100% coolant ?

[Aaron]

I just had a local VW mechanic recommend running coolant at 100%, ie. not diluting it at all...what do you think

[Deaffy]

When I had watercooleds, I always ran 100% antifreeze. That was more a lazy factor than anything else, since I didn't always have distilled water on hand.

From what I understood, adding the water merely helped to lower the freeze point of the coolant. I had always lived in places with fairly mild winters, so I wasn't too concerned with that point.

[gears]

How does adding water make the coolant freeze at a lower temperature? Isn't it the other way around?

[Deaffy]

I just grabbed this off of a antifreeze manufacturer's site ...

[earthmuffin]

I always go 50/50. If the manufacturer says do it, you might as well. I figure they must not be lying about the benefits of a 50/50 mix because if you mix 50/50 you are actually buying less anti-freeze which means they sell less product, blah blah blah, you get the point. I admit to knowing nothing about H2O chemical molecular heat transfer inhibiting properties, so I leave my decision up to the professionals.

[jeggers]

i was reading last night that anything more than 60% coolant will make the sensor in the coolant tank light up your dummy light on the dash

[Stanagon]

You do NOT want to run with more than a 60:40 coolant:water ratio. It actually makes the coolant LESS effective if the concentration is too much.

I'd stay away from that "local VW mechanic" for water-cooled work.

[gears]

VERRY interesting. I suppose changing the coolant annually is where I failed. (Let's see, how many years has it been? No wonder my coolant / thermostat froze.)

[Aaron]

VERY, VERY interesting!!! Thanks for all the feedback...

[sbclayton]

There's one more vital bit of info here.

I don't know how similar VW's are to BMW's, but I ran 100% antifreeze (albeit "the green stuff") in my '74 BMW 2002. It quickly developed a major overheat condition.

When the shop mechanic got everything apart, the cause was obvious - the corrosion inhibitor salts had precipitated out of the antifreeze solution and completely plugged the bottom of the radiator - it was solid crystals!

This happened in warm weather - the only kind we usually get in Florida. Don't know if that had anything to do with the antifreeze plugging the radiator, but the mechanic told me that was a common problem and the main reason why !00% antifreeze should never be run.

Steve

[zerotofifty]

With 100% coolant, your cooling system will not work correctly. 100% coolant will not cool as well. The antifreeze actually has much worse heat removal properties than water. The antifreeze is needed however for three reasons.

1. It prevents the mix from freezing. the more anti freeze, the colder you can go without freezing, many bottles will list the minimal temp, at a given ratio to water. In most normal climates, 50-50 mix will protect from freezing even during the coldest weather. (not sure about a cold night in the south Pole!) Probably no probelm ever in the 48 states.

2. It prevents boil over. the antifreeze increases the temp that the mix will boil, the more antifreeze, the more boil over protection. The radiator cap determins the pressure that the cooling system can handle, until it vents into the overflow tank. Once the mix begins to boil, the cap does its job, and vents (if it didn't vent, and it boils, the system would explode at the weakest part) an increased boiling point allows you to run hotter, while not increasing pressure.
More boil over protection will not make you run cooler however, unless you are already boiling over, but things such as other engine problems, or a faulty radiator cap will also cuase boil over.

3. the anti freeze also has anti corrosion chemicals. These are what are so importnat for our Vanagon heads. It is these chemicals that deplete over time, and is why antifreeze must be changed, these anti corrosion chemicals get used up over time.

the Ethylene Glycol chemical is the stuff with effects number 1 and 2 above (antifreeze, and antiboil) this chemical does not wear out, but when the anit corrosion stuff goes (in a year or two) stuff will start to corrode.

the coolant mix main job is to take heat from the engine, and move it to the radiator, where the mix is cooled. Pure antifreeze is not a very good heat conductor, water is an excellent conductor of heat. If you run pure antifreeze, your engine will run hotter. (the engine runs coolest with pure water, but pure water would boil away, corrode the metal, and freeze when it is cold)

the factory (see bently manual, or owners manual) recommends 50 -50 mix in colder climates, and in warm climates 60 (water)-40 (antifreeze) in hot climates. For most 48 state driving 50-50 is a good choice, and change it out every year or two. be sure to use phosphate free antifreeze as per the factory.

Using pure antifreeze will in most cases cause running too hot, and wastes your money. Distilled water can be had at many stores, it is sold for steam irons. If you do not have hard water in your area, tap water can also be used. Some antifreeze these days is also sold pre-mixed at 50-50 ratio.

I recommend you switch to 50-50 or 40-60 as per the factory recommendation, depending on your climate.

good luck. dave 86 Vanagon

[70 140]

You can get distilled water from that pail in your dehumidifier. And since it has no minerals in it, it will keep for ages in a glass bottle. Around here I could collect a lifetime supply in about a month. I always forget about saving it so I usually just put a bunch of water in a pail and let it sit for a week. This doesn't remove the minerals, like distillation does, but it lets some of the chlorine or flouride (common in tap water) evaporate off.