Golden80

I see a lot of people use distilled water in their radiators. Do many of you do the same? I've always used tap water and have never had any problems.

aboatguy

I don't know about "BAD" I guess it would depend on your tap water. If you live somewhere with lots of stuff in the water (Iron, calcium, or at a PH extreme) using tap water would be bad. Using distilled water ensures that you are not putting water that contains stuff that will clog, rust, oxidize, etc your engine's cooling system.

Corvette Kid

And it's very cheap so why not?

c4cruiser

The service manual specifies the use of distilled water and most all shops will either have distilled water available or will use a bulk pre-mixed coolant that is antifreeze and distilled water.

Most any grocery store has distilled water and it usually runs about $1.00 per gallon. A complete cooling system flush in a C4 is about 4 gallons so a 50-50 mix of antifreeze and water is only 2 gallons of distilled water. For $2.00 it's a good deal to do.

92ZR1WANNABE

Yes distilled water is better for your system then tap.

Not only because of the lack of minerals in the water , but between the distilled water and good alum. safe antifreeze it kills any chance for electrolysis.

If you have alot of "hardness" in the cooling system with alum. parts the spinning rotor of the water pump will cause a static like charge that will eat chunks out of the alum water pump housing.


I have a old water pump it took out of my 97 dakota that was destroyed because of this. Ill post some pics for ya. It literally took chunks out of the housing and finally started to leak.

Ram Air Formula

127k miles adding 400+ a week. nothind but dexcool and tap water. no problems from using either. well except for the stupid fact that they put plastic side tanks on radiators now.

stevec4

For a single change of fluids you are not gonna hurt anything by using tap water but bearing in mind these cars are up to 20 years old and if the fluids have been changed say twice a year then that's 40 changes with tap water and that's gonna start hurting things if the water is hard (calcium deposits) so if you can use distilled water then do so but don't worry if you can't get hold of it for this change.

HOOBS

I am a plumber by trade and even normal tap water I would not drink anymore...purified water is the way to go literally. I have been living on reverse osmosis water the last 3 years and when I drink normal tap water I get an upset stomach....besides when you actually see what water does to (copper) pipes you would understand! And yes I have heard it depends on where you live...but it actually doesn't...remember when there is a water main break or a new home being tied into the system there is always contamination...That's why now a days ph testing is "hourly"...If you don't believe me try this....Buy a fresh bloom of flowers and put them in a purified water vase...I gaurantee you they will last 1-2 weeks longer than normal tap water....Ever see a tumbler humidifier? the calcuim white look and crusted crustations? That's from normal tap water....I don't mean to preach but I don't at all drink tap water.

CentralCoaster

Mine didn't seem like a problem either, until water started getting into the oil.

Tap water = High TDS (dissolved solids) = Better electrolyte = more corrosion. This is especially a problem if the coolant % isn't enough, or if the car sits for awhile.

The purpose of antifreeze, is to increase the pH which inhibits corrosion, and of course, to lower the freezing point.

Here's what electrolysis looks like between a cast iron head and aluminum intake:

CentralCoaster

Especially when it's hot water. And the car is running way hotter than any 130* copper lines. The water out here by the ocean is terrible. I guess we're the last ones in line.

cv67

I agree distilled water is best. If you have time, take a sample of tap water into your local pool store and have the PH , alkalinity and hardness checked. Ususally the hardness coming out of most taps should be 80-100 ppm, which is very good. 350, 400+is a little high. If the ph is low (corrosive) or to high, they will tell you-Another way to base your decision if you have the time. I've been working at homes that had a perfect ph coming out of the tap, drove to another 2 blocks away and found the supply corrosive. Its a crapshoot, for sure.

BTW, this should be done for info only. Don't add pool products to your radiator water

MtlSphere

Anybody ever watch "MythBusters"?

I saw this recently and it was definitely a "Oh wow"!

They heated tap water and distilled water in a microwave. The tap water boiled, the distilled water didn't. They explained that it's the impurities in the water that cause the roiling action when water boils. Distilled water can be "superheated" without the same roiling action. As part of the experiment they hung a sugarcube or something over the distilled water then superheated it. It didn't boil but when they dropped the sugar into the water it was like an explosion!

So, does that mean that distilled water has a higher boiling point too?

Nathan Plemons

I have to believe that it all dlepends on the quality of your water. Around here we have pretty good water, pretty much everybody runs plain tap water and there are no problems at all. Sure distilled water is probably better, but I'm usually not planning my cooling maintanence that far in advance.

No certain places, like Crossville TN for example have water that is so hard it would probably destroy a car in no time.

aboatguy

It goes back to it's cheap and does not hurt so why not use distilled water!!!

I think it's funny that people who spend big money on synthetic oil, additives and other such stuff will balk at spending an extra 2 bucks for distilled water every year or two.

CentralCoaster

You beat me to it.

You guys rave about Mobil 1 this, Mobil 1 that, synthetic polymers and detergents and changing a 15,000 mile oil every 2500 miles "only the best for MY baby"

Yet you don't want to spend $2.50 at the corner store to put the right kind of water in your car.

TheStef

Being from Canada... we measure temperatures in Celsius. Here's what I know for fact.

0 Degree's Celsius is the freezing point of water and 100 Degree's Celsius is the boiling point, and when mixed with anti freeze is brings up the boiling point and brings down the freezing point.
Most cars coolant "from what I've seen" will be around 85 to 95 degree's Celsius. I seriously doubt the boiling point has anything to do with the corrosion of the block or heads.

Distilled water for human consumption is not very good, it strips the minerals from your own body. I used normal water on my last coolant change, but after reading this post and realizing that I winter store my car 6 months out of a year, I should really use distilled water.

VAHROOM

Is it OK to flush with tap water?

Don't mean to steal the thread. Just curious.

CentralCoaster

Read above, it's the high pH in the glycol that helps prevent corrosion. I use hosewater to flush of course, just drain it out afterwards.

The big question we should be asking is, whether deionized water will give us more protection than distilled water.

rws.1

distillation and deionization are two routes to the same place.
The prior boils the water which leaves the minerals behind and then condenses the purifed water for use.
The later uses an ion exchange column. As the mineral laden water passes through the packed column, it runs over the surface of millions of tiny beads. The beads have a coating that binds the calcium and magnesium leaving the water free of the minerals as it passes by.

newbecorvetteguy

My unscientific opinion based on my years of experience is it's ok to use tap water. Been using tap water for my 33 years of driving. We used well water in everything on the farm I grew up on. Tap water was used in the two dealerships and one truck shop I worked at. Never ever had or heard of anyone having a problem attributed to using tap water. Would distilled water be better? Probably a technical sense. Is tap water good enough? imo, yes. Especially if you change it every couple years (the green stuff anyway) like you're supposed to. If I were going the dexcool route and planned on leaving the stuff in for 10 years at a time I might consider it.