Loss of radiator water and strange sound from exhaust

[saadahmad.shaikh]

I have got honda city exi 2000. The radiator reduces water and need to be filled about half a liter after every two days. There is also thermostat installed in the car. The car never gets overheated and there is no visible leakage from hose pipes or radiator.

The water in the radiator does not have bubbles, there is no oil in radiator and the engine oil is also fine with no whitish milky stuff.
I am really confused what is the reason for significant loss of water so frequently.

P.S: there is some strange colorless smoke or weird sound from the exhaust

[creamheart_777]

simply check the radiator cap, if the cap's rubber seals become hard then the car can behave like this.

[s15]

Open radiator cap when engine is cold.
Let the engine get warm till mid point.
Then check bubbles at high rpms.

If thermostat valve is closed, it traps air bubbles too, since the small hole in valve for bubbles usually gets plugged with rust. So bubbles are only visible when thermostat valve is open.

First check bubbles this way and post back findings.

Steamy fumes from exhaust is usually bad head gasket if it's also creating bubbles in radiator which is dependent on engine RPM.

Any milkiness in oil cap?

[humayun.chughtai.7]

Do check for any water leakage under the passenger side floor mat, may be ur heater coil is leaking. Same happened with my vitz a week ago. I was very curious about water reduction without any other leakage or head gaskit signs.

[saadahmad.shaikh]

i am currently using the 0.9 bar pressure radiator cap..is it the right one or should i change it to 1.1 bar pressure cap?