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How to properly mix coolant and water

64K views 32 replies 14 participants last post by  netnews  
#1 · (Edited)
Which of these statements is true or false:

1. Using 100% anti-freeze/coolant in your engine radiator will NOT decrease the cooling ability of your cooling system.
2. Using regular tap water, especially water that is considered hard is perfectly fine to mix with engine coolant, and will not over time cause any deposits to form in the cooling system.
3. Distilled and deionized water are not at all the same and neither should be used in an engine cooling system, use regular tap water.
4. Straight water in a cooling system will actually cool better than a 50/50 or 100% antifreeze mixture.

OK, questions 1, 2, and three are totally FALSE, question 4 is a trick question, it is TRUE but, it is not good to use only water in your cars cooling system.

Here are some interesting factoids:

If you drain your cooling system completely and refill it with 100% antifreeze, it will actually run hotter than it would with a 50/50 mix or straight water. I recently proved this by picking up the wrong jug (not a 50/50 mix) and filling my system with almost pure coolant. The net result was the engine ran a LOT hotter than it did prior to the service. When I drained out 50% of the cooling system capacity and refilled with water, the system then ran cool as it should. I made no other changes.

Concentrated antifreeze in a cooling system should never be used without adding water. At least 40% of the mixture should be water. If antifreeze is mixed with distilled water at the ratio of one part antifreeze to one part water, the freeze protection will be down to –34°F and boil- up to 265°F that is if using 15 PSI pressure cap.

The question comes up: Do I use regular tap water when mixing my coolant and water together? No, you should use distilled water or better yet, de-ionized water. The reason for this is that tap water has minerals that can form deposits inside the radiator and the cooling system passages of your engine. And over a long period of time they can lead to over-heating.

For best all-around protection, use a 50:50 mixture of antifreeze and distilled or deionized water. Coolant should not be mixed with hard tap water. Hard tap water has excessive calcium and magnesium deposits that can cause scaling, which will result in inadequate heat transfer. Use only soft or de-ionized water that is not treated with salts or chlorides. (OEMs publish limits in parts per million (ppm) for hardness, chlorides, sulfates and total dissolved solids for the water used to dilute antifreeze.)

For most applications, distilled and deionized water are the same thing. Both are just water with ions removed. Distilled water has been deionised by distillation as apposed to another technique such as ion exchange chromotography. The end product is the same and either can be used. Most labs will not have distilled water anyway even if some people still call it distilled rather than deionised.

You can buy distilled water at the pharmacy CHEAP! At CVS it is $.99 a gallon. The most I have seen it sell for is $1.98 Amazon sells distilled water for $19/gallon...it's a total rip-off. Go to the pharmacy or Walmart. Look for distilled water that has NOT been flavor enhanced. Flavor enhanced means they put back in salts and other minerals to make it taste 'better'. Desani water, a coca cola product, has more than a dozen additives for example to 'help the flavor.'

The safest and best solution is to purchase a 50/50 mix of coolant and water, premix. All coolant manufacturers use distilled/deionized water to reduce the coolant concentration. Else, you can save a few bucks, buy distilled water at the CVS pharmacy and mix it 50/50 or better yet 40/60 (water/coolant).
 
#6 ·
FWIW, you can by distilled water at any grocery store, or Walmart as mentioned. I don't think I've ever paid more than $1.50 a gallon for any no matter where I bought it.

For cooling if not living in an are where it freezes, a 70/30 water/antifreeze mix seems to work best. You need the antifreeze in the system for lubrication of the water pump.
 
#10 ·
i think 70/30 gives maximum freeze protection, lowest freezing point

This hotrod article states water is the best conductor of heat, adding antifreeze reduces the ability to remove heat

Glycol Or Water - Which Is The Better Coolant? - Hot Rod Magazine

Bottom line: A large-tube aluminum radiator filled with pure water and using at least a 20-psi cap is by far the best heat-transfer setup, provided the vehicle is not subject to freezing conditions. Be sure to add a corrosion inhibitor when running pure water.

I just run a 50/50 mix because its easy, for best cooling performance it would be 40%AF to cover -12F (sufficient for my area)
 
#12 ·
Here is a copy of a post the Pope made some time ago. I really like first hand experience posts by knowledgeable T-Ders over cut and paste articles. Sometimes the accepted norm doesn't apply to all engines, kind of like PCV systems on our 8 V engines.

Thanks
Randy

86 GLH S60
86 GLHS 373
89 Turbo Minivan
83 Rampage Turbo


Quote:
Originally Posted by tekman View Post
To start with, make sure you don't have TOO MUCH antifreeze. Old school days of pouring a gallon on antifreeze in and topping off rest of system with water no longer work with these small volume systems. Antifreeze is a corrosion inhibitor, and freeze protection chemical. It's heat transfer properties suck. Too much, and it will cause overheating. Unfortunately, since these 2.5's are famous for head gasket and head cracking problems, I suspect that is really the source of your overheating. Take it to a decent radiator shop; they can check antifreeze concentration, and also put a Carbon Monoxide sniffer on your radiator and tell you if the problem is your head. Good luck
.



