Bongo Fury

Ron Miel wrote:Hembremacho - you need water in the correct proportion in your coolant mix, to properly conduct engine heat to the radiator. Coolant concentrate is not as good a heat conductor as water.

Really sorry - can you explain that a bit more. How do you work that out?

Andrew

Mines protected to -30 and if it gets that cold then i aint going out anyways

g8dhe wrote:Umm, Wind Chill applies only to the human body. Its the reduction in temperature due to evaporation of moisture, so unless your radiator is continuously loosing water which is being evaporated away then the temperature of the metal will be the same as the temperature of the air blowing past it. For the full details the Wikipedia entry is quite through.

NOW I'm confused!

Andrew

hembramacho wrote:

Ron Miel wrote:Hembremacho - you need water in the correct proportion in your coolant mix, to properly conduct engine heat to the radiator. Coolant concentrate is not as good a heat conductor as water.

Really sorry - can you explain that a bit more. How do you work that out?

Andrew

I didn't work it out Andrew. It's physical fact. The coefficient of thermal conductivity (ability to absorb and carry away heat) of water is 0.58, and that of ethylene glycol is 0.25. If not, manufacturers of coolant concentrate would not tell you to mix it with water at all - think how good for sales that would be!

http://www.engineeringtoolbox.com/therm ... d_429.html

you could split your rad,dont forget windchill factor,it could be minus 5 but face your motor into the wind,and that could become minus15

Surely windchill factor relates to humans rather than cars? The actual temperature is what it is. The wind would have to be at minus 15 to cause minus 15 worth of freezing. Cooling may of course happen more rapidly if the radiator is not sheltered as residual heat will disappear more rapidly.


Frank

Ron Miel wrote:

hembramacho wrote:

Ron Miel wrote:Hembremacho - you need water in the correct proportion in your coolant mix, to properly conduct engine heat to the radiator. Coolant concentrate is not as good a heat conductor as water.

Really sorry - can you explain that a bit more. How do you work that out?

Andrew

I didn't work it out Andrew. It's physical fact. The coefficient of thermal conductivity (ability to absorb and carry away heat) of water is 0.58, and that of ethylene glycol is 0.25. If not, manufacturers of coolant concentrate would not tell you to mix it with water at all - think how good for sales that would be!

http://www.engineeringtoolbox.com/therm ... d_429.html

Sorry - you misunderstood (I think). What I meant was how do you work out the correct proportion of water in your coolant mix.

Cheers

Andrew

hembramacho wrote:Sorry - you misunderstood (I think). What I meant was how do you work out the correct proportion of water in your coolant mix.

Cheers

Andrew

Oh yes, sorry Andrew. I did misunderstand - mainly missed it because I had quoted the manufacturers' recommendation (50/50) in the first para.

BTW, thermal conductivity is closely related to the more complex "thermal capacity", which should more strictly be used in this context, and I've seen relative water/ethylene glycol data for that somewhere - will see if I can find it again.

Meanwhile, two other factors against 100% ethylene glycol concentrate are 1.) it's highly inflammable, and 2.) it's highly viscous below about minus 10-12 C.

From: http://www.answers.com/topic/ethylene-glycol

"Pure ethylene glycol has a specific heat capacity about one half that of water. So, while providing freeze protection and an increased boiling point, ethylene glycol lowers the specific heat capacity of water mixtures relative to pure water. A 50/50 mix by mass has a specific heat capacity of about 0.75 BTU/lb F, thus requiring increased flow rates in same system comparisons with water. Additionally, the increase in boiling point over pure water inhibits nucleate boiling on heat transfer surfaces thus reducing heat transfer efficiency in some cases, such as gasoline engine cylinder walls. Therefore, pure ethylene glycol should not be used as an engine coolant in most cases."

Ron Miel wrote:From: http://www.answers.com/topic/ethylene-glycol

"Pure ethylene glycol has a specific heat capacity about one half that of water. So, while providing freeze protection and an increased boiling point, ethylene glycol lowers the specific heat capacity of water mixtures relative to pure water. A 50/50 mix by mass has a specific heat capacity of about 0.75 BTU/lb F, thus requiring increased flow rates in same system comparisons with water. Additionally, the increase in boiling point over pure water inhibits nucleate boiling on heat transfer surfaces thus reducing heat transfer efficiency in some cases, such as gasoline engine cylinder walls. Therefore, pure ethylene glycol should not be used as an engine coolant in most cases."

So would it still be OK to just top up with blue ethylene glycol antifreeze into the header tank just to make sure it's OK for winter?
Does the OAT, etc issue still come into play, or is blue OK to top up with blue?

Thanks again

Andrew

hembramacho wrote:So would it still be OK to just top up with blue ethylene glycol antifreeze into the header tank just to make sure it's OK for winter?
Does the OAT, etc issue still come into play, or is blue OK to top up with blue?

