Topic: Expansion Tank
in Forum: C3 Cooling and Heating Systems
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Let me see if I can explain this to anyone. The expansion tank is for the overflow of the radiator. However it also connects to the heater core.
The tank has two upper hose connections, and two lower connections. The way I understand from prior forums that the most upper connection hose will go to the radiator for the overflow. The next outlet goes to the overflow of the expansion tank and it is just a hose going towards the ground.
The other two hose connection will be for the 3/4 hose, or the larger hose coming from the water pump. In which this hose will be just cut in half and one end going into the expansion tank and the other end into the other side of the expansion tank which then heads up to the heater core. In other words the expansion tank sits in between the 3/4 hose (larger hose) that goes from the water pump to the heater core.
Sounds logical!
However what keeps the expansion tank from filling up completely and then overflowing through the expansion tank overflow???? The water pump continues to pump water towards the heater core through the expansion tank which then over fills.
So I have anti freeze all over the garage floor, with a near empty radiator.
Where did I go wrong, on installing this expansion tank????
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Rochester, NY - USA
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Vette(s): 1980 L- 82 fully restored and upgraded.
Your expansion tank is to handle coolant that expands as it heats up ... period ... that's it end of story . I have no idea why your putting it between the heater hose supply to the heater core, those hoses connect directly to the heater core interrupted only by a heater control valve.
|UPDATED|3/24/2013 6:08:12 AM (AZT)|/UPDATED|
|UPDATED|3/24/2013 6:08:12 AM (AZT)|/UPDATED|
1980 , ZZ430 , 3.92 rear , 700R4 2400 stall NEW EZ EFI
Go back to April 5th 2012 under expansion tank forum. That is what I went by, so with that in mind what would be the purpose of the two outlets at the bottom of the expansion tank if they didn't go to the heater core??
You might be thinking of just the engine cooling recovering tank. I am referring to the expansion tank which is aluminum on a 1968 through 1973.
Corvette Central Catalog show a picture of the expansion tank and shows the heater hose sets going to the tank, but no further explanation.
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Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/
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He's doing it like that because that's the way it's s'posed to be. The expansion tank goes in-line on one of the heater core hoses ...always has. I think the main question is, which hose to tie it into. I believe it should be in the hose coming from the intake fitting to the heater core. Since the two hoses are different sizes, the size of the fittings on the expansion tank should be a clue as to which section is used.
In this other thread , Bob said he had info on how it goes. Perhaps he will share again.
Rich, if you are getting coolant out of the expansion tank onto the floor, perhaps your cap is not doing it's job? The air that is in the tank should keep the coolant from leaking out unless either the engine is running hot, and/or the cap is not holding a seal. You might try a new cap first.
Someone here HAS to have a '68-'69 AIM that would clear up this confusion... Anyone?
|UPDATED|3/24/2013 8:04:08 AM (AZT)|/UPDATED|
In this other thread , Bob said he had info on how it goes. Perhaps he will share again.
Rich, if you are getting coolant out of the expansion tank onto the floor, perhaps your cap is not doing it's job? The air that is in the tank should keep the coolant from leaking out unless either the engine is running hot, and/or the cap is not holding a seal. You might try a new cap first.
Someone here HAS to have a '68-'69 AIM that would clear up this confusion... Anyone?
|UPDATED|3/24/2013 8:04:08 AM (AZT)|/UPDATED|
Joel Adams
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rlu1968 said: Go back to April 5th 2012 under expansion tank forum. That is what I went by, so with that in mind what would be the purpose of the two outlets at the bottom of the expansion tank if they didn't go to the heater core??
You might be thinking of just the engine cooling recovering tank. I am referring to the expansion tank which is aluminum on a 1968 through 1973.
Corvette Central Catalog show a picture of the expansion tank and shows the heater hose sets going to the tank, but no further explanation.
My bad
1980 , ZZ430 , 3.92 rear , 700R4 2400 stall NEW EZ EFI
The larger hose the 3/4 is the only heater hose that fits the expansion tank. I have a new cap on the expansion tank.
Somehow the theory is all bad. How can you pump water into a tank(a continuos stream of water fueled by the water pump) with one other outlet going to the heater core and not expect the tank to fill up faster than it is going out towards the heater core, thus spilling antifreeze out the overflow on the expansion tank. Why did the expansion tank in the small blocks even need to go to the heater core. I have a shut off valve coming and going from the heater core and they are both open.
Maybe the answer lies in the fact that I have a big block radiator, use to have a 427 engine, now i have a small block. The 427 did not come with expansion tank. I don't really see how this could make a difference though.
I liked the looks of the expansion tank, but can't see the whole picture on how it works.
Wow, I never realized those years had that. My LT-1 just has an overflow hose to the ground.
So why was it designed that way with the heater hose going through it? Doesn't make sense to me.
So why was it designed that way with the heater hose going through it? Doesn't make sense to me.
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#2-1985 Bright Red/Carmine Cp.L-98/auto
Member: NCRS, NCRS Texas, Corvette Legends of Texas
The design concept is similar to what you have in your water heater at home(or storage tank of a system with well water). There needs to be a space at the top that is nothing but air...a cushion of sorts. It also provides an amount of compression in the system. This is what keeps the tank from just filling all the way to the top with the engine running. As long as there is a specific, minimum amount of free air space in the tank, you should have NO leakage/spillage out of the tank under normal operating conditions. "Normal" meaning that the radiator does NOT also have a radiator cap on it, the cap on the expansion tank is holding the specified pressure, and the engine is not overheating.
Joel Adams
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(click for Texas-sized view!) NCRS
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These will help show how it is hooked up not sure it answers the question of operation will keep looking
http://www.C3VR.com/member_uploads/4201_4300/4221/71-AC-Heater-Hoses.jpg
http://www.C3VR.com/member_uploads/4201_4300/4221/expansion-tank-68-72-sm.jpg
Bob, thats interesting as they are marked 68-72 and 69-72. I have a 72 and dont have a tank like htat on mind. Does it just represent BB cars or maybe ones with AC? Mines a small block with no air. Hope it helps the original poster.
Rodney
Rodney
in Forum: C3 Cooling and Heating Systems
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