This statement is right out of the book, and doesn't work very well with TDs. Unless your running low boost and basically stock the 50/50 trip doesn't work out. BTW 100% antifreeze is really closer to 80%, my cars find this. I run 100% and drive hard like normal and the car boils the 20% into the catch tank. Then I keep adding 100% until the car stops shooting / boiling over. Once the car gets to a true 100% and doesn't have any air pockets the car doesn't get hot anymore. I run my GLHS at 115 MPH for 550 mile stretches through Nevada's back highways going to Vegas. The car holds 115 MPH and 7 PSI for hours at a time with the AC on.

The big difference between TDs and most of the world the "book" refers to is the boiling point of glycol vs water. Fact is that even if it can't transfer heat as well as water, glycol still transfers heat better than a large steam pocket in the head or turbo. Our chambers boil water on the surface and the turbo gets to 1,400 degrees. My car would always run hot with the lean running MP stage 2 computer.

This winter the cars with 100% were fine in the morning and my 90 TBI car wasn't. By having 50 / 50 the coolant froze and the car over heater trying to melt the system. 100% doesn't freeze, turns into a slime. Between the cold, the boiling over and the over heating I can't tell people to run 50 / 50. Sure you may run a bit cooler, but that is only before you boil. Then once the system boils over your done. Everyone should go have there rads flushed once in a while, were not talking big money here.
__________________
Rob Walsh
 
#13 ·
If you are boiling over with a 50/50 mix, then you might have other issues. I had an issue with my truck boiling the coolant and tracked it down to a bad radiator cap that wouldn't hold pressure. When the system isn't under pressure it boils at much lower temp.

Also, if you are freezing a 50/50 mix, then you must hit extreme negative temperatures where you are, or you don't have a true 50/50 mix. Use the coolant testers to make sure you are covered for the temps you will experience in the winter. Only time I have EVER had my coolant freeze was in my truck running a 70/30 mix in negative temps. And even then it didn't freeze solid, just kind of became a slush. 10 minutes in a heated shop and is was liquid again.
 
#14 ·
FWIW, I have close to 60/40 water/antifreeze mis in my car right now. Cruising at 80 mph with A/C on, boost or not, it will hit the high mark in "normal" range but not go any higher. Without A/C on, it runs at the low mark of normal range. Using a 180 t-stat.
 
#15 ·
I'd like to know what makes our engine so different?

Few things I know about antifreeze ... without adding water it freezes around 0-5 below (f).
Without added water, heat transfer is down by 30-40%
Adding water helps suspend the additives put into the antifreeze to protect internal parts.

For the best of both worlds, run a summer mix in the summer.
 
#19 ·
""Sometimes the accepted norm doesn't apply to all engines, kind of like PCV systems on our 8 V engines.""


What I was referring to is, in my opinion, removing the PCV system on our engines is a safety measure. Most engines will sludge up without one but all my 2.2/2.5 Turbos do not, even during the coldest winter months. So I always ditch the PCV to keep my engines from injesting any octane reducing crank case vapors in the air intake system.

This ties in with the Popes post about running straight antifreeze so I'm thinking there might be some merit to his theory. While straight A/F will have your engine run somewhat hotter, the temp might remain more stable as the boiling point of A/F is way, way higher than water. As water turns to steam once it hits its boiling point, hot areas in the cylinder head and turbo are where temps are most likely above waters boiling point and steam doesn't cool well at all. The # 4 cooling mod comes to mind as coolant sure seems to loose some stability in this area.

Pressurized cap helps but is there another way on our engines ??

As A/F has a higher viscosity than water it probably travels through the cooling system slower. As many run underdrive pulleys and others remove 3 of the 6 impeller blades from the water pump, slower running coolant doesn't seem to be a problem. Ed Peters once mentioned coolant flows through our engines faster than ideal, so this also adds some merit to the Popes theory.

Where I live winter temps are often -40c and I can assure you A/F doesn't freeze at this temp. Adding water certainly doesn't lower the freezing point !! -40c is so cold that even having a 1/8" bleed hole in the thermostat will reduce the vehicles heater output so I'm used to cold weather.

I'm not saying the Popes theory is 100% correct but it is worthy of some discussion not just rehashing old norms.

I have many vehicles, so when I decide which one to run this winter, I'm going to run straight A/F and put his cold weather theory to the test. When I put my Super 60 Omni back on the road next year, I'll also give it the 100% hot weather, high boost test.

