Coolant Flush/Replacement/Conversion

radensb

I know, I know - there are many coolant threads and I have been looking through them. I just got done cracking open the timing cover to replace cam phasers and gallery gaskets. I also replaced everything else in there, including the water pump for good measure.

About 5 years ago, I bought new radiator hoses, drain and bleeder o-rings, and Nissan blue 50/50 premix coolant from the dealer. It sat on a shelf until the leak Nissan said was imminent started, but it never did. Fast forward to now and my recent work gave me the perfect opportunity to use those items.

I have an '09 with the green coolant. I got the blue because the dealer said it was compatible and had it in stock at the time. I read on this forum that mixing blue and green means that you have to go by the green coolant life, which seemed like a loss. Also, my green coolant was probably starting to get corrosive as it was VERY old, so I decided to just flush it all out. I used DI water and over the course of 4 flushes, the water was coming out pretty clear (very little green tint).

Once flushed, I filled the car up with the Blue Nissan coolant. I poured both gallons of the 50/50 premix in a 5 gallon bucket and filled the system using a vacuum fill tool. I then put on a burp funnel with more Blue coolant and let the engine run for 15-20 min with occasional revving to remove any additional bubbles. The front of the car was on ramps, which I think helped get the last bit of air out. I also used the vacuum tool and burping method to flush with the DI water. I was surprised to see that the car only took in ~1.25Gal of the Blue coolant as there must have been more water than I thought in they system after I drain from the radiator. Assuming a quart in the overflow container, thats ~ a gallon of 50/50 in the system with the rest DI water, or a 75/25 water to coolant ratio overall.......

Questions:
* Is this ratio actually a concern if I don't live in extreme weather?
My concern is more diluting the detergent and lubrication chemicals in the coolant more than anything. This is my DD and doesn't see heavy use (no tracking and only 78K original miles).

* Should coolant that has been sitting for 5+ years be avoided, even if it was unopened?
I read mixed things about this.

*Should I just drain my 75/25 mix and pop out the block drain plugs to fully empty the system?
I thought that just draining through the radiator was enough, but it clearly leaves more water in than I thought.

Bottom line, I just want to do what is right for the car. I'm not too concerned about buying some new coolant and doing a block drain if that is what is recommended. I read through this very informative post, which does mention the block plugs, but diluted that knowledge with videos that showed the more simple radiator drain and refill. My (faulty) assumption was that a little DI water would be left and a slight dilution wouldn't be a problem, but 75/25 is way more than I thought it would be.

Thanks for the wisdom!

ZoomZ

I believe after 2006 or so, Nissan switched from the Green concentrate to the Blue 50/50 in all their vehicles.

Green was good but needed mixing and probably not in line with modern ingredients.

The 50/50 is very good and painless to use. All weather and seems to last longer. (I bleieve any 50/50 is good for -35c)

I would never mix the two for the reaons i suggest. It's ok, but I think you reduce the Blue's effectivity. Not a scientist or have the product ingredients, so it's just my belief.

I have used old (5 years) coolant, never noticed an issue. Noting failed prematurely. It is alcohol, so if sealed, should not evaporate too much. Thewn again, anything is possible.

There are devices you can buy that measure dilution levels, but I think that will just tell your mix ratios and what temprature they are good for. On the other hand, if your mix fails to meet the numbers, it may suggest your Coolant is failing or other problems

Ph can also be measured with Litmus paper. You'll have to research proper PH levels..

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radensb

Thanks for the info! Ill look into testing the coolant to see whats up. If it really starts bothering me, Ill just do a proper block level drain and refill....later 😁

Averying

If you’re concerned about excess water in the system reducing the amount of overall coolant and thus increasing the freeze point, just do one more normal drain/fill and you’re golden.

If freeze point isn’t a concern, just lubrication, throw a bottle of water wetter in. It’s pretty normal for folks to run distilled water + water wetter and it’s totally fine. Water wetter requires more frequent replacement though, so I recommend just doing another drain/fill with 50/50 blue like I mentioned above.

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