Raidator water level very low and overflow reservoir full

[akashkhan2008]

Hey Guys!!
I have recently observed that at the end of every work day my car’s(indus corolla 1.6gli 4a engine) radiator drops water level about 250ml while the overflow bottle gets filled up to the brink which was half filled in the morning. Water is not coming out of the bottle into the rad after cool down. What could probably cause that?
Thanks in advance for the suggestions

[mshoaib432722]

Change radiator cap with a brand new one. And then tell if this thing happens again.

[akashkhan2008]

Will do Insha Allah

[humayun.chughtai.7]

Replace radiator cap at first priority.
Look for any leaks, seems like air is entering the cooling system from somewhere.
What is the condition of radiator ? Is it rusty inside ? Is the thermostat valve at its place ? Fan auto or direct ?

[akashkhan2008]

Well on inspection of the cap I found two cracks in a seal maybe thats the trouble. The rad hasbeen washed but not that thoroughly as I took it to a roadside mech for cleaning. Might still have some rust inside. Couldn’t get the thermostat checked so can’t say and I put the fan to direct as a precaution.

[humayun.chughtai.7]

If the temperature needle stays at HALF mark even with direct radiator fan, then for sure T-stat valve is there.
And if the needle remains below half near the COLD mark, then you have no T-stat valve.

[humayun.chughtai.7]

Keeping the radiator fan direct is a bad thing for your engine as well as the fuel average.
I will recommend you to get it back to default settings.
And in these engines, the temperature sensor works on fail-save mechanism i.e. if the sensor got bad, it will make the radiator fan to run all the time i.e. direct !

[akashkhan2008]

True!!

[akashkhan2008]

So here is another trouble with the radiator that happened just today. The car is heating up abnormally while the fan is direct and no thermostat as detected with the help of posts above. This morning I am topping up water in the radiator and it sinks down without apparant leak as there was no water on the floor below. I top it off again and it again disappeared after 3km drive and I had to refill again. What had gone wrong this time??? 🤷‍♂️ Help please 🤦🏻‍♂️

PS: I had an episode of burst radiator tank a month back due to failure of rad fan on highway. Could it have caused head gasket failure and water being consumed off??

[Xulfiqar]

Water/coolant comes into rad from bottle after cooldown sounds very normal to me.

Whats the issue?

Are you removing a hot cap?

[akashkhan2008]

Sir the water from coolant reservoir isn’t coming back to rad after cool down. The bottle remained full and the rad dry. Just after I posted I let the car cool off and filled radiator again and drove back probably 1km and it looked like in the picture attached

[akashkhan2008]

And no I didn’t remove hot cap. Its just when I check back after a little drive the water seems to have either evaporated or consumed or God knows what. I can see vapours coming out when cap is removed.

[akashkhan2008]

Seems there was a typo in my original post. Sorry for that🤦🏻‍♂️

[Xulfiqar]

Remove overflow tube along with cap, check to see if it has a hole anywhere where it can suck air.

If there is a hole in it, system wont suck back liquid as air is easier to suck.

Similarly if any such leak exists anywhere else, like in rad cap, radiator tank seam, headgasket, hose pipes etc. You will get these symptoms

[akashkhan2008]

Will do Insh a Allah