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Engine coolant replacement questions

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New User

Nov 22, 2022, 8:24 AM

Post #1 of 3 (444 views)
post icon Engine coolant replacement questions Sign In

When I had my mechanic replace the engine coolant on my 2015 Nissan Rogue a couple of years ago, he used Valvoline Zerex G-05. I just noticed that Valvoline says that this is not the right coolant for my vehicle and I should be using Valvoline
Zerex Asian Vehicle Blue Silicate and Borate Free Antifreeze / Coolant 50/50 instead. Since the two coolant types might not be compatible, I had to flush out all the old coolant. That's a tedious process because only about half of the 2.25 gallon coolant capacity comes out with each drain of the radiator. I did 6 iterations, with the coolant coming out clearer each time. Each iteration requires draining all coolant from the radiator petcock, siphoning out the coolant reservoir, adding distilled water to the radiator, and running the car for 30 minutes till the thermostat valve opens.

My question are:
1. What would a professional do if a customer wants the coolant flushed and replaced? It's hard for me to imagine they'd spend the 6 hours to do what I did, but how else would they be sure to get all the old coolant out unless they open up the engine and remove the thermostat valve?
2. How is a person supposed to get the right coolant concentration when adding 50/50 coolant after a distilled water flush? When the 2 gallon system starts out filled with distilled water, adding a gallon of 50/50 gives you only a 25% concentration in the system. If you let that mix then drain the radiator and add another gallon of 50/50, then you only have a 37% concentration. What I need is concentrate, not 50/50, but Valvoline doesn't seem to make a concentrated version of Zerex Asian Vehicle Blue. Unsure

Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Nov 22, 2022, 8:41 AM

Post #2 of 3 (442 views)
Re: Engine coolant replacement questions Sign In

We have a few ways to do this.

Some shops have a machine that pushes the water or coolant through the system.

Another way is to remove the lower hose and the thermostat and run the hose through the thermostat housing until it runs clear and then drains. You can push the remainder of water out with air pressure from the top.


We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.

New User

Nov 22, 2022, 10:20 AM

Post #3 of 3 (427 views)
Re: Engine coolant replacement questions Sign In

I see. Thanks! Smile

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