Coolant leak E350 cdi

[Xemim11]

Hi,
Today in the morning I unplugged egr cable then i start car and after 2 minutes i had “top up coolant see owners manual “ on dashboard and i went for a drive when i came back after 10 min there been loose of like 2-3 l of coolant and been smoke coming from under my bonnet , you guys think it could be something with egr ? Because i have egr off in ecu or it can be just some radiator connection? Is mercedes e350 cdi 2010 coupe
Thank you

 

[MrGreedy]

Common leaks are expansion tank cap and the top hose to the rads, but the leaks could be from anywhere in reality.

I also mention the first 2 locations because they are easy to see. Check if you can see any salt like crystallization deposits visible anywhere as these generally identify the leaking area, unless it's a more catastrophic leak, in which case you will need to look for fluid leaking out.