Engine Cooling System Upgrade

[Byrne H&A]

Owner's Manual prescribes a 50/50 solution of ethylene glycol and water for engine coolant. The ratio of ethylene glycol to water may be increase substantially to 70/30 for a more effective transfer of heat from the engine. I noted the information on a Shell Oil ethylene glycol concentrate container a few years ago and have used the 70/30 ratio since that time. Enjoy!

[Silverbullet]

Ah..... I always thought Water was better for cooling.... and that Less Glycol, more water, would cool better... Also there is "Water Wetter" you can add.

hummmm....

Craig

[ramblinmike]

Ah..... I always thought Water was better for cooling.... and that Less Glycol, more water, would cool better... Also there is "Water Wetter" you can add.

hummmm....

Craig

I've always been told this as well.

[Byrne H&A]

Please read again the original information. The ratio of Glycol to Water is 70/30, which means 2.3 times more Glycol than Water. Glycol is a heat sink and absorbs the engine heat and transports to the radiator. Byrne

[Bitsyncmaster]

Good coolant info here:

http://www.geareddrives.com/Water_Best_Coolant.html

[Spittybug]

and here...http://hellafunctional.com/?p=629

More antifreeze is not necessarily "better". It depends on what your measurement criteria is.

[Rich]

I noted the information on a Shell Oil ethylene glycol concentrate container a few years ago and have used the 70/30 ratio since that time.

You may want to read that label again. The ones I have tell that increasing to 70/30 will increase the boiling point at 15PSI and also lower the freezing point of the mixture compared to 50/50 (normal) mix.

It says nothing about "more effective transfer of heat from the engine".

Can you find more info about this claim from Shell and share it?

Most cars, including D's, run well below the 265degF boiling point (at 15PSI) so bumping up the boiling point will be of little benefit.

Not that there's anything wrong with using 70/30, only that I'd like to see any info about more effective heat transfer at normal conditions where any car normally runs. The manuals in my cars all say 50/50, which is what I run.

Yes, if the engine boils over with 50/50 then the heat transfer goes way down. In that case it means you have other problems with the car besides the coolant mix.

[Nicholas R]

Please read again the original information. The ratio of Glycol to Water is 70/30, which means 2.3 times more Glycol than Water. Glycol is a heat sink and absorbs the engine heat and transports to the radiator. Byrne


You may want to read that label again. The ones I have tell that increasing to 70/30 will increase the boiling point at 15PSI and also lower the freezing point of the mixture compared to 50/50 (normal) mix.

It says nothing about "more effective transfer of heat from the engine".

Can you find more info about this claim from Shell and share it?

Most cars, including D's, run well below the 265degF boiling point (at 15PSI) so bumping up the boiling point will be of little benefit.

Not that there's anything wrong with using 70/30, only that I'd like to see any info about more effective heat transfer at normal conditions where any car normally runs. The manuals in my cars all say 50/50, which is what I run.

Yes, if the engine boils over with 50/50 then the heat transfer goes way down. In that case it means you have other problems with the car besides the coolant mix.

Rich is right, adding more ethylene glycol does not improve the heat transfer coefficient of the mixture, all it does is raises the boiling point as well as lowers the freezing point.

Water alone is better for heat transfer than coolant, the issue is just that it boils at 212 (however as long as the system holds pressure, the boiling point will rise as high as 250 at 15psi). As long as the temperature is below the boiling point, the amount of heat extracted with just water will be higher than a water/coolant mixture. Water wetter is an additive (that is essentially soap) that reduces the surface tension of the water, increasing the contact surface area between the water and whatever is being cooled. Still, again the temperature cannot exceed the lower boiling point of water.

I actually experimented with running water and water wetter in my car after the swap but before I got Ed's radiator. With full airflow through the radiator, the engine temperature was several degrees cooler under the same conditions (temperature measured by the OBDII scanner). Still, in traffic, because the temperature easily reached 225, I didn't like having the water in knowing the low boiling point. If one fan stopped, my goose was cooked. At least with the coolant, the temperature overall was higher by several degrees, but I didn't have to worry nearly as much about the upper boiling point. Then I got Ed's radiator and quit having to worry at all. :)

[Byrne H&A]

Interesting, thank you, probably explains why the antifreeze has not needed replenishing.
I will contact Shell for relative information and will share their reply. Thanks, Byrne

[Shep]

Think of it this way: if antifreeze were better at cooling than water, why would 50/50 be the de facto standard instead of pure 100% antifreeze? ;)

[Byrne H&A]

Spoke with Shell antifreeze specialist and the following is summary of conversation.

1. He said he is very familiar with the DeLorean.
2. Use 50/50 antifreeze/water coolant solution as prescribed.
3. Increasing antifreeze to 60% will start an inversion in cooling and increase coolant temperature. At 70/30 ratio, the coolant will actually
increase 10 F.
4. 50/50 "green" color antifreeze will prevent boiling up to 265 F.
5. Stay with green antifreeze and do not use orange color Dexcool antifreeze as it is for overflow tanks that drain coolant back in system, when cool, preventing air pockets. Air pockets will allow corrosion of aluminum heads.
6. Water will transfer three times more heat than antifreeze but boils at 212 F.
Boiling voids form in the surface of cylinder walls at boiling temperatures of solution forming vapor that interferes with heat transfer.
Antifreeze melts at high temperature forming vapor pockets.
7. Therefore, 50/50 green cooling solution, a boiling point of 265 F and a 15 PSI cap should be sufficient.
8. There are other products in use such a "water wetting agents" that tend to reduce coolant temperature about 10%.
These are not Shell products and additional information is not available there.
9. I mentioned prior Shell reference using 70% antifreeze. He replied, "I know, but don't go over 50/50".

Hopefully this information and advice will broaden our knowledge and cooling system maintenance,
as well as, clarify some facts about heat transfer coolant media. Cheers, Byrne