My coolant needs a tiny bit topping up after a recent repair, and I used up all my green Prestone. Yeah I know it's only like $20 at the store but I have an almost full jug of almost new Mercedes Blue Coolant (bought for my other vehicles). Can I just put that Mercedes Blue Coolant in my 04 G35's reservoir to get it up to the "min" mark or it will create some kind of adverse chemical reaction? Winters get very cold here so I'm afraid to just add distilled water.

 

Ymmv, but if the chemical compounds aren’t compatible it could cause sludge. Check the chemical makeup of each. Blue could just be a color dye for all we know.

 

Personally I wouldn't, you can buy a bottle of Nissan compliant Asian dark green coolant pre-mixed for under $20. Just make sure you aren't getting the new blue Nissan coolant, your 2004 uses the older style dark green coolant.

 

Thanks for your thoughts guys. I decided not to mix different coolants either (funny thing I had dexcool and this Mercedes coolant on hand but no traditional green coolant haha) and instead put in like half a quart of distilled water and that should be good for now. I'll do a freezing point check one of these days when I find my gauge to make sure it won't freeze up to minus 40, should be fine. Yeah I'm cheap, it's not so much about the $20 just buying 5 quart coolant just to put in less than half a quart and have the rest sit on the shelf for like 5 years opened getting old anyway.

 

Yeah just distilled would be fine, also it's not traditional green coolant, it's the Asian specific DARK GREEN coolant that was used in the late 90's to early 2000's. Toyota was the oddball, they used their own special pink coolant that looks eerily like dex cool.

Before it freezes next winter suck out the radiator with a coolant % tester just to verify it is good enough for the lowest temperature in your area. Don't exceed 60/40 unless it's a racecar (most tracks make you run pure distilled anyways just for cleanup after wrecks) and don't go higher than whatever like 10 degrees lower than the record lowest temp is in your area for the last few decades. Somewhere between 50/50 and 60/40 coolant to water is usually best.

Prestone AF-1420 is super cheap (like less than $5) and accurate, I've seen contractors at work using the exact same one on multi-million dollar hydronics units lol.