442craig

Hi Guys,

I know we touched on this before but would love to hear everyones opinion on using "Water Wetter". I am going to finish my engine build (nothing leaks) with finalizing the cooling system. I am wondering what to use in my 4 core radiator. The car is a mildly built 400 roller cam, rockers, forged pistons and edlebrock manifold. I live in Southern California and she is in the garage (don't think I have to worry about freezing) Water Wetter claims a 20 degree temp drop. What mixture should I run? All water? 50/50? 30 percent coolant? A lot of options. Can you run Dexcool in an old car?

Thanks,

Craig

442craig

Found this article. I think this answers the Dexcool question!

http://www.stlaroc.com/features/dexcool.html

Craig

oldcutlass

I use a 50/50 mix of old reliable Prestone and a bottle of water wetter.

442craig

Eric,

Did you notice a drop in temp with water wetter?

oldcutlass

Yes, about 10 degrees and it slowed the rate that the temp crept up at idle. At hwy speeds my temp is a constant 190 with a 180 degree thermostat.

442craig

Sounds simple to me, maybe I'm over thinking this!

Thanks!

Fun71

Below is a lot of info I researched over the years about cooling systems and antifreeze.

As you can see in the first two charts, using a 50/50 mix of antifreeze will depress the freeze point to -34ºF, which I don't think you care about, while raising the boiling point by 15º. The system pressure as dictated by the radiator cap has a much greater influence on the boiling point than the antifreeze does (third chart). The drawback to antifreeze / ethylene glycol is that it can not absorb or conduct as much heat as plain water (fourth chart below). This is where it gets interesting. Note that there is a 33% reduction in heat conductivity with a 50/50 mix and the heat capacity is reduced by ~16%. This means that a 50/50 mix reduces your system's cooling capability, with the trade-off of depressing the freeze point to -34º (for those unfortunate enough to need that level of freeze protection).

Now the last chart is interesting. It shows an increase in cylinder head temperature of 45º for a 50/50 antifreeze mix over water and an associated need for higher octane, reduction in timing, and reduction in torque due to that increased temperature.

The big benefit of antifreeze for those of us in the warm part of the world is its anti-corrosion additives. You could get the best cooling capability by using 100% water but you would not have any corrosion protection, so you would need to use an additive to prevent corrosion. NAPA and other parts stores sell anti-corrosion and water pump lubricants. Another option is to use antifreeze for its anti-corrosion properties, but in a reduced percentage. What I typically do is use ~25% antifreeze, which gives freeze protection down to 10ºF.


freeze_boilchart-1.jpg


Coolantboilingpointchart.jpg

Thermalpropertiesofcoolingsystemmaterials.jpg

performancepropertiesofcoolants-1.jpg

442craig

Wow!

Great stuff, head is spinning! Have you considered Water wetter with all this?

Maybe a 25 percent antifreeze with water wetter is the ticket!

Craig

oldcutlass

Yeah, calling it a coolant vs an antifreeze is a misnomer. I've always kept the 50/50 or 40/60 of antifreeze/water in my engine more for not wanting to add or remove any with the change in season. I also like it for the anti-corrosion benefits of my aluminum radiator.

442craig

I'm running a 4 core, stock radiator so heat disapation is priority. I probably wouldn't see temps below 45 degrees here. (too chili for a convertible anyway!) I think running a higher water mix would help with this and still have enough antifreeze for anti corrosion.

Maybe an anti corrosion additive would help. Any recommendations on an additive?

oldcutlass

Like Fun71 stated above, since your temps are mild and your not really running in the winter, 30% is probably fine. I run my car all year round, and the area I'm in can get well below freezing on occasion, so I play it safe. In my youth while living up north, I've had a radiator freeze at hwy speed.

Fun71

I should point out that most cooling systems are designed to have excess cooling capacity, so the cooling loss due to antifreeze vs. water is offset by the excess capacity. If the system doesn't have that excess margin, then straight water may cure overheating issues.

I would try 25% antifreeze and see how that works first. Then if you see some elevated temps try water + water wetter and an anti-corrosion additive. There were some posts on ROP several years ago about a good additive but I can't remember what it was. It was recommended by drag racers who ran straight water in their systems. Maybe an internet search or posting the question to some racers would be in order.

My local summer temps run 115 and above and my system does fine with 25% antifreeze instead of straight water. I have a Craig high efficiency 4 row radiator core attached to the factory 3 row end tanks, so this may be comparable to your factory 4 row radiator. We'd have to compare the number of tubes and number of fins-per-inch to see how close they actually are, though, as there can be extreme differences depending upon the manufacturer (not all radiators are made the same). The capacity of my system is 4 gallons so it's simple for me to dump in 1 gallon antifreeze then top off with 3 gallons of water.

442craig

Thanks Kenneth,

I am going to go with 25 percent antifreeze and water wetter. We'll see how it goes. I might add that I didn't have any heating problems in the past, just want to have the best cooling I can get for this overpriced noise maker!!!!

Craig

brown7373

There was an interesting article a few months back on this question. What it concluded is pure water does yield lower temperatures on the gauge, but not necessarily lower engine temperatures in the engine. Has to do with the surface tension of the water. Pure water doesn't remove as much heat, and therefore stays cooler and yields a lower gauge temperature and fools many in to thinking they are running cooler. I think Water Wetter lowers the surface tension and therefore removes more heat from the engine. I think ain't-freeze also reduces surface tension in addition to having the rust and corrosion inhibitors.

I don't have any problems with running hot on any car I own now or in the past, assuming the radiator and clutch fan operate as designed and run a 50/50 mix. Granted, most are stock or mildly modified, but I run A /C and live in south Florida.

Fun71

I'd be interested in reading that article. Where was it? Do you have a link?
Well, if the coolant is cooler, then they are "running cooler" as that is what we measure as an indicator of engine temperature.
So I wonder what is the article was measuring to indicate engine temperature? Oil temp or ??

I don't think that is accurate at all. See the info above on the heat capacity of water vs glycol coolant. This means that water can absorb and transfer more heat than water/glycol coolant mix.

And then compare the actual measured cylinder head temperatures of plain water vs. glycol/water coolant and you see that the head is much cooler with water:

brown7373

I was out of town for a while and had limited internet access.


I think the article was in either Hemmings Classic Cars or Muscle Machines a couple months back, but I don't have a copy of it. But there was an interesting letter written to Ray in the May 2014 Hemmings Muscle Machines, where his reply to pinging is "Excessive heat in the combustion chamber usually does not translate to elevated coolant temperatures, and this fools many people". The article of a few months back explained that the coolant with a higher surface tension didn't transfer the heat away (and raise the coolant temperature) from the engine and therefore showed as okay on the gauge, but the engine was actually too hot.


You want the coolant to get hot if it is effectively removing the heat from the engine, and then have enough cooling capacity in the radiator to cool it down.


Anyone have a copy of that article? I usually throw my magazines away after I read them, otherwise you might see me on Hoarders.