I wasn't referring to thermostat replacement process. I meant the process of engine coolant drain/FLUSH/fill which is described in the document that you posted. I was just wondering why it is a preferred step to take if it could be done without it.

As far as thermostat goes, it stay in there until it causes problems. I would rather follow time tested advice this time - if it is not broken, don't fix it. So far, it has been doing just fine according to the reading on the COOLANT display. No leaks, as well.

 

You do need to remove the t-stat to change the coolant because it is normally closed, you would only get the old coolant from the bottom half of the system, if that due to vapor lock.

You know the put your finger over the end of a straw in your Dixie Cola and pull it out trick. Then amuse all of your friends when you remove your finger and get the Dixie Cola all over them.

 

So that was you ? Don!! Good analogy!