Coolants - Pick The Right One!


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I don't have to explain you what exactly is Coolant and why it is needed. But to reiterate, let me explain it here. A coolant is a fluid which flows through a device (read engines) to prevent its overheating, transferring the heat produced by the device to other devices that use or dissipate it. So an ideal coolant has high thermal capacity, low viscosity, is low-cost, non-toxic, and chemically inert, neither causing nor promoting corrosion of the cooling system. Coolants can be classified to following types:

  1. Gases
  2. Liquids
  3. Molten metals and salts
  4. Liquid gases
  5. Nanofluids
  6. Solids
I will limit the scope of this thread to Liquid Coolants.

The most common liquid coolant is water. In a typical automobile engine using liquid cooling system, the water is filled in to the radiator. Normally water contains lot of chemical substances, which makes its pH to vary depending on the source. It is completely good to use a pH neutral water in radiator. However, it is always tough to guarantee a neutral pH for water, though it is defined theoretically. Depending up on the acid/alkaline property of the substances in the water being used, radiator, engine block, cylinder head etc. can face a threat of corrosion. This is were Coolants are useful! Following are the major advantages of mixing coolant:


  1. Acts as a corrosion inhibitor. corrosion inhibitor is a chemical compound that, when added to a liquid or gas, decreases the corrosion rate of a metal or an alloy.
  2. Acts as an antifreeze agent. An antifreeze agent prevents a rigid enclosure from undergoing physical stresses and catastrophic deformation due to the expansion that occurs when water turns to ice.
  3. Increases the boiling point of the water. With higher boiling point, water can be raised to considerably higher temperatures (above 100 degrees Celsius) without introducing high pressures within the container or loop system.

Be informed that coolant mixes are toxic and sadly, is a cause for environmental pollution. Coolants are color coded to identify coolant type according to the chemical compound being used. There are 3 types of coolants, based on the color:

Green/Yellow/Blue Color

These coolants are glycol based products and contains ethylene glycol, diethylene glycol, or propylene glycol. Silicates and Phosphates are also added to the mixture to prevent corrosion. ethylene glyco and diethylene glycol are highly toxic in nature. However propylene glycol is relatively safe and is used widely because of this reason. propylene glycol can increase the boiling point of water to 187 degree Celsius. These type of coolants need to be replaced completely once in an year.

Orange/Dark Green/Pink

These type of coolants are Organic Acid Technology (OAT) based products containing ingredients as sebacate, 2-Ethylhexanoic acidm, and other organic acids. These are Organic compounds and hence is very environmental friendly. Silicates and Phosphates are not used in these type of coolants (except in the case of Toyota's pink extended-life coolant, which adds a dose of phosphate to its extended-life OAT-based antifreeze). Though normally these coolants are colored either Orange or Pink, Honda has an extended-life OAT coolant that is dyed dark green and does not contain 2-EHA.

The corrosion inhibitors in OAT coolants are slower acting but much longer-lived than those in traditional coolants. Consequently, OAT coolants typically have longer a recommended service life. OAT coolants offers highest life and need to be changed only once in 5 years or 240,000 km (150,000 miles).

Red

These type of coolants are built with the Hybrid Organic Acid Technology (HOAT) formulation or better knows as G-05 (e.g., Zerex G-05) This formulation also uses organic acids, but not 2-EHA (different organic acids are used). Hybrid OAT coolants add some silicate to provide quick-acting protection for aluminum surfaces. Silicate also helps repair surface erosion caused by cavitation in the water pump. Hybrid OAT coolants are currently used by many European vehicle manufacturers as well as Ford and Chrysler and claims to have an extended service life of five years or 240,000 km (150,000 miles).

PS: DEX-COOL specifically has caused controversy.

So one final question, Which coolant should I pick? The safe answer is the type specified by the vehicle manufacturer. Many antifreeze suppliers have introduced Universal Coolant or Global Coolant products that are one-size-fits-all coolants claimed to be compatible with any new vehicle cooling system as well as older vehicles. One very important point to keep in mind here is that universal coolants and extended-life coolants are not lifetime coolants. The corrosion inhibitors in all types of coolant eventually wear out and must be replenished by changing the coolant. Leave the old coolant in too long and the cooling system will experience corrosion problems. Also, not that it is not advisable to mix different type of coolants, though manufactures tend claims that they will do no harm.


Source: Various resources.
 
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The link to DEX-COOL controversy in the above post is broken. A google on this subject will point to links from consumer forums and review sites. Since I don't want to put the links to an external forum, request you to do a google on this subject, if you are interested to know further.
 
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The glycol based aka the gree coolant was widely used after the water . Water vapourises so soon , corrode parts and freeze in low temp.

Green one is widely used till now.

this one has Low life compared to all.

red and pink and blue liquids have surface in recent years .

Still many do not know about its importance. These can be called as kinda performance coolants . better life and absorb some what more heat than other.


Practically any coolant can be used for your car. Just replace according to time.

