Sumith, I have theory. The gurgle was the system air-bleeding itself.

This happens often after changing the thermostat, and causes it to run hot. So now let it cool down, top up the radiator with more coolant, and it should be good.

12.8psi according to the manual.

I'm not sure I will check.

Hi Levey

Good Point Actualy I am not having Original Radiator Cap, this is from some other vehicle, i can't remember what model was it ?
What is the PSI rate for Datsun 1200 standard is it 15 or 17 ?

thanks
regards
sumith

Maybe your radiator cap has a too high pressure rating and is not releasing the excess pressure?

Hi Levey

I don't have reserve tank in mine,it sound like Air in the cooling system (that is a common problem as i have searched from other forums) the solution is to re flush you cooling system and refill it again..do you think the gauge indication in yellow (in the above pic) is too hot ?
have you any one ever experiences driving for this much of higher engine temp ?

Thanks
regards
sumith

As for the gurgle sound: do you have a coolant return resevoir? that can make that sound and is normal.

Maybe buy another new thermostat and see how that goes, also check the sender resistance just to be sure.
Or try pulling the centre out of an old thermostat, refitting it and see how it goes, works for me but my engine is modified.

I don't know. Maybe someone else can comment.

Hi DD

and i am worried about
What is the Gurgle sound coming from car bonnet also ?

Thanks
Regards
sumith