anyone can help with a leak on my berlingo

[addo]

The heater is not the simplest job on a Berlingo. It requires either an amateur with a spare weekend and good skills/tools, or a pair of mechanic/apprentice half a day. This realistically takes in removal of the dash, a wipe down of the mess, replacement of the heater core, reassembly, a coolant flush, fill and bleed. After thirteen-odd years most cars are a bit chatty behind the scenes so you often need to re-foam vent gaskets and stuff like that if you're thorough.

The carpet is fitted before all of the dash on a Berlingo, to remove it and valet after it's been made filthy with coolant and general dirt, is a major hassle - careful slitting with a knife will help.

[Gadgetman]

Oh man... DO NOT BUY!

I don't know which engine model it is, but leaky cooling and overheating is bad... really bad...

On a 1.4, and possibly some others, you need to jack up the front lefthand corner before filling, as you won't be able to properly bleed the air from the system.
On gasoline engines, you risk burning the top if the cooling isn't working properly. That means new plugs and headgasket, and possibly renovating the top itself. That's expensive.
(A long term 'slight overheat' is worse than a 'sudden boil' a couple of times)

I've swapped the engine in my Mk. I 1.4i, but touch the heating matrix?
In your dreams!
And if there's an AC system, ouch!