Overflowing coolant reservoir

[zulfi.tahir]

AoA
I own WagonR VXL, 2015 with 112000 km on the meter. I am using Suzuki recommended coolant for radiator.
Recently I have noticed a little coolant under the car, on investigation it was found that the coolant is overflowing from the reservoir.
Please note that the coolant level was at the recommended ( marked) level and radiator is also full.
I want to ask what can cause the coolant overflow as I have not added additional coolant.
Your responses are highly appreciated
Thanks

[engnr.mubashir]

Could be bad radiator cap as cap is necessary to hold down the coolant pressure. Change the cap.

[zulfi.tahir]

Coolant is not overflowing from radiator cap. Coolant is overflowing from reservoir (small bottle) connected to radiator

[engnr.mubashir]

Bro when there is bad radiator cap coolant ever flows to reservoir.

[Xulfiqar]

you see overflow coolant and yet level is correct in reservoir bottle and also in radiator?

[aminjafer5441]

Seems like a bad or improperly seated radiator cap as it's not holding in the coolant pressure and it's overflowing into the reservoir. Check if the reservoir cap is also properly seated and remove the radiator cap and reseat it once after cleaning the rubber seals inside with a soft cloth. Do all this when the engine is cold, preferably first thing in the morning. Lastly check if the leak is from the small hose that goes from radiator to the overflow reservoir. Sometimes this pipe hardens due to age and constant heat cycles and starts leaking from either end.