overflow reservoir

[rush91]

I just changed out my transmission fluid ( Amsoil Syncromesh ) and coolant and thermostat ( Jerrys Gaskets )......but had a question on the overflow reservoir. How much coolant overflows into it? Before I changed it out, there was always some in the reservoir. But I noticed after a few days, that there is barely any in there.....Is this normal?

[A26B]

You probably lost some coolant when you changed out the t-stat. When the engine goes through a heat cycle, it will pull coolant from the reservoir during cool-down until the system is full.
Add coolant to about half-full in the reservoir. The level will stabilize when the system is full.

[rush91]

Thanks Jerry....I'll add some tonight.

[Dynomite]

Thanks Jerry....I'll add some tonight.

Like Jerry suggests.......but when the engine is Hot I fill the Coolant Overflow reservoir to within an inch of the top. On a Hot Engine the coolant overflow is filled by the expanding hot coolant to its maximum fill. As the engine cools the coolant is then sucked back into the engine.

What happens after doing some coolant draining during Plenum Pull or thermostat installations, is the engine develops Air Pockets in the coolant system. As the engine warms up to Hot these Air Pockets are flushed out of the engine into the Coolant Overflow. Once the Air gets into the Coolant Overflow the air is caught at the top of the coolant never to return to the engine (Which is exactly the purpose of the Coolant Overflow).

All the Air caught within the engine is flushed out by the Water Pump as you rev the engine once the engine has reached optimum temperature. The Air ends up within the Top Side of the Radiator where that Air is pushed out of the radiator into the top of the Black Coolant Reservoir in front of the Passenger Side Windshield. From their the air is forced into the Coolant Overflow as the Hot Air and Hot Coolant expands during engine Warm Up to Engine Hot.

If after several cycles of Engine Operation the Coolant Overflow continues to loose Coolant, You Have a Coolant Leak in your System.