Coolant expansion tank cap
12-10-2017, 07:11 PM
#1
Thread Starter
Join Date: Sep 2015
Location: Michigan
Posts: 6
Coolant expansion tank cap
So my plastic cap broke in half and when I tried getting the other half out plastic pieces broke and fell into the tank. I'm looking at buying an aluminum tank but I don't want to get another plastic cap. Does anybody know where I can buy a metal/aluminum coolant expansion tank cap?
12-10-2017, 11:50 PM
#2
3rd Gear Member
Join Date: Jul 2017
Location: AZ
Posts: 849
So my plastic cap broke in half and when I tried getting the other half out plastic pieces broke and fell into the tank. I'm looking at buying an aluminum tank but I don't want to get another plastic cap. Does anybody know where I can buy a metal/aluminum coolant expansion tank cap?
The plastic tanks used are pretty indestructible. The caps may not be. Do you understand that the caps so-used are actually "radiator caps", in that they do not relieve pressure until boiling occurs, which is rarely encountered?
The older systems "bled" expanded volume of coolant out of the radiator and into a NON-PRESSURIZED catch bottle. Then, upon cool down, the shrinking volume of coolant within the engine "sucked" the overflowed liquid back into the engine. The new system merely uses an "extended" part of the radiator, the "expansion tank", to accumulate the excess liquid UNDER PRESSURE, and return it to the engine upon cool-down.
The newer idea was used as far back as 1958-1960s by Ford. Those had a nice brass tank bolted to the thermostat housing on the intake manifold, through which the coolant was directed to the radiator.
This all stems from the fact that as the coolant heats up, it expands. If the closed cooling system has no place in it for the excess coolant to reside, it's pushed out to sit in a "catch bottle", until the engine is shut down, cools off, and the shrinking coolant within it draws the excess back past a valve built into the radiator cap and into the engine again.
Many years ago, hoods were very high, space was not at a premium, all radiators were of the "downflow" type, and the top of the radiator had a very generously-sized tank which served as the "expansion-tank". No coolant ever escaped unless boil-over occurred. No tricky rad. caps. were needed. Best of all, everything was sized BIG enough to get rid of all that heat.
Cross-flow radiators made things more difficult. They allowed little, if any, volume for "expansion space". Thus the need to aderquately accomodate them. 'Course, the cross flow COULD be left low-filled, with a space up-top to accomodate expansion, but doing so would "waste" heat transferring tubes and fins not exposed to liquid-fill. imp
12-11-2017, 12:09 AM
#3
Thread Starter
Join Date: Sep 2015
Location: Michigan
Posts: 6
Year and model? Is it a true expansion tank, in which the cap is actually the pressure-relieving "radiator cap"? Does your radiator have any kind of removable cap?
The plastic tanks used are pretty indestructible. The caps may not be. Do you understand that the caps so-used are actually "radiator caps", in that they do not relieve pressure until boiling occurs, which is rarely encountered?
The older systems "bled" expanded volume of coolant out of the radiator and into a NON-PRESSURIZED catch bottle. Then, upon cool down, the shrinking volume of coolant within the engine "sucked" the overflowed liquid back into the engine. The new system merely uses an "extended" part of the radiator, the "expansion tank", to accumulate the excess liquid UNDER PRESSURE, and return it to the engine upon cool-down.
The newer idea was used as far back as 1958-1960s by Ford. Those had a nice brass tank bolted to the thermostat housing on the intake manifold, through which the coolant was directed to the radiator.
This all stems from the fact that as the coolant heats up, it expands. If the closed cooling system has no place in it for the excess coolant to reside, it's pushed out to sit in a "catch bottle", until the engine is shut down, cools off, and the shrinking coolant within it draws the excess back past a valve built into the radiator cap and into the engine again.
Many years ago, hoods were very high, space was not at a premium, all radiators were of the "downflow" type, and the top of the radiator had a very generously-sized tank which served as the "expansion-tank". No coolant ever escaped unless boil-over occurred. No tricky rad. caps. were needed. Best of all, everything was sized BIG enough to get rid of all that heat.
Cross-flow radiators made things more difficult. They allowed little, if any, volume for "expansion space". Thus the need to aderquately accomodate them. 'Course, the cross flow COULD be left low-filled, with a space up-top to accomodate expansion, but doing so would "waste" heat transferring tubes and fins not exposed to liquid-fill. imp
The plastic tanks used are pretty indestructible. The caps may not be. Do you understand that the caps so-used are actually "radiator caps", in that they do not relieve pressure until boiling occurs, which is rarely encountered?
The older systems "bled" expanded volume of coolant out of the radiator and into a NON-PRESSURIZED catch bottle. Then, upon cool down, the shrinking volume of coolant within the engine "sucked" the overflowed liquid back into the engine. The new system merely uses an "extended" part of the radiator, the "expansion tank", to accumulate the excess liquid UNDER PRESSURE, and return it to the engine upon cool-down.
The newer idea was used as far back as 1958-1960s by Ford. Those had a nice brass tank bolted to the thermostat housing on the intake manifold, through which the coolant was directed to the radiator.
This all stems from the fact that as the coolant heats up, it expands. If the closed cooling system has no place in it for the excess coolant to reside, it's pushed out to sit in a "catch bottle", until the engine is shut down, cools off, and the shrinking coolant within it draws the excess back past a valve built into the radiator cap and into the engine again.
Many years ago, hoods were very high, space was not at a premium, all radiators were of the "downflow" type, and the top of the radiator had a very generously-sized tank which served as the "expansion-tank". No coolant ever escaped unless boil-over occurred. No tricky rad. caps. were needed. Best of all, everything was sized BIG enough to get rid of all that heat.
Cross-flow radiators made things more difficult. They allowed little, if any, volume for "expansion space". Thus the need to aderquately accomodate them. 'Course, the cross flow COULD be left low-filled, with a space up-top to accomodate expansion, but doing so would "waste" heat transferring tubes and fins not exposed to liquid-fill. imp
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