Coolant Question

[TimeFlies]

Since the average car/suv/pickup engine has the same metals in it, and the cooling system components are also all similar, why so many coolants?

Should it not be fine to use distilled water, and drain and refill the cooling system of a vehicle say 5 times, to get rid of most of the current coolant in it.
Then use another coolant without consequences?
If not, why not?

I was asked today why not just use any coolant, and couldn't really answer the womans question, as to why not.
I honestly don't know why?
Mazda, Honda, Jaguar, Mercedes, Ford, Jeep, Ram, Chevrolet, Audi, Nissa, Porsche, Kia, Fiat, Genesis, and all the other companies, say their vehicles require a specific coolant be used.

Why?

My F150 V8 has Peak brand coolant in it, and has for years.
I drained and refilled it with distilled water, over and over again, then used Peak, not Ford.
I've been told over and over not to use the wrong coolant, but never heard a good reason for it.

 

[Kira]

Some coolants do not mix well. I've heard they can gel.
Certain coolants, Dex-Cool, for example, are designed for air-tight applications only.
We had a Jeep in the family which had a simple flap on the reservoir which was free to breath as the coolant expanded and contracted.
Dex-Cool in that application would gunk up and clog radiators and heater cores as it's exposed to air all the time.

Should it not be fine to use distilled water, and drain and refill the cooling system of a vehicle say 5 times, to get rid of most of the current coolant in it.
Then use another coolant with consequences?

It should. The instructions always say: Rinse 'til clear.

 

[thastinger]

I have REALLY lived this over the past couple of years as our fleet has aged and we have rolled vehicles into the rotation to support kids coming of driving age.
Have been down the gold/orange/yellow/convert orange to yellow/Asian blue in two of them although the 2.3L Mazda is fully a Ford engine.
Next time they are all due I think I'll just put the John Deere Cool Guard in them and call it a day.

 

[Urshurak776]

I had a GMC Sierra I got from my Dad that had the original DEXCOOL stuff filled at factory. Had 125K on it, roughly.

I drained everything I could, then flushed with distilled water several times. Replaced water pump and thermostat. Put new belt on. Drain and fill with DI water again. Drained and filled full concentrate Peak Global Lifetime. Still close to 50% water in the engine once drained. So added full concentrate and 50/50 to the overfill resevoir.

Got rid of the truck at 325K. Between 125K and 325K i Did 2 drain and fills of 50/50 Peak Global lifetime.

Truck ran like a champ.

 

[SHOZ]

I upgraded my fleet from green generic to yellow long life generic.

 

[bdcardinal]

I have REALLY lived this over the past couple of years as our fleet has aged and we have rolled vehicles into the rotation to support kids coming of driving age.
Have been down the gold/orange/yellow/convert orange to yellow/Asian blue in two of them although the 2.3L Mazda is fully a Ford engine.
Next time they are all due I think I'll just put the John Deere Cool Guard in them and call it a day.

So what's fun is when the same coolant used by 2 different manufactures have different supercessions. Ford used the FL-22 that Mazda uses for a short period of time. Mazda still uses the FL-22 while applications that called for Motorcraft Dark Green coolant now take the Motorcraft Yellow.

 

[TimeFlies]

If I flushed a 2010 Tacoma cooling system with distilled water 5 times, then added Peak All Vehicles, that should be fine I assume.
I did it to my own vehicle, but don't want to ruin the neighbors.