I wouldn't leave the tap water in there long term. I ran tap water in the intercooler for my Radix for awhile, and after a year or so I got some nasty buildup in there.

If you're gonna flush the system out, here's what I would do (or did do, when I swapped from dex-cool to standard green stuff):

1. Remove water pump and hoses
2. Remove coolant tank and hoses
3. Remove the radiator
4. Use a hose to spray water into the lower coolant passage on the front of the block. Continue to spray until the water coming out the top passage is completely clear with no orange tint to it. Do this to each side
5. Do the same to the radiator.
6. Do the same to the hoses leading to the heater core
7. Using a wet/dry shop vac and an extension with a small round inlet, put it over the lower coolant passage on each side of the block and suck as much of the water out as you possibly can. Do this for both sides.
8. Do the same for the heater core...put the vacuum nozzle over one of the heater hoses and use it to suck as much water out as you can
9. Drain the radiator
10. Reinstall everything and refill with coolant and distilled water.

 

Tap water has a high particulate count and high minerals such as calcium and chlorides. Both will lead to build up and corrosion. Good stuff in above post

 

Word, I wouldn't touch the tap water at my parents house. They have well water and even their faucets have made calcium buildup. It's a bitch trying to wash your truck with it too because the hard water stains are terrible.

With that said, does it really matter how much coolant you use? Isn't the point of it to keep the water from freezing? Technically if you lived in an area that never freezes you could use straight distilled water correct?

I have no idea so I thought I'd ask.

 

Coolant has anti-corrosion crap in it to keep the insides of your cast iron block from rusting, or in my case aluminum from corroding and clogging up everything.

 

Do a flush this week end.
depending on where you live and what is all in it, tap water loves to
corrode aluminum.

Pick up a 2 1/2 gallon jug of distilled water and a jug of dex cool.

 

For a full flush it takes about 6 gallons of anti freez watewr mix. That is for the raidarior and block.

 

distilled water is only 64 cents a gallon from walmart so quit being a cheap ***. LOL just kidding.

 

im too lazy to do yalls flush method. ill just buy alot of distilled water and pull my thermo and crank it up and pour it in one side while it flows out the drain on the radiator