Best practice for changing coolant type.

When my truck came to me, it had green coolant.

When my radiator failed in the middle of winter, I just replaced the coolant with more green because I was working in a couple feet of snow and didn't want to mess around.

However, I am aware this is not the proper coolant for our trucks.

What I am wondering, is changing coolant type as simple as a draining all the green I can get out and replacing with red? Or is there is a flush sequence? If a little green mixes with red does anything bad happen?

 

I've seen a few here comment on flushing it out with water (hopefully distilled) and then and only then replacing it with red. I think the idea is the red and green can chemically interact in a bad way.

 

As a follow up....what is the worse sin....sticking with pure green, or possibly mixing red and green?

 

What did you do?!

 

Like I said, its had green in it since who knows when.....

Just wondering if its worth the hassle or possible risk to go to proper red at this point.

 

I was just teasin, I think what jack said, would be fine, flush with distilled, maybe a few times. Pretty sure the hand man and @Tundra2 did multiple distilled flushes( a drain on each side of the block and the rad)

 

Mixing of coolants is the worst. You should have seen the gummed up horse shit that was in crackies pipes.

I don't know if they mixed red/green or otherwise but it was FUCKED.

I did several distilled water flushes. Each time letting the whole system burp while running on distilled until I had gotten enough gunk out that I was satisfied. I probably did 20-30 flushes hat way. I was also dealing with contamination too.

The silver truck (3.4L V6) I only did maybe 10 flushes on it until I put the red.

 

Luckily, from what I've seen, the coolant system is super clean and not gunked....just the wrong type.

 

My 95 Tacoma I used to have had green coolant. My shitbox 96 camry has it as well. Never had issues with it. Not sure how much difference it really makes. Mixing them would be far worse than sticking with what you have.

 

I'd want to stick with what the manufacturer recommends, since engine blocks are different, and color of coolant is indicative of different chemical compositions, i.e. some additives or contents being inappropriate for iron or alloy blocks due to promoting rust or corrosion and thus sediment or buildup that can clog passages. I know you already know this, so I dunno why I'm saying it, but I'm not going to backspace and delete it now I've typed it.

If it were me, I'd probably want to get back to OEM. Since you're going to be flushing anyway if you chose to, I'd get some bottles of Prestone radiator flush & cleaner, and run one through with each flush after. I'd think 2-3 flushes should suffice, and it'll help break up anything in there that's fucked (if any) from the green. And frankly, I know everyone says to use distilled, but if your'e doing it for the sake of flushing things out and won't be keeping the water in for any length of time, if you're on city water, I'd feel 100% confident in using what's coming out of the water hose for the job.

 

+1 on this. Some folks recommend going the extra step to pull engine block drains, and I get it, but just like distilled vs. city water, I'm not taking the extra step.

 

When I've flushed cooling systems I do the following:

I drain the radiator, drain the block, and use compressed air to blow as much coolant as I can out of the cabin heater circuit. I capture all that coolant and recycle it. I figure this removes 90-95% of the coolant -- but I'm just guessing at those numbers.
My next steps will be considered controversial by some because I don't capture the remaining coolant -- I just let it run onto the ground/driveway because there is so little of it left in the system.
With the block drains still open, I take my garden hose and shoot water into the top of the block and let it run until the draining water runs clean. If I'm not replacing the radiator, then I do the same with that: shoot water into the top until what comes out at the bottom is clean, then turn it over and flush it the other way.
I have one of these brass nozzles which fits perfectly on the heater hoses. Disconnect both heater hoses and stick the nozzle in one of the heater hoses and tighten the clamp. Then turn the water on and let it run until what comes out of the other heater hose runs clean. Put the nozzle in the other heater hose and flush it that way. Remove the water nozzle, and follow up using compressed air to blow out the heater hoses (both ways), the block, and the radiator. Close the block drains, re-install the radiator, re-connect the heater hoses and refill the system with fresh coolant.

 

How hard was it for you to open up the block drain fittings? I tried to open one of mine in the 2nd year of ownership (brand new) and it snapped 1/2 the fitting right off the block and this was in the morning before it was even driven.

I'm guessing I may have had a defective fitting since others here seem to be able to get theirs open.

 

Both sides opened and closed without incident. Same with my 2002 4Runner with the V6 about 5-6 years ago. A piece of vinyl tubing fits the nipple on the valves so they drain into the catch container without any splashing or mess.