coolant identity
 

Not sure what coolant is in my 04 boxster S since I did not buy it new. Miles are low, but recently had a leak and lost about 3 quarts and need to top it up. I understand about not mixing the different kinds, but I can't be certain if what is already in there is oem or not. It is the green color, but that isn't definitive. I would like to just top it up and not totally flush and refill. Any way to tell what is in there?

You could always top it up with distilled water until you are ready to do more maintenance on the cooling system. Did you fix the leak?

There is no realistic way to test it to see what type it is. Best bet is to top up with distilled water or dump the entire system and put in new coolant.

+1 Distilled water is the way to go!

The most important issue is why you lost so much coolant. Do not let the car overheat, even for a moment, it could be the death of your motor.

Leak was straightforward and fixed and it did not overheat. I have added distilled water to top it up since I have no way to know absolutely what was in there. I will just go ahead and get the necessary porsche coolant and drive it as is while I decide if I want to go ahead and do a water pump and thermostat and belt at the same time. I have the situation stabilized for now and can take my time with the next step. I am leaning toward replacing pump, belt and thermostat and maybe the motor mount as well. I am not inclined toward unnecessary maintenance, but I want everything as it should be. 38K miles is a little early to be changing pump and belt, but it is also 8 years old and time can also take a toll. thanks for the input.

Smart move. Go by years, not miles. A new OEM pump, OEM thermostat, OEM belt, and 2 gallons of OEM coolant is about $300. Cheap insurance.