Thanks again

Andrew

There are two problems for you there, Andrew:

Anti-freeze protection only measuring -15 C is actually quite a low concentration, so it will be very difficult to get enough in via the header tank, to make much difference. That means, unless you do at least a partial, but substantial, drain down, top up with neat concentrate and re-bleed, you've not only got marginal antifreeze protection but, I would guess, your corrosion inhibitors will only have perhaps a years total effective life.

Also, if it's bluey/green, as opposed to pure blue, what's in there might not be a simple ethylene glycol solution anyway. It could well be a hybrid (silicated) OAT such as "green" Comma G48, for example - or it might be a mix of "straight" blue ethylene glycol and something like G48 green. Either way, you'll have no way now of knowing how long the stuff will last - the main penalty of mixing coolant chemicals. You could keep measuring specific gravity (which is what your "antifreeze tester" simply does) and that might give some idea of anti-freeze protection in a few months time, but you'll have no idea whether it's still giving corrosion protection or whether the big sludge up has started. Only safe course is bite the bullet, get it flushed out, and refilled with either 50/50 blue 2-years coolant or, say, 50/50 Carplan Premium Red, Comma G30, or Mazda FL22/ELC (all unsilicated) 3 years coolant, and of course properly bled: http://www.igmaynard.co.uk/bongo/forum/ ... b9#p459017

Gosh this is complicated!

Water has a very good Specific Heat Capacity and is excellent at carrying heat away from the hot bits of an internal combustion engine in the appropriate temperature range (75-100Celcius).

Unfortunately it goes solid below 0Celcius and can be quite corrosive. Ethylene glycol is miscible with water and lowers it's freezing point in proportion to the concentration.

Everything else added to "antifreeze" is intended to deal with corrosion.

There are different schools of thought as to which anti corrosion additives are best.

I don't know if Organic Acid Technology means OAT. But I'm in Yorkshire.

Just remember Ethylene Glycol is very TOXIC if ingested! That goes for any pets too! Please be very careful if you are changing /topping up your antifreeze/anticorrosion agent.

M 80NGO wrote:Mines protected to -30 and if it gets that cold then i aint going out anyways

I am using 50% OAT silicate free Red coolant...... down to -34 per makers specs....

Jaws wrote:Gosh this is complicated!

Water has a very good Specific Heat Capacity and is excellent at carrying heat away from the hot bits of an internal combustion engine in the appropriate temperature range (75-100Celcius).

Unfortunately it goes solid below 0Celcius and can be quite corrosive. Ethylene glycol is miscible with water and lowers it's freezing point in proportion to the concentration.

Everything else added to "antifreeze" is intended to deal with corrosion.

There are different schools of thought as to which anti corrosion additives are best.

I don't know if Organic Acid Technology means OAT. But I'm in Yorkshire.

Just remember Ethylene Glycol is very TOXIC if ingested! That goes for any pets too! Please be very careful if you are changing /topping up your antifreeze/anticorrosion agent.

And the Antidote is WHISKY..

Cheers

We lost our coolant when the rear heater matrix split last winter, we were exposed to temps of -20 for a prolonged period. Since then we have had the coolant changed (when replacing the heater matrix) and hopefully will be OK this winter. That said I intend to run the van more this winter, even when it is really cold and icy, in order to get more latent heat into the van. I also intend to insulate (in particular below the rear heater matrix) to prevent the ground temp from making too much of an impact. If I thought I could get awat with it, I would make it up a hot water bottle, but I think my wife and kids would ridicule me!!!!! Hopefully insulation, running, and the correct coolant mix will do the trick this year.

g8dhe wrote:Umm, Wind Chill applies only to the human body. Its the reduction in temperature due to evaporation of moisture, so unless your radiator is continuously loosing water which is being evaporated away then the temperature of the metal will be the same as the temperature of the air blowing past it. For the full details the Wikipedia entry is quite through.

That's not correct. It may be one of the reasons humans are chilled by wind, but it's not the only (or even the main) one. After all, humans are not perspiring when very cold. Perspiration is intended to take advantage of (latent heat of) evaporative cooling to cool humans when their bodies are overheating. This evaporation is increased when wind blows over the wet surface, preventing the build up of moist air local to the surface which would otherwise reduce the rate of evaporation.

No, it is the prevention of build up of hot air local to the surface of the 'hot' object that is the main cause of 'wind chilling' of humans in ccold weather, and of all objects (perspiring or not) generally. By constantly stripping this local 'insulating' layer of air away, and taking heat with it, a steeper temp. gradient between hot surface and cold ambient air is maintained and heat flows from hot to cold at a faster rate.

So Bongos can indeed experience windchill I fear, if the wind is allowed to get at them.