Is it possible to overfill a car radiator when topping up?

I assume the answer is yes? Not needed to top it up in over two years, but yesterday noticed it was rather low, just under the 'MIN' mark on the reservoir. Today after a drive of 40 or so miles, water could be seen trickling out at the bottom underneath the radiator.

What do the STW experts reckon?

Cheers all!

I should think it's coming out the same hole that resulted in the low level in the first place!

I repeat. It's not been topped up in OVER 2 years. Surely some of the water in the system just 'goes down' over time?

maybe its only just started leaking…

Sorry, I read OP as it's been level for 2 years then suddenly needed filling. I'd have thought that if you brimmed the header tank leaving no air for expansion you could have forced a joint somewhere in the system (hopefully somewhere easy to get a spanner into)

Hopefully the rad cap would have popped before blowing a hose off anywhere. Did you top the radiator up or an expansion tank? A rad should be brimmed, and expansion tank only to the MAX line.

If you have coolant trickling out from underneath, this should be you main cause for concern.

Right just been underneath the car (Peugeot 106 1.1 btw, as basic as they come) and the left hand side of the radiator is loosing water, pure, clean, cold water. So the question is, would this be release of the possible excess water in the radiator?