The manual only says- Check
I heard aluminum blocks don't need coolant change as often due to less crrosives in system. Does anyone really know when to change the stuff?

 

I think I recall that under normal conditions the first coolant change isnt really necessary until about 60000 miles.

 

60k / 48 months allthough some people have had the need to do it sooner... http://forums.maxima.org/showthread....change+coolant

 

Yep, I would check it earlier than 48mos/60k for sure. When doing a replacement, don't go by the color. Prestone and Zerex are green but they contain both phosphates and silicates. The Japanese coolants, whether red (Toyota) or green (Nissan, Isuzu, etc) all contain high amounts of phosphates but no silicates. The extended life coolants (Dexcool, Prestone extended life) are based on OAT that has no silicates or phosphates but you have to clean the system completely and make sure it's not exposed to air or you'll get brown sediments. I would just buy the Nissan coolant for a few extra $ and be done with it.

 

Brown sediment in the coolant itself? Or in the system if it's exposed to air? Curious because I want to use an extended coolant in my Max.

 

I did research on the contents of various antifreezes. I went with Peak Extended Life Antifreeze. I used a 50% mixture of water to antifreeze plus 8 ounces of Red Line Water Wetter. This particular antifreeze contains no silicates, no phosphates, no borates and no nitrates. It is ethylon glycol based. It was only $7.50 a gallon and there was a $2.00 rebate per gallon. I was initially going to go with Nissan antifreeze but the dealer wanted $16.50 plus tax per gallon. That really bugged me on principle and that is when I started doing research.

 

What is Red Line Water Wetter and what is the purpose? I have never heard of it. Is it a coolant system conditioner?

 

Water Wetter improves the efficiency of your coolant to cool your engine! Think of it as increasing the amount of heat your cooling system will be able to eliminate!