Is there such a drain plug for this W203 V6 engine?
(for the coolant change)

I couldn't find it given the space around both sides of the engine are
really tight. Even if there was one, I don't think I can reach it.

Thanks

It's there. Red in color usually. Drivers side. You'll have to remove the front plastic belly pan.

Is it below or above the exhaust pipes on the driver side?

You really ought to have the service manual for your car.

Coolant replacement is a quite complicated process requiring battery disconnection and an expensive special tool.

I've done plenty coolant changes, but after reading the M112 procedure had the dealer do it.

[QUOTE=lkchris;1829291]Coolant replacement is a quite complicated process requiring battery disconnection and an expensive special tool.QUOTE]

Special tool for what? Battery disconnect why? I changed my coolant, no problem, nothing special.

I'm not sure what you are talking about but I have done plenty of 112 and 113 coolant changes. No battery disconnection is required and no special tools. You just have to make sure you bleed the air out.