out the drains on the block. I did this with the engine off and the heater in the cold/off setting. When that finished, I reinstalled the drain plugs and removed the radiator. The block has been empty since. Fast forward to today. I just got the new radiator I ordered after a failed attempt on getting the old one recored(that's a whole other story). Since October the temp here at times has dropped to approximately 10F, and the car is outside. As I was excitedly getting ready to put in the radiator- it occurred to me: Is it possible that plain water got into/filled the heater core, or is it more likely that it still contains old coolant where I had the engine and heater off? I have horrible luck, so I am quite concerned that I'll get it all back together and I will find that the core has ruptured as well. Any thoughts would be appreciated!
If the heater valve was off I would think that antifreeze would still be in it. If temps never got below 10 degrees it may have not frozen water in the core anyway. Only way to find out is first put plain water in radiator to check so you don't waste more antifreeze just in case of a leak.
That is what I am thinking/hoping- the one hose without the valve does connect it to the water pump, and I was concerned with the water I flushed through the block/water pump might have displaced it. I will do that with the water instead of antifreeze for the initial test. That and I would hate to dump antifreeze on the freshly shampooed carpeting in case of a leak.
I think you shold be ok because the water would have room to expand, hope it works out ok for ya BigBird, keep us posted .
As far as I know, there is no actual valve on the hoses leading to the heater core, its all on the "flapper" or door that directs air over the heater core. With this in mind, you probably flushed the coolant from the heater core. The only thing that could save you with this is that you did have an open system. When it started freezing, it did have room to expand and maybe not blow out the core. I would try to flush or thaw out the heater core first because even if it didnt burst open, you may have an ice cube there restricting the water flow. Try and get the car into a garage and let it warm up for a coupel days and check it then if possible.
DLC all heaters, from way back, have some sort of inline water valve. May be manual, vacuum, or electric but there is one in line in the hose. I still wonder if just because there may be an open heater hose that the core still couldn't freeze and expand! Only way to know is blow air through it or water.
The OP's car may or may not have a heater core water valve. I know for sure that none of my FWD GM cars from the 80s and early 90s have had one. Coolant always flows through the core, and there is simply an interior flapper to redirect the airflow as needed.
In the case of the 307 in my Caprice, it does not have a water valve. My concern is where I filled the radiator is that the water filled the block from the bottom up while flushing, and as it traveled through the water pump, it entered the return line and back-filled the core. As it has been snowing here and I don't have a garage, I have to wait before I do anything really. I am tempted to go out and pull both heater hoses and look in the core to see if I can see anything. Also, where it won't consistently be above freezing here for some time, I was contemplating pouring some straight alcohol into the core, to melt any ice if it has formed, and to cause a leak, if any has formed- that way I can be prepared to pull the core come warmer weather, rather than having it all buttoned up before I discover any damage.
I couldn't take the not knowing anymore so I went outside just now and removed both heater hoses- no ice to be seen. Since my compressor is in the basement, and using plain water in these temps (approx 20F) is out- I attached a hose to one side and started to pour in a quart can of denatured alcohol. I poured approximately 1/4-1/2 of the can and nice, green coolant started to come out the other side . I think I might have dodged a bullet on this one. I'll know for sure once it's reassembled and pressurized, but this is definitely promising.
You lucked out this time. Should be just fine till spring. Now think of something else to worry about. There's always something with motor vehicles. :banana: I laid awake nights thinking of scary things like your heater when I worked on my cars. Actually gone out to the garage at nite in cold weather in my jammies to check.
My thoughts exactly! I don't plan on driving it until spring, after the salt/snow is gone. Now, if only I could get the free time to put the radiator back in... I seem to be in a perpetual state of automotive worry- glad it's just not me. My wife just tends to stop listening when she realizes it's car related. Seeing as I want to take all around New England and to North Carolina this summer- I figure this kind of worry is needed.
To me the cooling system is the most important part of enjoying any older vehicle. Of course the steering and brakes are more important. But overheating seems top on the worry list. Back in around 88 I put a large big block 70's cross flow radiator in the 55 wagon. Overkill and too much work. But it worked till last year when it finally deteriorated. Son had put a $100 single core replacement aluminum radiator in his 76 El Camino with AC. It worked great. So I gave him $100 and he went to his favorite Disc. Parts Store and got another which pretty much was same sizes as the old 4-core 70's radiator. Wouldn't ya know the wagon actually runs cooler! Electric duel fans rarely kick on. Drove 140 miles each way in summer heat and they came on briefly twice in city traffic. Wait till this summer with AC to really test it.
That's really impressive- I wouldn't have expected those kind of results from a single core radiator, especially an aluminum one. I was under the impression that the older brass/copper models transferred heat better. I'll definitely keep that in mind for another time My other Caprice, also a 307, gave me huge problems with the cooling system, from a defective replacement radiator, to a leaking intake manifold gasket, worn out water pump, block clogged with rust scale and finally a failed fan clutch. It took me most of last year to get that one sorted out. So I definitely worry about cooling thanks to all of that! This one is a lower mileage one, No A/C with the original leaking two row radiator that I pulled to have recored. That was incorrectly done, and it now no longer fits the car- it is too long. I ended up going to the Chevy Dealer and was still able to get an NOS radiator, cheaper than what I paid to have the old one re-cored. Next is replace the four blade fixed fan with a five or seven blade clutched fan, thermostat, belts and hoses. The water pump was replaced at 78K- in 1995. The car has 91K on it now. I can hardly wait to drive it as my other Caprice is very tired and rusty.
The single core aluminum radiator still amazes me. If son hadn't just put one in his modified El Camino 350 I would never even considered it. What clinched the deal was Disc Auto said bring it back if it doesn't cool. Under $100 with tax at the time. Old one scrapped around $50. I was told that copper/brass and a zillion cores was the way to go. But thinking about it, plenty of inlet air and a good fan is what counts. All of those above problems are what we've all been through. I swear by a good electric fan now. Found out if there is enough incoming air and a good waterpump, the fan is on very little. I set switch to 180 and run 180 thermostat. Think about it, at idle the mechanical fan is only turning very slowly. I go to swap meets and buy mostly new take-off electric fans in a shroud. Now runinng T-Bird two speed fans in the two pictured cars. Opps forgot, no longer show 1941 Ford with 350 Chevy and 57 Chevy radiator.
