I popped open the hood today and noticed the coolant resevoir was pretty low, this was the second or third time I had to refill it. Anyway, I remember I only had a little bit left of the Prestone coolant, so I went to AutoZone to pick up another. I bought the one that you can use right away, it's already diluted for you. So I bought it back home and was about to pour in the remaining coolant from the other one and noticed the two were different! OMG...the one I have been using was the original non-diluted one that you have to dilute yourself! I refilled the coolant resevoir with the new already diluted coolant. However, in the system now is about 1/4 diluted coolant and 3/4 non-diluted coolant. I originally had the already diluted coolant in there. When I removed the SC, I had to drain/refill the coolant. I refilled the coolant with about 1/4 left of the diluted coolant that I had at the time. I needed more, so I went to AutoZone to pick up another. Without really looking, I picked up the non-diluted one. Of course, I didn't know at the time. Only today did I know. A bit too late now. Any harm in this? Should I drain/refill the whole system again?


I can't believe how careless I was.

 

 

Just drain out a little, and then fill with straight water. I don't see why you would have to drain it all out? Just make sure you get one of those antifreeze testers and make sure it tests O.K.

 

You should definitely drain and refill the system properly. Pure "coolant" does not provide nearly enough heat capacity. You've probably been ok so far because it's winter, but come summer, you may have problems. Also pure coolant is not good for all the various seals and such in the system.

 

Yeah I think I might just go ahead and drain/refill the whole system. School starts next week, so better do it now or I won't have time to do anything when school starts. I was planning to do an oil change this weekend. So might as well do both.

 

Make sure you use distilled water too.

 

Definitely drain and refill it. Coolant alone does not really have the heat transfer capacity of water. Nissan recommends a 50/50 mix optimally, but can go as high as 70% coolant / 30% water.