As BigIslandSevens said you're gonna want to check out the radiator as well.

I don't understand why anyone would even want to risk running non distilled water in your cooling system. At $0.99 a gallon it's more then affordable, especially for an RX7 owner.

 

waterpump lube? im not sure what that is... i probably have seen it but please elaborate .

(ive had to fill my radiator up a few times with the horrible water that comes out of my tap... i filtered it with my PUR tap filter, but thats all. i couldnt get ahold of any distilled water last coolant change. anyway, now im worried..... so, how do i clean out those deposits without taking apart the motor??? thanks, heath

 

I'm going to chime back in and attempt to answer/clarify some key points:

The rust inhibitor/waterpump lube that is commonly available is nothing more than water soluble oil repackaged for automotive use. It turns a milky white when mixed with water. It is commonly used for corrosion protection in heavy equipment, large diesels, industrial engines, boilers, etc., when there is no requirement for freeze protection. It is also the same stuff that is used as a coolant and lubricant for flood cooling on lathes, mills and other machining operations. I do not know if it is [chemically] compatible with alcohol based anti-freeze, but I find the observation made in a previous post by mr rx-7 tt about no corrosion to be significant.

I would not expect ordinary treated tap water to be significantly more corrosive than processed water, it just contains more TDS (total dissolved solids). Whatever you do, just DON'T use soft water, particularly from a home water softener. The real affect of regular tap water may be to reduce the effectiveness of the A/F solution somewhat requiring a stronger concentration of A/F. And tap water, particularly in areas of the country such as Southern California that have very hard water (>13grains/gal) could lead to [calcium] deposits in the cooling system--unsightly, but not corrosive.

As for deionized (aka "soft") water vs. distilled:

Distilled is just that and should have very little or no dissolved solids, i.e., minerals, to crud up the system.

Deionized water, on the other hand, is intended not to react with soap and precipitate stearates and palmitates (soap scum). This is achieved by removing the Calcium and Magnesium ions and can be done in a number of different ways. Problem is, the processes are not perfect and can result in small quantities of salt (CaCl2) that remain in the water. This is especially true of the common zeolite (ion exchange) process. THIS WILL MAKE THE WATER EXTREEMLY ACTIVE AND CORROSIVE. Aluminum is a very active metal and is especially vunerable to the cathodic process. In the presence of an electrolyte and a dissimilar metal it will form a battery, disslove the aluminum and deposit some of it (as in electroplate) somewhere else in the cooling system. This process is greatly speeded by application of heat, which is why the exhaust port area may be more affected.

If you really wanted to get fancy about this, one could measure the conductance of the water to determine which will have the least galvanic effect. (Water with < 1000 umho/cm conductance should be OK.)

In simplified terms:

Distilled = low TDS & minerals = less deposits and crud

Low conductance = less ions & low salinity = less electrolysis

If you are going to try DEIONIZED water, taste it first. If it has a salty taste DO NOT USE IT in your cooling system.

So did this help anyone or just create more questions?

 

I have only used distilled water in all of my cars over the years that had aluminum engines. First Alfa Romeos, and for the last 21 years RX-7s. Never had any cooling system or seal failures.

Also forget about the old green crap, go new orange non-silicates like DEXCOOL.

Invented in Europe where they have more aluminum engines, and longer experience with them.

 

Glad i went with a 80/20(distilled)+watter wetter mix

 

Also forget about the old green crap, go new orange non-silicates like DEXCOOL.

I agree that you should use silicate free but,
Just because it is green does not mean that it has silicates in it. Most new quality coolants are silicate free due to the overwhelming use of aluminum in or engine. ( USA built cars and etc..) The color is just that a color. read the instructions and ingrediants before use.

In fact as an example. HONDA uses a silicate free pre-mixed coolant for their motorcycle shops to use. The coolant is green and silicate free.

 

This post is to correct an error I noticed in my last post above, which has bugged me all night long. I incorrectly referred to SALT as calcium chloride (CaCL2). What I meant to refer to is the common salt sodium choride (NaCl), which is often found in excess in so-called deionized or soft water. And not to mention, in our food! Mmmm...

FWIW: According to my brother who used to work for GM, Dexcool was developed to help with the Aluminum situation and that it is supposedly less corrosive [than green], although I don't know exactly why.

 

i've read bad things about dexcool in very high temp engines...



go Evans!

 

Care to elaborate?

 

problem is if you flush the engine with tap water you can never get it all out....and I always flush the engine as opposed to just pulling the drain plug

 

I was some time ago, I don't have any links but basically engines overheated when the dexcool lost it's properties and became a dark sludge...


edit: found a link: http://www.wcpo.com/wcpo/localshows/.../20299ce7.html

make sure to check out the links at the bottom of that page, some nasty pics of the dexcool coolant

 

dexcool is also a plasticiser, softens plastics. it is seen as the cause in a ton of class action lawsuits in gm and the manifold leaks. honda has tried to pull out of it's contract with gm to build the ion engins i belive because they use dexcool.

 

For effective corrosion protection, most antifreeze types require 50% mix at a minimum. I think this was more of an issue than florida tap water, assuming it was not softened water.

I use low silicate Zerex G05, a hybrid that has benefits of dexcool w/o the bad baggage. Ok with tap water, but I've used distilled. Among other problems, dexcool tends to leak. Happened with my fd and another car ... leaks stopped when I went to G05.

 

I use good ol Prestone (the green stuff)....water pump looked great when I pulled it off (bad seal)

 

Dexcool (or go5) contains organic acids, that's the reason it softens plastics and must be used on vehicles specifically designed for dexcool as it will eat through certain metals.

 

Ive had tap water from various parts of the USA , Europe and Asia. Water was different in its mineral / particulate matter level. Florida water was very "hard, alkaline, felt different and tasted different. You could look at various signs of mineral buildup around plumbing parts.

Point being that different regions will produce varying degrees of mineral deposition with different types of chemical compounds. Some probably clean out just fine with tap water and have no adverse effects.

HERES AN IDEA - ANY THOUGHTS ON THIS? For example: We clean mineralized coffee makers with vinegar and water. Is this something that may work for our cooling systems when we flush it?

ELECTROLYSIS - Heres another thought about healthy cooling systems. When I installed my new ron davis all aluminum radiator, there were many warnings about checking for electrolysis, checking for ac and dc voltage in coolant to ground and maintaining good grounding and the use of non aluminum fittings.

CHUCK