Is it worth it to replace the coolant in the overflow tank on a regular basis? I've heard of people doing this often rather than radiator drain and fills on longer intervals. Does all the coolant in the overflow tank get regularly circulated throughout the system?
Periodically draining and filling overflow tank
- Thread starter Corollaman
- Start date
This is not 1975 your thoughts are old school, no offense. LOL
Waste of time. Tank holds 1/2-1 quart vs. 6 to 12 or more quarts of coolant in the rest of the system plus it doesn't get regularly circulated throughout the system anyway.
I've never done it, just heard about it. I was born in 1975 though.
By definition an overflow tank is not pressurized, so there's only one way in and out. Whatever volume of coolant that regularly moves through the hose, a few teaspoons, is all you get.
A surge tank, OTOH, is more likely to see movement. Still the premise is stupid. Even draining only the radiator (not the block) and getting half the fluid is pretty lazy. That's a better procedure, though, because you're not dealing with potentially cranky block drains. If you insist on not draining the rad look into supplemental coolant additives and a base antifreeze chemistry that supports them. Only really seen on big rigs.
A surge tank, OTOH, is more likely to see movement. Still the premise is stupid. Even draining only the radiator (not the block) and getting half the fluid is pretty lazy. That's a better procedure, though, because you're not dealing with potentially cranky block drains. If you insist on not draining the rad look into supplemental coolant additives and a base antifreeze chemistry that supports them. Only really seen on big rigs.
The average age of the coolant is all that matters,
I do what you describe on a volt because flushing the system can permanently brick the car and the dealer doesn’t care.
Sadly on the volt the amount of coolant in and out is even smaller but after dozens of cycles (which is easy to do) will end up the same age as the rest in the system.
An antifreeze tester isn’t expensive and can answer if the stuff in the radiator is steady, aged out or still fine.
If your car is not prone to chugging air when you open the radiator cap you can do a fluid change Walmart style with a tube and suction.
Just remember you won’t clear the crud out of the bottom of the radiator which is some cases is good and others you get a plugged check valve
I do what you describe on a volt because flushing the system can permanently brick the car and the dealer doesn’t care.
Sadly on the volt the amount of coolant in and out is even smaller but after dozens of cycles (which is easy to do) will end up the same age as the rest in the system.
An antifreeze tester isn’t expensive and can answer if the stuff in the radiator is steady, aged out or still fine.
If your car is not prone to chugging air when you open the radiator cap you can do a fluid change Walmart style with a tube and suction.
Just remember you won’t clear the crud out of the bottom of the radiator which is some cases is good and others you get a plugged check valve
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Depends on the design of the cooling system. As others have said, it's not the best way to maintain your cooling system, but it's better than doing nothing.
The Northstar engine, for example, had a small hose that continuously bled coolant from the highest point of the engine (the throttle body) into the overflow tank. That hose ensured that no air or combustion gas accumulated in the block, contributing to overheat. It was sometimes known to plug off with debris unfortunately.
A system like that would get the overflow tank circulated regularly.
The Northstar engine, for example, had a small hose that continuously bled coolant from the highest point of the engine (the throttle body) into the overflow tank. That hose ensured that no air or combustion gas accumulated in the block, contributing to overheat. It was sometimes known to plug off with debris unfortunately.
A system like that would get the overflow tank circulated regularly.
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