Coolant: From Green to Red

I had to do a solid two day flush on my 1st gen after swapping out the water pump/timing belt. My son drives this truck now and when the water pump started leaking good, he was a few hours from home and didn't have access to the Asian red stuff, so he topped off with the generic green stuff to get it home.

Lots of distilled water ran to full head up, drained, refilled and repeated again and again until the drained distilled water was almost drinkably clear.

I had a lot of gallon jugs of antifreeze/distilled water to take to the transfer station to properly dispose of it.

This pic is just one gallon from each purge. The bigger jug of red/green mixture was the stuff he drove home with.

 

Can't you just stick a garden hose where the thermostat opening is and run it until water runs clear out the lower hose/opening. Then quick flush with a few gallons of distilled water and fill?

I'm running stock red and no plans to change because I'm lazy, but I have seen blocks flushed like this before. If I had green I wouldn't switch it back for the same reason.

 

Looks like you worked your ass off!

Did you drain the engine block after flushing or just the radiator? I’m only asking because I can’t find the damn drain plug on my 5vz-fe engine.

 

Personally I’d rather stick with green than run a hose through it. But I’m sure it would do a great job of getting the old color out lol

 

I did some research on this (for domestic vehicles) several years ago. It isn't about the brand of coolant, it's the design of the cooling system that is important.

The traditional green coolant of the last century is an Inorganic Acid Technology (IAT), it was designed to form a film over internal surfaces to isolate them from oxygen. The vehicles of the day had the radiator top tank as the highest point of the cooling system and it (the top tank) wasn't completely filled, there was an air space for expansion as the coolant heated up. Again, the film was to isolate the metal parts from oxygen. IAT coolants were recommended to be changed every 2 years usually.

As vehicles became lower in the front for better fuel efficiency the radiator could no longer be the highest point, it was now fully submerged. Routine service was more difficult on these modern vehicles, so a longer lasting coolant was desirable. Modern engines used more aluminum which the IAT coolant couldn't protect as well as it did the iron and steel of the older engines.

Organic Acid Technology (OAT) coolants were introduced, they no longer filmed the metal for protection as this wasn't needed on the vehicles it was specified for. GM DexCool is an example of an OAT, Ford and Chrysler developed Hybrid Organic Acid Technology (HOAT) coolants which seem to be a better product for longevity and protection. (opinion)

The problem with using an OAT/HOAT coolant in a old vehicle designed for IAT is the air space in the radiator tank, OAT/HOAT coolants form a corrosive fog in the air space as they are designed to be used in a fully submerged application. Additionally the coolant probably picks up some oxygen when cycling through the top tank.

I only researched domestic vehicles so I won't comment on the proper coolant for a Toyota application. I will recommend to research what the original specification called for and then find a coolant as close as possible to that specification. Manufacturer branded coolant from the dealer in 2021 my not match what was specified in 1990.

It isn't about being a good or bad product, is about being the correct product and meeting the specification that the vehicle was designed around.

 

I just used one of those funnel things that attach to a radiator cap thingy, and fill the rig up with distilled water until the funnel is half full so I could monitor the color as ot changed during a full heatup cycle.

I had the front of the truck up on ramps to facilitate a good burp each time. It also helped to slide a piece of cardboard down in front of the radiator to help it fully heat up.

 

I think a saw another one of your posts that went into great detail about coolants but some of it was over my head. However, the info you provided is one of the reasons I’m on this search to figure out what’s best for my truck.

If only I could just Google that phrase and click “order now”

 

Perhaps a lubricant of some kind, I believe this is my first post regarding coolant.

The important point is to research what was originally specified and find something close as possible.

People selling parts are generally useless at things like this by the way.

 

I recently flushed my coolant and replaced it (it's always been red, but not necessarily Toyota OEM pink). I got as much out via the radiator drain as possible, filled with distilled water, ran it, etc.. I noticed that about 1/2 of the fluid was not draining out (presumably it's in the block and other lines) so I left it overnight. In the AM, I had almost all 2.25 gallons in my catch bucket. Filled it with new premix and considered that chore complete.

 

Ya I’ve learned the hard way to not assume the guy at the parts desk knows anything about cars.

 

That’s interesting. I didn’t even think to try letting it drain overnight.

 

brother, to most sales guys the right part is the one in stock.

 

I’m glad that a place replacing my water pump and me buying Walmart Prestone for him to use, the mechanic pointed out that that wasn’t the recommended coolant to use. Other places might have just put in what I bought and been done with it. Heh, the only thing keeping the coolant draining out while on the freeway was the built up crusty deposited scale at the leak area. Bullet dodged.

 

Sounds like you got a great mechanic.

At first I was kinda irritated that my mechanic never even offered another option besides the generic Prestone All Vehicles coolant. But honestly I think they just err on the side of cheap because most people want to get their cars back on the road for as little as possible.

Another great example why it’s important to do your homework on any repairs, even if you aren’t qualified to DIY.