Flush anti freeze from engine coolant

[Chris]

We have a 3GM30F Yanmar which is 8 years old. about 135 hours on the engine. I read that the engine coolant needs to be replaced every 3-4 years. I have not done this and have never done this on an engine. I was going to use an oil suction to take out the old coolant and replace with the right mixture. Anything else I need to know?

 

[Rick I]

There's a coolant drain

on the right side of the engine towards the rear(if I recall right). How can you have an 8 year old engine with only 135 hours on it?