Hi There, My 1998 Toyota Camry two weeks ago when I replaced the front struts, the Garage said the distributor's gasket near the water pump and thermostat it needs to replace because of leaking coolant and they did. After one or two days later the bubbling sound came up and the radiator's overflow box always increasing after the driven but the temperature gage state as normal in the middle (not over heating).
I was thinking maybe there is air trapped in the engine block so I just pump out the coolant back to radiator when it cold. One week later the radiator cap has deteriorated because of the heat and now I have replaced one from old radiator (I replaced it one year ago) and the coolant is regulating (when it cool down the coolant will flow back to radiator). Now I'm afraid the cap will destroyed again (or water pump) after few days or so. The Garage said it should goes way if I change the cap or the top return pipe. Is there any reason the temperature gage gets the fake reading? Help!

Have you taken the car back to the garage that did the work and have them double check their work?
It isn't normal for any garage/shop to do the work they recommended and then not drive the car to verify the repair that they recommended actually did repair the fault plus to also make certain there are no other related issues.
If you feel comfortable taking it back, do so. If not, get another opinion from another shop. You will likely have to pay for the additional diagnosis but then you have another professional opinion. That will guide you to the next step.
If you don't know where to go, use the shop finder link in my signature to find a shop. Tell them why you're there and let them do their thing.
Let us know what happens.