Nice discussion, but it's wise to remember the manufacturer's recommendations in all this. There is more to antifreeeze than just a lower freezing point. The mixture works better, it transfers heat better and in a more controlled manner, it works in the manner the entire system was designed for. I can tell you from extensive testing of diesel engine cooling systems that pure water overheats easily, it can even boil in hot spots when the entire system isn't at the boiling point, etc. Pure antifreeze doesn't work at all, but mix the two and it's pure magic. We found that a 25% antifreeze to water mix is the minumum (and nearly optimum too) ratio, add more antifreeze as needed for cold climate. And don't forget the supplemental coolant additives - corrosion resistant and anti-cavitation addititives, etc that antifreeze contains. There is no good reason to screw with the mixture - none! There is no advantage to be gained, it isn't expensive maintenance and isn't frequent maintenance either. (Why the heck would you change your coolant mix seasonally? If you have overheating issues in summer, fix them. More water in the mix isn't the answer.) So just run the proper mix and worry about other things like how to get past that next trail obstacle.

 

Don't forget one more thing...your engine, radiator, and all the other miscellaneous components are made of different materials. Pure water can cause electrochemical reactions between those different metals. Sure you can use only water for short terms...but for the long haul use recommended mixes of coolant, waterpump lubricant/antirust, and water. Otherwise, you may have some expensive repair bills when your radiator, water pump, or cheap potmetal housings corrode and leak.

Also remember that antifreeze (ethylene glycol) is poisonous, yet smells and tastes sweet to animals. Ingestion usually causes the liver to shutdown and the animal dies a miserable death. It can be recycled, filtered, rejuvenated and reinstalled back in your vehicle.

Propylene glycol, is less toxic than ethylene glycol and is sold under various brands as a more environmentally friendly solution.

 

Except for this to be a serious issue, those different metals have to be touching. In most vehicles, there is a section of rubber hose isolating one from the other. However, there are two very important mismatched items that do touch and thus require the antifreeze mixture. This is the head(s) and the block. The thin headgasket just isn't enough of an isolator especially when the head bolts connect the two anyway. Good catch, I had totally forgotten that reason for anti-freeze.

 

I think that antifreeze/coolant also lubricates the water pump.

 

Antifreeze actually raises the boiling point of water, so using just water is bad news because your radiator will boil easier...

Using antifreeze lowers the freezing point AND raises the boiling point, it is useful for both the winter AND the summer

 

Antifreeze doesn't contain any lubricant. That's why it's a good idea to add a container. I've heard the waterpump stop squeaking after idling a while with the lubricant. I think I picked the idea up from MotorWeek years ago.

 

that's fine as long at the antifreeze/water/whatever is not electrolytic at all. the probability of that happening is very low (and even if it was pure from the start, i'm sure something will get in there over time that will help conduct electricity). so yes, the original poster was correct, and i forgot about that. "pure" water will allow chemical reactions to take place among the different materials (even if they're not in direct contact).

 

So lets recap... Antifreeze lowers the freezing point AND raises the boiling point, making it necessary year round. Someone said that water had the highest heat capacity known to man, I'm not sure if thats true, the scale is based on pure water = 1 but why would we use oil, other than its lubricating qualitites, if it boiled before the water in our radiators?

I have a question that fits this thread. I flushed my system recently, did the cleaner step with the concentrate bottle of something, ran it, flushed it with water, then filled it up according to guildlines. I went for a drive and came back to let it sit and my overflow bottle was spewing new coolent all over my garage floor :pat: I could hear air bubble moving through the system so I figured that when I had drained it air had made it back into my block and it was finally working its way out, and forcing fluid with it. So my plan was to keep air from re-entering the system by monitoring the level and never letting the overflow res go below the hose, thus keeping air from being sucked BACK in once my system cooled and the pressure was released. Well, it did my best but it didn't seem to work. I kept it above the low level and thought it was fine, but then I heard the air girgles again, almost knocking sound and fluid was spuing out again!

Do I have some sort of hot spot that is surpasing even the coolents boiling point, or do you think I have a leak? I don't see any drips, but where would this air be coming from. Right now I can't have any extra fluid in my overflow, or it will come out when it gets hot!

What do you guys think?

Erich

 

You probably have an air bubble at some high point in the system. Usually it's in the heater core. Set your heater control to its hottest setting, then drive it until the thermostat opens up...this usually bleeds the air bubble out.

 

And remember to use the red Toyota coolant that is non silicated. The green stuff is hard on waterpumps. I've always gotten coupons off the internet to get the red coolant for only a couple dollars more than the green stuff.

 

In many cooling systems, the top of the radiator is actually lower than some parts of the engine that contain coolant. This will create an air pocket in the engine which is sometimes very hard to purge. This is why many engines contain a bleed port somewhere on the block which you are supposed to open when filling the system to allow the trapped air to vent. I have had some vehicles that I had to apply pressure to the radiator fill opening in order to force the excess air out the bleed vent. On many engines, this vent is located just behind the thermostat housing.

 

I dunno about highest heat capacity, but water takes an EXTREME amount of energy to heat up. Water is a little funny, its the only thing known to man that expands when it cools.

 

What's the best way to get a 50/50 mix of water and coolant after flushing your cooling system? I just mix equal amounts of water and coolant before pouring it in, but is there an easier way?

 

That's how I do it, just add equal amounts to a container and then pour it in. Too bad Toyota doesn't sell the pre-blemded stuff.