Aoa All,
My car XLi 2007 was performing well, when I drive it locally and on the highways and now it has started to give the noise. It got it checked by the local mechanic and I found the reasons of belt and bearing. He checked my car and suggested change of belt and bearing. But I felt I bi change.

BEFORE:
When my car was running, on opening the radiator cap o r radiator plastic bottle cap then water does not come out so there was no danger of burning of the engine.
It listened to someone if your car got too hot, then you should not switch off the ignition and let the engine of your car running and open the radiator cap, If the engine is started, let the water flow through its engine to make it cool after some time and I followed this piece of advice.
NOW:
When the engine was hot and I let the engine of the running and during this time, I opened the radiator cap to check water level. Suddenly the water from radiator smashed with great speed and I hardly managed to save me from this hot water and from being hurt.
I have already checked the water in the engine two o r three times and it is usual, if the radiator is hot, whether engine is switched on o r not, water comes upwards and there may be the chances of burning o r hurting.

QUESTION:
Q1. Is something wrong o r it is ok to water to come out, when engine is switched on?
Q2. What is the sign of a malfunctioning water body? My car does not decrease water o r does not face the issue of heating.
Q3. What I should do now to prevent water coming o r smashing out?