Coolant reservoir leak

custom_build

Hi, any help would be appreciated. It's a 2015 ford transit courier. I've noticed the coolant level dropping very slowly over time, topped it up but then the same situation again. It seems to be leaking from this circular hole. Is there supposed to be a rubber bung or something in there. Thanks in advance.

custom_build

To be clear, the small circular hole in the second picture. Which is on the underside of the reservoir.

Cetyl Palmitate

I have the same issue in my car actually. I've just been topping up every couple of days/weeks. Not sure if I should seal it or not? I'm guessing not?

Kimbot

That looks like a screw hole to keep it all sealed shut, check and see if the screw has completely come out of it and if so I would replace the screw and see how you get on.

custom_build

On second thought,I'm thinking that might be an overflow and there's probably a small leak somewhere else along the line. Might be one for the mechanic at the next service. I'll just keep topping up untill then as the engine isn't overheating or anything. Fingers crossed it's not the head gasket.

teediddlyeye

Theres no screws in an expansion tank.

That looks like a drain hole if it boils over. Has it been overheating? Could be as simple as the seal on the cap.