So I was low on coolant/antifreeze. I thought it’s not a big issue, so I went to O'Reilly Auto Parts to get one. I told them the year and the make of the car (2005 G35 Sedan). They told me I should get Zerex 675130 Asian Vehicle Anitfreeze/Coolant (http://amzn.to/1W1HZhR). It said for Infiniti on the back, so I bought it and went home and added some into the reservoir. I don’t remember what the color in the reservoir was prior adding Zerex; I thought it doesn’t matter since they all have the same purpose. However, I noticed my car consumes a lot of coolant. I usually add a little bit each month. Is this normal? I also noticed my engine heats up and the fans turn on when I drive a lot or fast. Is this normal? I have this car for 7 months now, and that’s the time it took me to finish a gallon of Zerex coolant. I bought it used and I don’t know what the previous owner used and whether he had similar problems or not. Anyway, since my Zerex gallon is finished now, I have been was looking for other options in the market; maybe something better. However, I discovered people saying I should only use the Nissan coolant (http://ebay.to/1Il6yyU); the GREEN one. I even called an Infiniti dealership asking what kind of coolant I should use. They told me Nissan GREEN. Keep in mind that Zerex is PINK. I thought that’s not an issue. I’ll get the Nissan coolant and mix it with distilled water (50 – 50, since I live in CA) and add it to the low PINK, Zerex coolant. Then, I read online that I should never mix 2 different colors, because it’ll lead to engine problems. I am confused and worried now. What should I do? I don’t want to do a flush; I cannot afford $150 - $250 at the moment. Help would be appreciated! Thanks!

 

It's always good to stick with a factory coolant in my opinion because I don't like the preservatives they use in the aftermarket anti-freezes. I am not familiar with Zerex specifically but I imagine it's similar to peak and such. With that said, you did not damage the engine by mixing the coolants or using an aftermarket coolant.

If you are consuming/losing coolant, that is a clear indication of a problem whether it's as simple as a leak or a compromise in the combustion chamber/cooling system. The first step is to pressure the cooling system with one cooling system pressure test kits out there with the appropriate radiator neck adapter.

 

It's more about the additives that cause the problem. I think since that Zerex was designed for Asian vehicles you should be okay. I think you want to stay away from anything with silicates if I remember correctly. I just buy OEM fluid off the Internet to make it easier.

You could have a leak at one of the hoses, head gasket problem, leaky water pump seals, bad radiator cap, or leaking radiator.

I'd inspect the two hoses on the radiator, the one on the reservoir tank, heater core hoses, and there is another on the sides and behind the engine.

Maybe replace the radiator cap also.

If you spend about 30 bucks go to AutoZone and rent their block tester. You fill it with fluid and syphon in air and if the fluid changes color it means you have the more expensive fix of a bad head gasket. How does the car run?
You can rent a pressure tester for about 200 bucks from AdvanceAuto like Mac says. That will tell you if there are any leaks and show you where the fluid leaks from.

I had a leaky radiator on my 06 Coupe that I replaced almost two years ago.

 

Thanks for the replies, guys! I was skeptical about mixing them together. I even talked to Valvoline rep. few days ago, and he assured me there will be no problem mixing them together. Anyway, I went to Nissan dealership and bought the green coolant, which is $27.07. I added it on top of my pink, Zerex coolant after mixing it with distilled water (50-50). So far, no issues!