Official Coolant Flush Guide

[Csmithbass]

Great info

Thanks for the rad post! I am tearing down my 3.0 V6 post Hydrolocked/head gasket blow out

I just drained my coolant out of the radiator last night, via petcock, but the Haines manual I’m using has a diagram showing the engine block drains...yet I can’t seem to find them.

I am debating looking for a new radiator as I have seen specks of coppery/gold floating in the reservoir. Any thoughts?

I have been around this ‘95 4Runner for the last 6 years, and never seen red in it. I will be refilling with red or pink...what ever is recommended.

 

[Glorious Leader]

About to do my first ever rad flush ever. Of any vehicle. Learning how to this adulting thing people speak of. Super helpful write. Thanks so much

 

[Jacob_116]

Rad Flush with 50/50 Zerex Coolant

I am planning on doing a radiator flush for an upcoming road trip. None of my local dealerships have the Toyota coolant in stock and If I order it online it will not come in time (totally my fault for waiting last second). Any ways I am planning on using the Valvoline Zerex which is a red 50/50 pre diluted mixture. My questing is if I do a flush with distilled water and don't drain the block would it be potentially harmful as the mixture would no longer be 50/50. The Zerex jug says do not add water to mixture. Should I be safe?

 

[AuSeeker]

I am planning on doing a radiator flush for an upcoming road trip. None of my local dealerships have the Toyota coolant in stock and If I order it online it will not come in time (totally my fault for waiting last second). Any ways I am planning on using the Valvoline Zerex which is a red 50/50 pre diluted mixture. My questing is if I do a flush with distilled water and don't drain the block would it be potentially harmful as the mixture would no longer be 50/50. The Zerex jug says do not add water to mixture. Should I be safe?

Ideally the entire cooling system should be filled completely with the 50/50 mixture, and is how I would suggest you do it.

That being said the system will work with just plain water but will not be protected from freezing, they say the anti-freeze also helps keep things cooler but I can't imagine how.

 

[Jacob_116]

Ideally the entire cooling system should be filled completely with the 50/50 mixture, and is how I would suggest you do it.

That being said the system will work with just plain water but will not be protected from freezing, they say th anti-freeze also helps keep things cooler but I can't imagine how.

So ideally when I am finished with the distilled water flush, I would then do a coolant flush, then refill radiator with coolant and it should be 100% Zerex?

 

[AuSeeker]

So ideally when I am finished with the distilled water flush, I would then do a coolant flush, then refill radiator with coolant and it should be 100% Zerex?

It's depends on the cooling system capacity, half of that capacity should be 100% pure anti-freeze for a 50/50 mixture, so I would do the flush and drain out enough water to add the anti-freeze amount needed and then top it off with more water.

 

[phattyduck]

Ideally the entire cooling system should be filled completely with the 50/50 mixture, and is how I would suggest you do it.

That being said the system will work with just plain water but will not be protected from freezing, they say the anti-freeze also helps keep things cooler but I can't imagine how.

Water is BETTER at cooling than glycol coolant... as long as you don't need cold weather protection (I'm talking like, below 0*F) you don't need 50/50 ratio. You do have to change it slightly more often because you have less anti-corrosion additives. I generally aim for 40% or so coolant since I deal with high temps more often than low temps.

-Charlie

 

[2TH4IST]

4runner gets 50/50 all the time due to traveling to freezing climates. It also has a bottle of water wetter in it as well. You will never get 100% of the old coolant out or the distilled water. It is what it is. You will be fine with a little of distilled water with the pre mixed coolant.

Regarding straight water, yes it's better then coolant. I use it in my miata, never goes to freezing climates. 1 bottle of water wetter and distilled water, works great.

When I flushed my 4runner's cooling system it used around 7 gallons of distilled. Had 2 5 gallon jugs to use to recycle the old stuff at the city yard. I used a vacuum filler for the cooling refill. Cleaned out the 5 gallon jug. Mixed one concentrate toyota red to 1 gallon distilled. Think it took 3-4 gallons.

 

[VIPinfiniti45]

Pretty cool write-up, thanks. Only suggestion I can think of is between steps 4 and 5 before shutting down engine spray some cool hose water thru radiator for just a minute to cool things down a bit to minimize the hot water spewing out.

Or not. :cowboy:

this is a very bad idea for 2 reasons.
1. hose water contains minerals, and putting said minerals into a hot engine block will instantly crystalize the minerals and start clogging up your coolant system. This is why you only put distilled water in coolant systems, it's mineral free. The hose method is okay to do if the engine is already cooled down, but you must also be sure to flush that out as well with distilled water before getting the engine warm again.

2. Cold water and hot metal = have fun buying a new motor, because you likely just cracked your engine block doing this. In general never put hot metal into cold water, it causes the metal to contract too rapidly and will make it extremely brittle and crack. Even on the off chance you get lucky and didn't crack the block fully, you will have certainly caused micro fractures internally in the metal which is also no good.

 

[96RedRunner]

this is a very bad idea for 2 reasons.

BS What do you think happens when you are driving in the rain.

 

[Jdog98]

I don't think the rain is getting into your cooling system...