Thanks
Randy
 
#16 ·
I think one of the biggest things that cause our cars to over heat is not doing the job right.
Sure the mix is important. But this very thread shows there are different ways to mix or not mix to get a desired result. But if you do not get ALL the air out of the system. None of these ways will work worth a darn.
I had issues with getting this right when I did my first head gasket on my Daytona. After starting a since long lost thread and talking to the guys on here. I installed a ,for lack of a better term, burp valve in the hole on top of my water box.

I open this valve and fill coolant system till the mix comes out of the valve.
I then shut valve and top of rad.After which I top of coolant over flow bottle to just between low and high mark.
I then run car till it reaches proper temp and a cycle or two of rad fan.
Shut car down let it cool and suck coolant back out of over flow bottle.DO NOT LET BOTTLE GO DRY.IF YOU LET COOLANT BOTTLE GET SUCKED DRY YOU HAVE LET AIR BACK INTO SYSTEM.
I found that doing this a couple of times purges the system of almost if not all the air. Then take it for a hard run and let cool down again. checking coolant over flow bottle to insure it dose not get sucked dry if there was still air in system.
 
#18 ·
I just run my car with the radiator cap off until it reaches operating temp and opens thermostat. Your coolant level will fall, top off radiator and let run while keeping it topped off until bubbles stop. With car still running put rad cap back on. Top off coolant overflow to full hot mark and shut car off and let cool. Helps to have nose of car jacked up while doing this. Also, if you drill a small hole in the top of the thermostat it helps to bet some of air out as you fill.
 
#20 ·
Since you directed your response to me Randy I'll say this: The folks that formulate antifreeze know more about how it should be used than you, I .... or da pope.

Glhs60 said:
Where I live winter temps are often -40c and I can assure you A/F doesn't freeze at this temp.
... sounds like you've tried this ...
Glhs60 said:
I have many vehicles, so when I decide which one to run this winter, I'm going to run straight A/F and put his cold weather theory to the test.
... sounds like you haven't actually tried this.

So, you've cut and pasted a post by a guy who froze a 50/50 mix coolant ... who lives in washington state .. (lol) and swears by running straight AF thus going against every manufacturer of this product and directions on its proper use.

Got to love trail blazin' .. just be sure to roll up your pants.
 
#21 ·
I've left jugs of A/F and oil outside in the cold and it never froze if this counts.

I use A/F to balance my tires as I don't like external wheel weights.

Its actually the possible "hot weather" cooling benefits that I'm mostly interested in.

Possibly the folks formulating A/F want to sell premix for the same price as pure...

There are many manufacturer recommendations that are not always 100%.

I don't roll up my pants but I do like to experiment, I even use Red Tek refrigerant.

I do mix engine oils against recommendations and and I never torque to yield.

Pope brought up an interesting theory and I will test it.

Thanks
Randy
 
#22 ·
Huh, I never would have thought about running straight antifreeze. Maybe I will try this in the winter to get my truck to warm up faster. 318's just seem to be cold natured. Also, I havent heard anyone mention the "Evans waterless coolant" Seems like this would be a good idea. Probably similar to 100 percent green antifreeze but with more transfer ability. What about that chrysler antifreeze used in the LH cars. [maybe others]. Can that stuff be replaced with the normal green antifreeze without worrying about water pump problems
 
#25 ·
If the system looks clean then there is no need to use chemicals. Just flush it with clean water till everything coming out is clear. If you don't pull the block drains to get all the water out I like to dump a gallon of distilled water through to flush out the tap water.
 
#26 ·
Here is my take on the indiscriminate mixing of coolant types:

In brief, it's not typically a good idea and a system designed to run 'green' should be filled with green. And the same can in GENERAL terms be said for the other colors.

Here are some things to consider if you are into details and a little supposition (perhaps common sense and/or experience) on my part:

Some folks just take the yawn approach to what goes on between consenting chemicals in the steamy privacy of a car's cooling system. It's just not me because of a recent check that was written to the machine shop for aluminum welding services to replace material in some places in a cylinder head that did it. Funny how much aluminum went AWOL in the 30-some years since that engine left the factory, enough to leave gaskets hanging in midair.

Funny? I laughed all the way to Coolant College and did a little Googling.

Modern antifreeze, is 96-percent ethylene glycol, which provides the freeze protection, and four-percent additives...typically. When you dilute that blend 50-50 with water, as the makers intend, you push down the freeze point to minus 34 degrees Fahrenheit. In normal circumstances, you also gain corrosion resistance . . . for a while. The freeze protection is permanent, but the additives are consumed in battle, so to speak.

About half the additive is made of buffers to control acid buildup; the other half is corrosion inhibitors to protect metals.

Perhaps the battle is already going badly in your car. A sticking thermostat can be an early indicator. The next stage: As detritus migrates through the system, it settles in the most confined spaces. If your heater blows cold, uh-oh.

