Coolant system - humid tropics - recommendations?

[boxer_inv]

Hi

After success with my welch plug replacement, "Dorothy" is back up and running with some lovely fresh water circulating in her coolant system.

Question: What coolant additive should I get into her? How much?

Bearing in mind that I'm in the tropics - Cairns OZ - so there is NIL requirement for any type of anti-freeze prevention per-se.

I've been conscious of not just posting trigger happy questions and wasting everyones time, so - YES - I have searched these forums for some answers...but it seems there is quite a range of coolant theories out there, mostly dependent on where one lives. Don't get me wrong, i have some idea of what I need, but thought I'd try for some more input...

I guess I'm seeking to have some recommendations on what (if anything?) is going to give me the best cooling in an average ambient temperature of, say, up to 34 degreesC (95F) but at HIGH humidity levels.

Regards, Rob.

[Andydodge]

Rob, soluable oil is supposed to be helpful/required in the older coolant systems as the SO apparently helps the water pump bearings........eventually when I get the 230 six in the P11 I intend to delete the fan and run an electric fan on the front of the radiator, I have a 180degree thermostat as suggested by our elders(lol) in it at present and with the stock radiator and engine driven fan the 201 runs at 180-190 all day, I'm in Grafton, temperate zone I suppose.........andyd

[Dennis Hemingway]

I live in the Mojave Desert area of Calif. where the summer temp reaches well over 100F mark. I run a 50/50 mix of antifreeze with 1 bottle of WaterWetter in my vehicles. The 48 Plymouth has a 180degree thermostat and it runs at 180-190.

Dennis:cool:

[Plymouthy Adams]

antifreeze/coolant is recommended in a mix of 50/50 to prevent most freeze conditions and protect against boil over in the summer. This ratio of mix is also there to protect the system agains rust/corrosion and lub the water pump...

I think you looking at 15 quarts without heater, 16 with..so you will need approx two gallon of antifreeze..

[PatS....]

I'm betting if your local auto supply store even stocks anti-freeze that it would be there for the reasons Tim mentions.

In Canada Tim's reasons are why we use 50-50 mix year round in everything.

+30 or -30

[greg g]

anti freeze coolant as sold in most areas also provides for anti corrosion portection and water pump lubrication. Both of those components are available seperately as well. If you have a mopar with a grease fitting on the water pump, that obviates the need for additional lube. So if you live where it never freezes, you could run water and the anti corrosion stuff.

Plain water doeas a better job of absorbing and transferring heat then the coolant water mix, and might do a better job of keeping your engine cool. However the coolant water mix has a higher boiling point so there is a trade off there. Me, I don't run my car in

the winter and it goes in a garage that deosn't go below freezing. so I run 1 gallon of anti freeze (new water pump with no grease fitting) and fill the rest with water, about a 75/25 mix, never seen over 190 on the gauge except when I sat idling for 45 minutes waitig for a customs check coming home from Canada.

[Don Coatney]

I have been told stories (on this forum) of people filling the radiator with no water but using engine oil only instead. I have never tried this nor do I have plans to do so. Anyone know the heat transfer rate of engine oil compared to water? Rust bunnies in the engine water jackets could sure be reduced using engine oil but the risk of fire in a front end collision would be grossely increased.

[Plymouthy Adams]

if one could find a public source and the price was within reason (of which I think you would find outrageous) the cooling oil as used in avonic electronic systems is both fire resistant and a di-electric.

[Don Coatney]

if one could find a public source and the price was within reason (of which I think you would find outrageous) the cooling oil as used in avonic electronic systems is both fire resistant and a di-electric.

PCB free too?

[greg g]

didn't some stationary and or marine diesels run light oil for coolant.

[TodFitch]

While it does not get as hot here as where Dennis is, I've lived in the desert in the past. I run 50/50 mix of water and ethylene glycol in my 1933. The only time I've had an issue with overheating has been when the radiator core was plugged up.

I am not sure how much difference the high humidity makes... Heat transfer from the coolant to the air should be proportional to difference in temperature between the two media. Seems like the air flow through a radiator should be enough that the delta temperature of the air (in to out through the radiator) should be small. On the other hand, you can tell by just placing your hand downstream of the fan that the air has been heated considerably so maybe the delta T on the air is enough to give a sizable temperature gradient from the front to the rear of the radiator.

I believe that the higher the humidity the more heat it takes to change the air temperature. If that is true then the temperature rise of the air across the radiator would be less, the delta temperature between the coolant and average air temperature would be higher and the radiator would conduct more heat from the coolant to the air. So basically the radiator would work better in the jungle than in the desert with the same temperature. But the difference would probably be minor (or I might have the latent heat versus humidity wrong backwards from what it should be).

The efficiency of the radiator, as stated above, gets better the higher the temperature difference between the coolant and the air. So the question comes down to using water (higher specific heat) versus an "anti-freeze" solution (higher boiling point). I suspect either way would work but I like having the higher boiling point working toward higher efficiency on the radiator. I haven't run the numbers but it just feels better to me. And the car typically runs cool even when the ambient temperature is in the 30s (Celsius). Its been a while since I've driven the car when the ambient temperature has been in the 40s (Celsius) but I don't recall having any issues with the car. With myself feeling way to hot and needing extra fluid, yes. But the car was fine.

By the way, I assume that you are alert enough to convert any gallons posted by someone in the US using the US measure rather than the old British Imperial gallon measure that is probably better known in Australia.

[Normspeed]

I run 50/50 antifreeze in all my vehicles. Corrosion protection and good cooling too. Not much chance of a heavy freeze where I live, but I've seen it down to 18 F. overnight. Daytime it's 95 to 100 degrees out, and when I'm brave enough to climb into a black car with no air conditioner, she runs right at thermostat rating. I have a 180 in there.

[boxer_inv]

Thanks for your comments.

I note it was mentioned that a 100% water coolant will run slightly cooler than with the additive, and that is interesting. Prior to my 'de-crud' work on the engine, she ran at about 195 or so fairly consistently, only rising to about 200 when at lights etc.

On my run on Sunday, the reading was markedly lower - about 180 rising to 190 at the most when sitting.

All in all, I think that given the lubricating qualities of the coolant additive, its obviously better to run with, than without, so I'll get some in there.

Another question though - would it be a good time to de-scale and flush the radiator out with an additive? I mean, prior to putting the coolant in there and leaving it alone.

Cheers,

Rob.

[boxer_inv]

By the way, I assume that you are alert enough to convert any gallons posted by someone in the US using the US measure rather than the old British Imperial gallon measure that is probably better known in Australia.

Yep - got it covered!! I'll admit, its not unusual for me to be running one of those universal internet conversion tools simultaneously when reading this forum, just to help with the essential numbers. Also helps me post my question in terms that you all can understand too!!

[chopt50wgn]

Ever tried Evans coolant? boiling point of 375degF, eliminates vapor barriers inside the block, lifetime coolant, low pressure running, totally compatible with all metals, eliminates electrolysis. I have it in all my daily drivers and my hot rods.