OAT or IAT?
 

Can someone point me in the right direction and tell me which of these coolants I need for my 2002 WRX?

I've read my owners manual and the only piece of information I can find is this;

"For adding, use genuine SUBARU coolant or equivalent: A mixture of 50% soft water and 50% ethylene-glycol" - Which I've read that OAT and IAT both contain.

Most of the information on the net doesn't state which coolant I need exactly OAT or IAT (unless I'm clearly looking in the wrong places :lol1: )

So long as you don't mix the two, you can top up with any decent antifreeze, diluted to 50%.
DO ask the vendor if it's suitable for an alloy engine and has corrosion inhibitors...most are, and do.

If doing a complete change, I'd use the IAT on that model.

odd, i have just posted something about coolant in the KTM forum...
In the Soarer I use Millers Alpine coolant (which is OAT) with Redlines Water Wetter
Millers Alpine
Water-Wetter
I have also used this set-up in my past three Impreza (Classics) without any issues.
I do know someone who has started using the Evans Waterless coolant in his Blogeye and has noticed a temp difference.
I know that the Japs always say to use OAT coolant in the engines.
But as Alcazar says dont mix the two, flush out the system totally with a dedicated coolant flush or vinegar (really!)