Coolant fill max level

IMAGING

MEMBER
2005 TOYOTA SIENNA
3.3L
V6
4WD
AUTOMATIC
128,000 MILES

Thermostat housing had broken in the side the lower radiator hose goes into. It had popped out and all the coolant had drained out. Replaced the thermostat housing and filled up the coolant. Turned the vehicle on and blasted the heat. The coolant filled to the top and starting bubbling. At one time it was spilling over and then after a minute the coolant went down. Now, filled the reservoir with coolant up to the fill line. How much more coolant should I add to the system? It's not filled to the top, but I already used 2 gallons of coolant between the reservoir and the system. Is the car safe to use? The heat is on again and the temperature is in the center between hot and cold like it should be.

1 Reply

SQM

MECHANIC
6,383 POSTS

Hello,

You had the initial bubbling over due to all the air in the cooling system. As air expands much faster due to heat it will escape.

One way you can verify that the coolant is full. Is to start the engine with the reservoir cap open. As the coolant circulates through the engine the level can go down. If it does not go down, you can squeeze the radiator hose a few times to purge the system of any trapped air.
It is best to do it when the engine is cool that way the hose is not burning hot.
If the coolant level stays at a sable level fill up to the desired mark.

That should take care of this.

Let me know of any questions.
Thank you.

https://www.2carpros.com/articles/engine-coolant-59420607