Brand value do matter in this. I prefer using wurth than anyother in this case.
 

Akash

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What are these blue pink and green liquids? Sorry, but i am unaware of these names.
Btw, i dont think water is used as coolant in modern cars. I remember seeing some kind of thing(coolant spec), on the filling cap.
 
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Blue, Yellow, Pink etc... are various colors given to the Coolants to identify the chemical combination and coolant type. These colors are obtained by adding harmless dyes to the coolant solution.

For eg: if you see a green color coolant in your radiator, then it falls to the first category mentioned above, which is a glycol based product.

You are correct, modern cars doesn't uses water alone. Coolants are infact a mixture of the chemical / organic compunds dissolved in water. This is done for the reasons mentioned above.
 
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Very informative thread Shynish.

I think in my punto, the coolant is thick and light yellow color. I think the replacement frequency mentioned is 2 years (I have to verify). I think its Paraflu from Selenia.
 
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Thanks buddy! Paraflu is an ethylene glycol based coolant. This comes as a concentrated fluid and hence need to be mixed with water before usage. The proportion is 50:50 (Paraflu : Water) and the concentrate should not be used directly. The recommended change interval is every 2 years or every 60,000 Km which ever is earlier. Also note that you should always use Paraflu only and should not mix it with any other coolants.

Paraflu is recommended by Fiat, Lancia, Maserati and Iveco [thumbsup]
 
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Very useful thread Shynish!

But one doubt , the coolants will be replaced while servicing right? Or should we do it on our own?

Am shocked to know water is a bad coolant. Our Safari was running on water only thanks to TATA'S Authorized service stations, until we rectified it on our own and used those green color coolants.

Am still unable to locate the coolant in my Verna![frustration]
 
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Sometime back I was driving my friend's M800. After half an hour temperature gauge starts moving to higher temperature. I opened the bonnet, the coolant was spilled all over. Poured normal water in coolant container done nearly 200KM after filling and reached home safely.

Next day bought a green colored coolant from a shop and filled.

Moral of story: You can fill normal water. But do it whenever it is absolutely necessary.
 
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But one doubt , the coolants will be replaced while servicing right? Or should we do it on our own?

Am still unable to locate the coolant in my Verna![frustration]

Ideally, the service guys should change coolant periodically. However, what I have seen is (at lease with MSIL service guys) that they just do the top-up of radiator; which is in fact not a good for long run. Hence, it is owners responsibility to remember and completely drain out the radiator and fill in the new coolant as per the advices interval. MSIL guys will do this as a separate work item which they call as flushing of radiator.

Just make a call to the Hyundai toll free customer care numbers: 1-800-11-4645 (Toll Free - Only from MTNL & BSNL numbers)
098-7356-4645 (For all GSM Connections / Landline other than MTNL & BSNL numbers) and ask for the specification for coolant [thumbsup]
 
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Thanks Shynish for your help. I have to check out the condition of my coolant soon in my Verna. I have never checked it till now but the temperature is only normal till now.

So now one doubt again , will the engine temperature rise considerably if the coolant gets used up fully?
 
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Sometime back I was driving my friend's M800. After half an hour temperature gauge starts moving to higher temperature. I opened the bonnet, the coolant was spilled all over. Poured normal water in coolant container done nearly 200KM after filling and reached home safely.

Next day bought a green colored coolant from a shop and filled.

Moral of story: You can fill normal water. But do it whenever it is absolutely necessary.
Over heating happens because various reasons out of which clogged piple line or problems with water pump are the primary suspects. You can always use normal water in radiator. But be informed that it can harm your engine. However as you said, if it is absolutely necessary and there is no other way around, we have to go for it!

So now one doubt again , will the engine temperature rise considerably if the coolant gets used up fully?
When there is an abnormal reduction in coolant is there, you will see a rise in engine temperature. However, you will never get into a stage where the coolant is completely used up; unless there is some leak in the supply line. Since almost all modern cars come with a reservoir for coolant, your radiator will always be toped up. During the normal services, the reservoir is filled up to the indicated MAX level. Check out your coolant type and drain it completely as per the prescribed service interval. If you have not flushed your radiator for a long time, it is a nice idea to do so, as this will help you to remove any clogged particles from the supply line.
 
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When there is a fault in cooling system , the temp goes up . Just stop car if you notice it.

there is some life time for each variety (let name them as variety) of coolant. green one have the least .
change according to age and milage


Mixing proportion should be followed exactly(Not to the decimal point though).


You need to flush old coolant and pour in new mix . You 'll have a drain cork at the pipe connection the radiator and engine part .


Procedure
Start up the engine

Run for few min

drain the old coolant

pour in fresh water (un salted) , if you are afraid use distill water for this too

keep poring for few min , say 2 to 3 min with some interval after some 10 15 sec

after that stand idle for few min , for these water to drain ,


close the drain cork

pour up new coolant mixed with distill water.

that it , new cooling liquid added.
 
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