[Drnick]

Question; 2022 ZL1, what is this lower reservoir
Which is below the reservoir that u normally fill with
Antifreeze ( dex cool) ? It has a small flip cap which
Says “Dex-Cool”??

[NYTMARE23]

Not 100% sure what it's for either, but I DO know the top one should be completely full and the lower one at the half mark on the tank.

[RobZL1]

Top one is pressure expansion and lower is the reservoir. The two communicate through a small channel that is molded into the plastic. It's the same as if the bottom tank was somewhere else and there was a line coming off the top tank right under the pressure cap.

When the top tank coolant expands, it lifts the spring in the cap, and then liquid flows down the molded channel into the lower tank. When it contracts, it pulls liquid from the bottom tank into the top tank.

You initially fill the top tank when it's drained or extremely low on coolant. Then once the top tank remains full, you fill the bottom tank to the mark. As long as the system doesn't have a major leak or use any coolant, you should only need to fill the bottom tank through the small filler neck for normal upkeep.

[bishopts]

Originally Posted by RobZL1

Top one is pressure expansion and lower is the reservoir. The two communicate through a small channel that is molded into the plastic. It's the same as if the bottom tank was somewhere else and there was a line coming off the top tank right under the pressure cap.

When the top tank coolant expands, it lifts the spring in the cap, and then liquid flows down the molded channel into the lower tank. When it contracts, it pulls liquid from the bottom tank into the top tank.

You initially fill the top tank when it's drained or extremely low on coolant. Then once the top tank remains full, you fill the bottom tank to the mark. As long as the system doesn't have a major leak or use any coolant, you should only need to fill the bottom tank through the small filler neck for normal upkeep.

I fill the lower tank from the upper tank, in the thread area of the cap you can see the hole. Just fill it slowly to the top of the threads and it will drain down into the lower tank. It's handy if you don't have a small funnel to fill the flip cap filler hole.

[Gunkk]

Originally Posted by Drnick

Question; 2022 ZL1, what is this lower reservoir
Which is below the reservoir that u normally fill with
Antifreeze ( dex cool) ? It has a small flip cap which
Says “Dex-Cool”??

https://www.camaro6.com/forums/showp...32&postcount=2

[beowulf556]

Originally Posted by bishopts

I fill the lower tank from the upper tank, in the thread area of the cap you can see the hole. Just fill it slowly to the top of the threads and it will drain down into the lower tank. It's handy if you don't have a small funnel to fill the flip cap filler hole.

Good trick, never noticed that hole.