[UnknownJinX]

Originally Posted by Wuiquen

What I am afraid of is overfilling the system. Like i said, there has been times or at least one time when I check that the level at the top and lower tanks were proper at full atthe top and half at the bottom

I would be ok filling the too if the lower tank was at the fill line or less but right now it is more than fill line so if I add more coolant to the top tank, wouldnt I be overfilling the system?

There is usually some kind of relief for the cooling system if it's overfilled.

As long as it's not as stupid as RX-8 where the coolant overflow relief dumps right onto the electric power steering connector, you are fine.

[Gunkk]

Originally Posted by Wuiquen

What I am afraid of is overfilling the system. Like i said, there has been times or at least one time when I check that the level at the top and lower tanks were proper at full atthe top and half at the bottom

I would be ok filling the too if the lower tank was at the fill line or less but right now it is more than fill line so if I add more coolant to the top tank, wouldnt I be overfilling the system?

Coolant expands a bit when hot, and the main loop (top tank) will be pressurized when hot (think: old-school radiator). So it's possible that air in the top tank can be compressed a bit when hot. It's also possible for air bubbles to circulate around the system.

This is why you check and fill when cold. There's a half-moon circular cutout in the bottom tank (visible in that manual page I show above). Fill to half-way when cold, but anywhere in that circle should be fine, IMO.

If you're way over-filled (i.e. bottom tank completely full), then expect a bit of coolant to come out when the car heats up. The only harm it will do is make a bit of a mess when it overflows a bit when hot.

[Wuiquen]

Originally Posted by Gunkk

Coolant expands a bit when hot, and the main loop (top tank) will be pressurized when hot (think: old-school radiator). So it's possible that air in the top tank can be compressed a bit when hot. It's also possible for air bubbles to circulate around the system.



This is why you check and fill when cold. There's a half-moon circular cutout in the bottom tank (visible in that manual page I show above). Fill to half-way when cold, but anywhere in that circle should be fine, IMO.



If you're way over-filled (i.e. bottom tank completely full), then expect a bit of coolant to come out when the car heats up. The only harm it will do is make a bit of a mess when it overflows a bit when hot.

Which radiator upper hose does the manual refers? The small hoses or the big one going from the thermostat housing into the rad?


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[Wuiquen]

??

[Gunkk]

The point is to top it up when cold.

[LT4Greg]

Originally Posted by Wuiquen

??

Fill the top reservoir to the top and the lower reservoir or tank halfway like the manual shows when cold. It’s not rocket science. Good luck.👍

[Wuiquen]

Originally Posted by Gunkk

The point is to top it up when cold.

I get that. But the manual (post #2) shows in step 4 to top it all off at the top tank and half at the bottom. Then let the car run with the top tank cap off and fill port cap off until the upper radiator hose starts to get home. Turn the car off. Put the cap back on the top tank and close the fill port for the lower tank and let the car cool down. Then inspect again to check the level. So my question was which hose are they referring there?

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[Wuiquen]

Originally Posted by LT4Greg

Fill the top reservoir to the top and the lower reservoir or tank halfway like the manual shows when cold. It’s not rocket science. Good luck.

I was referring to step 4 on the manual posted on post #2.

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[LT4Greg]

The upper radiator hose going into the thermostat housing is the one the manual is referring to. Hope this helps you.

[Wuiquen]

Originally Posted by LT4Greg

The upper radiator hose going into the thermostat housing is the one the manual is referring to. Hope this helps you.

Yes it does. Thank you. So quick question, I ran the car for about 5 mins and that hose never got hot at all. Should I let it run for longer?

The small house coming from the top tank into the radiator and the thermostat housing got hot

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[Camaro1973]

Originally Posted by Wuiquen

Yes it does. Thank you. So quick question, I ran the car for about 5 mins and that hose never got hot at all. Should I let it run for longer?

The small house coming from the top tank into the radiator and the thermostat housing got hot

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Its not going to get hot until the car reaches operating temp and the tstat opens to let coolant through. Drive the car.

[AZIROC]

When I bought my '18 zm1 (non-1le) it had 32xx miles on it. I didn't know about the coolant level thing and prob a week after I drove it home I learned about it and it was the same as yours OP, about half way on top. didn't notice any performance issues on the 14xx mile drive from TX to AZ though. Bought some coolant at the dealership and topped it off. Put about 100 miles on it in a few small trips and it went down a hair. Topped it off again and its been full for the last 1300ish miles.

[ZED SLED]

My top tank is full and bottom tank is pretty much empty. I know the bottom should be about half full so does anyone have any experience with this condition? Plan is to get a gallon of Dexcool 50/50 and fill the bottom chamber thru the service port per the manual. Just wondering if I might have something else going on. Also, while I'm at it, I plan to burp the IC lines as that's never been done that I recall.

[Rock-It Man]

There's some bad advice in this thread that contradicts the OM instructions.

The upper tank is part of the pressurized system. Topping it off is essentially like topping off the radiator. The only way to do that without trapping air is to do it while coolant is being circulated. That's why the OM tells you to run the engine and top off once the thermostat is open. Only then you can adjust the lower tank level.