If I were to go to a shop that has a coolant flush machine and I decided to use the Nissan blue long life 50-50 coolant:

1. How many gallons of 50-50 coolant should I bring for a complete flush?

2. Would you recommend also bringing distilled water to first flush out the old coolant with water and then flushing the water out with fresh coolant? If so, how many gallons of distilled water? If this does not make any sense, my apologies in advance, I am far from a gearhead.

 

Your cooling system holds around 10.5 quarts, or a little more than 2-1/2 gallons total. IIRC, for the blue long-life coolant, they sell gallons of premix 50/50 and quarts of 100% concentrate. Pricing is not always proportionate between concentrate and premix, so you'll have to decide which works out best. You could bring 3 full gallons of premix, or 5 quarts of concentrate, or 2 gallons of premix and 1 quart of concentrate, etc

If you drive in a fairly temperate area without extremes in temps (hi or lo), and you use only distilled water to mix your concentrate with, I wouldn't bother worrying about having only 5 quarts of concentrate to mix for a 10.5 quart yield. Instead of 50/50 concentration, you'd end up at about 48/52 % which should be fine.

As far as the distilled water goes, I definitely recommend it, but I'm puzzled why the shop doesn't have or offer it if they have their own flushing machine; just seems a bit odd. Regardless, do not let them flush it with regular water, there's just no reason to introduce any impurities. Distilled water is very cheap. You can pick it up for as little as 79 cents a gallon, so there's really no reason to sweat it over a bunch of extra gallons here or there.

 

Thank you for the answers. I will go with 3 gallons of distilled water followed by 3 gallons of Nissan 50-50 blue coolant. I thought that was right based on capacity.

The shop I use has coolant and transmission flush machines but lets you bring your own fluids and just charges for labor. Bringing the above and 16-quarts of Matic S for a couple of flushes. Thanks again.