Topic: Possible to have too much coolant?
in Forum: C3 Cooling and Heating Systems
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Is it possible to have too much coolant in my system? I just purchased a 69 and the only problem I’ve really had with it so far is that on hot days it has purged a good amount of radiator coolant from the side discharge jug onto the ground.
The last time it happened I added more coolant and the car ran fine for a couple of days and then today it discharged again.
The car has a brand new radiator, water pump and thermostat.
Is this normal? Am I running too much fluid? I fill the discharge tank to about half.
Thanks
Eric
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Lifetime MemberYes, you can overfill the system.
If you have an overflow tank (discharge tank) you keep the radiator completely full.
But you need to leave some space in the overflow tank. Coolant expands when it gets hot, and it needs to go somewhere. If the tank is too full, yes it will dump some coolant on the ground.
As the system cools, it shrinks volume, creates a vacuum, and pulls coolant back into the radiator.
How full is the tank before it happens? How much is in the tank when it cools back off?
If you have a cap for a non overflow tank system, it will dump on the ground when the coolant expands. With the right cap, it should balance out the system.
When you fill to 1/2, is that with the engine cold or hot. Cold, it could be the issue. Hot should be fine at that level.
A weak pressure cap will cause the problem with a other wise good system.
Thanks for the reply.
The overflow tank says to fill half full when cold. I don't beleive the overflow tank was replaced when the new radiator was added in March. It sort of makes me wonder if the overflow tank is too small or too old for the new radiator. The cap looks fairly old and I am going to replace that either way but I am going to look into finding out weather I have the correct overflow tank for the current radiator I have.
Make sure the antifreeze is diluted properly. Mine was too pure antifreeze and it was like syrup and did not cool properly. Put the proper mix in and no problems since!
Barry
ANTIFREEZE DOESN'T DISAPATE HEAT AS GOOD AS WATER, IN THIS CASE MORE IS NOT BETTER, BECAUSE MY CAR IS KEPT INSIDE AND WHERE I LIVE I DON'T HAVE TO WORRY ABOUT EXTREME FREEZEING COLD I RUN 1/3 COOLANT, 2/3 WATER, 1 BOTTLE PRESTONE COOLING SYS LUBE, 25LB. CAP, NORMAL DAY RUNS 180-90, HOT DAY 112-115*WEATHER 210-220, HIGHER CAP PRESSURE RAISES BOILING POINT.
If your system is like the one on my '70 you should have an expansion tank (which is where you check the coolant level) and an overflow tank/bottle (which catches the excess coolant).
If things are running that hot check to make sure the fan shroud is in place and the gaps around the radiator are filled in. Sounds like there isn't enough air getting pulled through the radiator to keep things in balance.
Jim Olson 
"The Toys"...!!! Save the Wave! 
Derics Dad if your expansion tank reaches it't operating temp. and doesent doil over any more,or to a point that the tnak isempty you are ok ie:half tank usual.
however if you have the right cap [17lb] for an expansion tank and you still over heat ,look at all the gaskets around the rad. make shure they are all their .next make shure the fan shroud is pushed in as close to the rad. as possible.
If you are still having problems of boiling over I would have your fule air rachieo checked you could be running to lean
in Forum: C3 Cooling and Heating Systems
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