I was hoping that technology, as it marches relentlessly toward obsoleting everything I own, might also have created new antifreeze formulas that would bring forbearance and frustration to the chemicals frolicking under my aging radiator caps.

Of course, no doctor writes the prescription before he considers the patient. The "old" antifreeze technology started in the '60s, improved in the '70s, and was superseded in cars of the '90s by two new technologies. It turns out that an antifreeze transplant into older cars will work fine with one of the new types; the other will probably kill the patient.

The old technology, a.k.a. "conventional," a.k.a. "inorganic," is green in color. Most of what you see on the shelves at Wal-Mart and AutoZone is conventional, including the yellow bottles of Prestone and the white bottles of Zerex.

One of the new types is "organic acid technology," or OAT. It's orange. General Motors pioneered this chemistry starting with 1996 models in the U.S. and using the name Dex-Cool. Ford changed a few models to OAT, then backed away from it. VW, Audi, and Porsche are OAT users, too, but most others have resisted.

Instead of OAT, most new cars now use a "hybrid" antifreeze that's formulated with both OAT and the silicate inhibitors from green (Japanese hybrids have different inhibitors). It comes in too many colors to pretend this type is color-coded. Interestingly, the materials improve for the white plastic overflow bottles of new cars, and they become less yellowing over time, automakers are becoming more venturesome in choosing coolant colors.

The promise of OAT is long-life corrosion protection, on the order of six years/ 100,000 miles for the initial fill instead of the two years/50,000 miles that was typical with the old green stuff. The GM Dex-Cool formula works fine in systems designed for it. But it eats old-style radiators with lead solder, and the inhibitors work too slowly to protect against the sort of corrosion that happens so fast it actually erodes metal-for example, the cavitation likely in the imperfectly designed water pumps of older cars.

"Cars born with green coolant shouldn't be changed to orange," It's also a bad idea to mix the two, although the result doesn't immediately turn into witches' brew.

I theorize that coolant technology is driven by the makers of new cars to solve new-car problems (same with motor oil.) By the time a car gets old enough to be interesting to a collector, the latest antifreeze blends have moved on to protecting newer alloys and gasket materials. Fortunately, the aftermarket lives by catering to older cars.

As for those aging turbo Dodge cars of the 80's and early 90's we're keeping around as playmates, no matter what brand green antifreeze we choose, and no matter how often we replace it, the best medicine is to play often. Coolant down in narrow crevices can become isolated, then overwhelmed by corrosion. Once it starts, the best you can hope for is a stalemate. You can't undo corrosion. To keep protection active in all the crannies, the system needs to be heated and circulated every 30 days. This is by recommendation of the engineers at Zerex.

Obvious question: What about the water we mix in? As mentioned in my original post, coolants are designed to work with "reasonable" levels of hardness and chlorides in tap water. But magnesium and calcium, the hardness ions, unquestionably contribute to scale and deposits, which hurt cooling efficiency. And chlorides are corrosive. Distilled water gets rid of all the worries. (It was $.98 cents a gallon at my local Wal-Mart yesterday. Or you can buy "predilute" coolant already mixed and ready to go.

In my vision of purgatory, I'll be sentenced to changing antifreeze in all my cars, day after day, and some archangel with white gloves and a test tube will be checking the color of my flush water for contaminates. I have to keep flushing until he can't tell the drain-out from the distilled he carries in another tube as the control.

Here in this life, I've always changed my coolant. I'm one of those guys who agonize over details. So the job takes a full afternoon for each car. I drain everything that comes out through the cock, then top up with clear water, warm the engine, and run the heater to circulate fully, then drain again. Repeat twice.

What to do with the drainings? I called the local pollution controllers. Antifreeze? Their book had no mention of it. After thinking a bit, however, they told me to put it out back in buckets and let it evaporate. Rocks evaporate at about the same speed.

Old coolant "hanging up" in the system is a real concern. But we also know that nobody gets it all out.

If you open a drain cock or drop a bottom hose, you might get 50 to 60 percent out. The best machines, the new ones going into Valvoline quick-oil-change shops, get 80 to 85 percent. This is a manageable level of contamination, as long as the new antifreeze doesn't fight with the old.

Don't mix and drive!
 
#30 ·
I always flush my cooling systems out with 100% Distilled White Vinegar. It's cheap, cools 99% as effective as pure water and really cleans out the cooling system. It's safe on our engines in all respects. I never leave it in for more than twelve hours. The car can be used for short trips with no problems. This is an old-skool steam boiler trick that works great. It really gets the heater core and radiator clean. I fill the entire system with vinegar, no water. Don't do it in the cold, obviously. Then flush with the garden hose while running thoroughly. Then mix distilled water with glycol. I also replaced the plug in the water box with a brass petcock to purge the air out.

McMaster-Carr