Coolant not flowing back to radiator, but top and bottom radiator hoses are collapsed

Hi, everyone. I hope you are doing well.
I have a 2003 Mitsubishi Galant ES 2.4L.
I recently changed the radiator and radiator cap because there was a radiator leak and the car was overheating. The car also has a head gasket leak so I added in some Bar’s Head Gasket Fix into the radiator and coolant reservoir.
The overheating issue is gone, but now coolant in the reservoir won’t flow back into the radiator. What baffles me the most is that there is not blockage in the coolant reservoir line; new radiator and radiator cap; and that there is vacuum in both top an bottom radiator because they are collapsed.
When I open the radiator cap, the hoses will return to their normal shape.
This is the craziest thing I have ever seen.
Please help, all inputs are appreciate.
Thank you very much!

Do you notice this when the car has been used for a while, then after you park it for a while and the engine cools off a bit then you check the hoses and find them collapsed? If so either the hoses are old and too flexible & just need to be replaced, or whatever part is supposed to be allowing air and coolant back into the system as the engine cools isn’t opening. Replacing the radiator cap, plastic overflow bottle, and the hoses between the overflow bottle and the radiator is where I’d start w/this problem. If the new radiator came w/its own cap, start with just putting the old cap back on, see if that helps.

Note that the head gasket problem may not be entirely solved, and exhaust gasses are over-pressurizing the cooling system, which could cause this symptom too I think. Take a look into the radiator (eye protection) as the engine heats up at idle. If you see a lot of bubbles coming up through the coolant, that’s consistent w/a remaining head gasket problem.

Yup, I checked on the hoses after driving a while and allowing the car to completely cool down. That is when I saw them collapsed.
I have never thought about the hoses being too flexible, they look like they are in pretty good shape. Not rot whatsoever.
I have tried both old and new radiator cap, neither one worked.
There isn’t much bubble when the car is idling, but it does spill over from the top of the radiator when I rev it.
Thanks for the help.

See if you have a buildup of the Bar’s leak in the tube in the filler neck that the hose that goes to the recovery tank fits over.

Is the water circulating at all?
Could the water pump impeller have come dislodged from its shaft? It happens.
I also wonder if a chunk of the Bars Leak may have gotten lodged near an impeller fin helping it dislodge.
If you don’t see the water circulating, keep this in the back of your mind.

First, check that back-flow valve in your new cap is operating properly.
Is it even an OEM cap or some aftermarket?
It would be the first thing to check before you go replacing other parts.

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