[bhp1]

Is it necessary to change coolant at specified service interval, what can be the harm if coolant is not changed at specified time?

If I skip regular change at mentioned interval, how long will the old coolant suffice?
Also, does old coolant freeze in cold climate conditions?

[drpullockaran]

Originally Posted by aka_iitd

Coolant will never boil
I meant if you put normal tap water it will boil without any additives

It is pressure that decides at what temperature water or any fluid boils. This is 8th class funda. Increased pressure increases the boiling point of water. If water is boiling in your cars radiator then you need to check the coolant conduits for leaks. The additives that we add, erroneously referred to as coolant will also boil at the temperatures the car coolant passages reaches; and it does not, only because of pressure build up in a sealed system. The water in the pressure cooker of our house boils at 120 to 125 degrees centigrade and not at 100 degrees centigrade. The concentrate we add is to help lubricity of the pump and also to prevent freezing at really cold temperatures. In tropical climates like in Kerala its addition is only for lubrication and prevention of rust.

[drpullockaran]

Originally Posted by bhp1

Is it necessary to change coolant at specified service interval, what can be the harm if coolant is not changed at specified time?

If I skip regular change at mentioned interval, how long will the old coolant suffice?
Also, does old coolant freeze in cold climate conditions?

The only problem in tropical climates that you are liable to face is reduced anti rust properties of the concentrate. It is adviced to change coolant, power steering fluids and brake fluid atleast once a year to prevent rust of conduits.

I change everysingle fluid of my cars once a year even if its not warranted in the manual. If not for the inept service engineers at TATA even my Junkindica would have been purring along like my GTX does. I thank my lucky stars that the GTX has not yet recquired to go to the TATA service centers for anything even though I bought it in July 2003.

[bhp1]

Thanks DrpullocKaran, that was informative.
Does this also mean that one can change oils/fluids from outside ie. non OEM ? As OE stuff breaks the bank bigtime!
Any other side effects except rust?


Edit: I just took the last few words from nick!

[greenhorn]

who is Karan

@ doc, i thought the coolant was a premixed water + additives. so what we get as coolant is just the additive bit , and should water be added to bring it to the correct concentration?

[Sankar]

Originally Posted by aka_iitd

I think water will boil out and you can hear water boiling after driving for 5 to 10 mins. Once i need to put water as my coolant was drained out due to leakage and experienced the above.

Like stated by others the water doesn't boil as quick in a pressurised system. In your case it boiled because you refilled the water coz the coolant had drained due to a leak. A leak - which drops the pressure in the system.

Originally Posted by greenhorn

who is Karan

@ doc, i thought the coolant was a premixed water + additives. so what we get as coolant is just the additive bit , and should water be added to bring it to the correct concentration?

You get both types - coolant concentrate as well as premixed with water. It will be mentioned in the bottle. In most cases it's wise to follow what's written on the bottle, like how many parts of coolant per liter of water etc.

[Takumi-san]

do not mix different types of coolant ; thats what it says on the bottle in capitals. And I think those guys who make it should know what they are talking about. If you want to jeopardise your water pump , and other metal parts by making them a catalyst to a chemical reaction go ahead. If you have mixed them then perform a radiator flush (even one with water is fine) and pour in coolant and water in the recommended ratio. For top ups use only water (preferably battery water) and flush the system every couple of years.