Overheating Information

[TerryShugart]

Thanks Winston for posting the link. Interesting but my 2310 has a water pump and pressurized cooling system. I would agree with the original poster that a clean and functioning cooling system should not have an issue with a 70/30 mix. Keeping in mind that that is water to glycol. That mix would give you a temp range (from freezing to boiling) of -34f to 265f. The 50/50 mix is -84 to +276. You don't get 100% glycol in the typical jug of antifreeze. A 50/50 mix of the typical jug with water will get you the 70 water to 30 glycol mixture.
Terry

 

[reb]

Thanks Winston for posting the link. Interesting but my 2310 has a water pump and pressurized cooling system. I would agree with the original poster that a clean and functioning cooling system should not have an issue with a 70/30 mix. Keeping in mind that that is water to glycol. That mix would give you a temp range (from freezing to boiling) of -34f to 265f. The 50/50 mix is -84 to +276. You don't get 100% glycol in the typical jug of antifreeze. A 50/50 mix of the typical jug with water will get you the 70 water to 30 glycol mixture.
Terry

Where did you get the temperature range for a 70/30 mix? My information says that will freeze above zero degrees F.

Ethylene Glycol Heat-Transfer Fluid

 

[Ginormous]

Where did you get the temperature range for a 70/30 mix? My information says that will freeze above zero degrees F.

Ethylene Glycol Heat-Transfer Fluid

I compared the boiling and freezing numbers quoted on the back of a Prestone antifreeze 50/50 mix bottle to the numbers on the website you gave.

Prestone 50/50: freezing -34 F/boiling 265 F
Website 50/50: freezing -36 F/boiling 225 F

I just found a Peak antifreeze bottle, and it matches the Prestone bottle. The freezing numbers are close, but the boiling points are way off. The "Engineeringtoolbox" website has a very authoritative name, but I guess this is a reminder that we shouldn't believe everything we read on the internet.

This is a good warning that the 30/70 mix will not for people like me because it will freeze at about 0 degrees F. Have to remember to change it...

 

[Ginormous]

Found this short but informative discussion of the freezing point of water-glycol mixtures...
Don't Fill Her Up with Antifreeze, Alaska Science Forum

 

[reb]

I compared the boiling and freezing numbers quoted on the back of a Prestone antifreeze 50/50 mix bottle to the numbers on the website you gave.

Prestone 50/50: freezing -34 F/boiling 265 F
Website 50/50: freezing -36 F/boiling 225 F

I just found a Peak antifreeze bottle, and it matches the Prestone bottle. The freezing numbers are close, but the boiling points are way off. The "Engineeringtoolbox" website has a very authoritative name, but I guess this is a reminder that we shouldn't believe everything we read on the internet.

...

Interesting. The boiling point is related to pressure. I wonder if the manufacturer is referring to a pressurized radiator and the website is referring to an open vessel. We all know modern engines can operate at higher temps than 225 without boiling over. The temp sensor in our Yanmars is set for 238, as I recall.

 

[TerryShugart]

I stand corrected. The numbers I gave where for a 50/50 antifreeze mixture and a 70/30 mixture.
Terry

 

[Ginormous]

Ah, but it's the things we don't read that get us. The writing on the Peak and Prestone bottles indicate that these figures are with a pressurized radiator with a ~15psi cap. The 225 degree figure is with atmospheric pressure. That website is giving the specs on the antifreeze solution all by itself.

Good point! Increasing pressure at low temperature would also increase the freezing point BUT lucky for us, when it's cold it's not pressurized.

So do our Yanmars' cooling systems pressurize? I think the answer is yes...

 

[California]

So do our Yanmars' cooling systems pressurize?

Sure. I think Yanmar's spec (Metric) is 13-something psi and a 14 psi cap spec'd for 70's Datsun is the easiest replacement.

I like the lever-release style radiator caps, they seem safer.

Comment - this isn't rocket science, especially the two cylinder Yanmars. These are just one generation evolved beyond open-tub cooling reservoir like a 1920's stationary engine. (well maybe overstated a little. )

For lubricants use modern diesel-rated stuff, for everything else the first stab at finding generic service parts should be 70's Datsun (or Subaru, Honda, etc) including the oil filter, radiator cap, oil and temp sensors, etc. Yanmar designed these early ones to be supportable in all corners of the world and used generic parts for a lot of the maintenance items. The air filter is the only unique design among maintenance parts that I have encountered. Oh and the headlights - shared only with some brand of snowmobiles (Yamaha??) as I recall.

 

[284 International]

One other factor that may be at play here is the specific heat of the different solutions of antifreeze. Water has a very high specific heat-it holds a lot of energy compared to other materials. The ethylene glycol in antifreeze holds less energy at a specific temperature than water does.

Using high concentrations of antifreeze raises the boiling point and lowers the freezing point, but it's deceptive, since it takes less energy to get the solution up to that temperature. It takes a larger volume of antifreeze solution to absorb a set amount of heat than it does straight water. That extra capacity to hold heat may keep localized boiling in hot spots, and better keep the radiator cap from boiling over.

 

[Ginormous]

Comment - this isn't rocket science, especially the two cylinder Yanmars. These are just one generation evolved beyond open-tub cooling reservoir like a 1920's stationary engine. (well maybe overstated a little. )

I have heard it said that "even rocket science isn't rocket science anymore." Even so, with all the this talk of specific heats, pressure induced changes in phase transition temperatures, etc. it's a bit more science-ee than we usually get. :thumbsup: