I'm seeing a few different part#s so which one is right/current for the correct coolant for a 2004?

 

Don't look at part numbers, look at the bottle. So long as it's the Honda TYpe 2.. you're good

 

I was always told to just be careful not to mix coolants of different colour. The rest is not important. If i am wrong please explain to me.

 

The color of the coolant has nothing to do with said coolant's composition; EVERYTHING else IS important. The questions you need to ask regarding a replacement coolant is, "Does the coolant contain an ethylene glycol base or propylene glycol base; does it contain traditional corrosion inhibitors, organic acid technology (OAT), or hybrid organic acid technology (HOAT)?

For Hondas (and Toyotas) they use an ethylene glycol base with a specially formulated OAT which is similar to GM's DEX-COOL, but removes the 2-EHA component and relies exclusively on sebacate for corrosion protection. For Honda's, either use the OEM coolant (regardless of color) or Zerex Asian Vehicle Antifreeze (once again, regardless of color); I've compared the chemical makeup of the coolant to Honda's specs and they are virtually identical.

 

Since the OP asked for the part number, this is the Honda Part # OL999-9011. However as stated above if it says Honda Type 2 you are fine. It think the Acura variation of it says Acura Type 2 & should be Part # OL999-9011A.