What if any adverse effects does running tap water vs distilled water in the cooling system cause? And what is the best antifreeze to use? My questions are for my '85 22re.

Mineral deposit buildup will result form using tap water... This will cause clogs and corrosion in your cooling system, resulting in premature failure of the radiator as well as electrolysis in the head's cooling passages blowing the head gasket.

Use any quality green coolant with distilled water for best results.

what is the best cleaner to use to flush out the block? I have been using tap water in my rad and I am sure the PO did the same.

Actually, it's been argued for a long time that using distilled water is really worse than tap water. The argument goes something along the lines of distilled water being heavily ionized, which leads to it being 'hungry' for electrons, which it conveninetly strips from the inisde of the block.

Etylene-Glycol coolant is chock full of corrosion inhibitors, and the only time the type of water you use will actually hurt you is if, like most vehicle owners, you leave the same coolant in the vehicle for 10 years. It's only good for a year. If you pop your radiator cap and it's not neon-glowing mountain dew, change it.

FYI, this is one of the reasons it's HORRIBLE to run straight water in a cooling system. One, water rusts the inside of the water pump and block, two if there's a freeze, you need a new block, and theres a couple of others. Just don't do it. Add some antifreeze, dammit.

You can get a zerex brand cooling system flush at most autoparts stores that works pretty well. Or, just change the coolant 3 or 4 times in a year. I've found that works pretty well on a brown & scummy cooling system as long as it's not HORRIBLE.

Ordinary green antifreeze is just fine, and it's what the 22R was designed for.

I like Toyota red, it's formulated a little differently. But green will do. I also will only use distilled water; lime deposits from the hard water around here are evil.

IMHO Avoid that GM dexcool red stuff like the plague! It is crap, Ive heard that from a few sources and mechanics.

Trust green stuff, and change as per the manufacturers spec.

I would only use distilled water in an OPERATING cooling system. Flushing with tap water may not be that bad. Distilled Water is a solvent and therefore dissolves a suitable solute no different than tap water. The only difference in the tap water is that it potentially has a solute already dissolved into it, in which you are introducing into your various coolant passages.

Agreed, avoid GM Dexcool. Toyota red ain't too expensive and it's made for the application.

along the same lines, how do you guys dispose of your old coolant?

parts stores here have oil recylcing, but I've not seen any for transmission fluid or coolant in over 10 years.

Actually , pure water is not heavily ionized, the correct description would be a very stable molecule.

Distilled water doesn't have the minerals (disolved salts including usually alot of calcium)but when it does then you have alot of ions disolved which are what cause the precipitous deposits you get in you cooling system. These same salts are responsible for helping transmit current and another form of creating deposits and that is electrolysis. Pure water doesn't conduct electricity.

To clean your cooling system, buy a couple of gallons of the cheapest vinegar you can find , drain the fluid and replace with the vinegar. Run the engine for 1/2 hour letting it come up to temp so the thermo is open and also keep the heater on so the core gets washed . The acetic acid in the vinegar will dislodge and dissolve most mineral deposits. Shut off engine , let cool till warm , drain , and flush , drain then flush with 1 Tablespoon baking soda/ gallon water , let sit for 1/2 hour then drain once more and flush till your hearts content.

Replace with your favorite coolant (i like toy-red) and distilled water only

Baking soda ,,, not baking powder!

I know about fifteen Toyota Techs that will dispute you on that statement. They are designed for Toyota Red Coolant.