How To Flush And Re-Fill Radiator Coolant

The Don · October 2, 2014

Use a reputed brand. I don't think there are big differences between known brands like BG, BP, Caltex, Wurth etc. Premix coolant is usually better than coolant you mix with water.

Also there is no difference between coolant used for petrol engines from diesel engines.

Edited October 2, 2014 by The Don

Ruslan · March 2, 2015

Sorry to Bring up an Old thread, Thought of sharing my findings on coolant types for Japs, my car came with factory filled Pink coolant (Toyota). checked with the Agent and the premixed coolant is 8000/- per can (4Ltr, i know it's a bloody rip off). mind you this factory speced coolant was advised to changed on after 160,000Km but to have a peace of mind thought of replacing it. looked for alternatives for this (Engine spec required to fill it with coolant with "silicate, nitrite, amine and borate free" with "hybrid organic acid technology" - as per findings, silicates are bad for water pump it seems) and found out that Valvoloine Zerex Asian Vehicle Premixed coolant at Unit#d Mot#rs for 1650/-. which is matching the factory spec.

http://www.valvoline.com/products/brands/zerex/antifreeze/105

Edited March 2, 2015 by Ruslan

asrock · March 2, 2015

How often do you need to flush and refill the coolant?

The Don · March 2, 2015

On 3/2/2015 at 8:12 AM, asrock said:
How often do you need to flush and refill the coolant?

I recon about every 3-5 years will be enough as long as the car was always run with coolant (this depends on vehicle usage. Ironically you need to flush cars which are rarely used more rather than cars which are in use regularly).

If you have switched over recently, I'd suggest at least do it anually for about 2 years so as you don't have issues with blockages as the flush could dislodge sludge which might get trapped, so will need to be cleaned out by replacing coolant again. This time there is no need to flush, just replace coolant.

asrock · March 2, 2015

Thanks for the explanation Don, I recently got my car, yom 2007 according to the odo it havent run much. Coolant colour is still pinkish. anyway I think its better to flush the system soon.

Splat · March 2, 2015

Something I like to share - I once repaired my radiator and had to bleed the air out of the cooling system. The plastic bleeder screw (Originally came) was too old and the white plastic faded to brown and brittle. " it snapped " with " screw head out and shaft inside" but I managed to get the screw shaft out. I went to Panchikawatta and I bought a plastic bleeder screw spending 150/=. The screw fitted I bleed the cooling system and I was happy. But not for long the screw leaked again. So I went to a local machinist and got a brass screw lathed for 250/=. It was a supper performance up grade I would say.

Also to prevent overnighting the bleeder screw (plastic or brass) use a tippex or a thin felt marker and mark a line on the screw and body. and tighten it only up to the mark DO NOT OVER-TIGHTEN. "prevention is better than cure"

Splat · March 2, 2015

Thanks Schiffer, brilliant job. Keep up the good work .....

The Don · March 2, 2015

On 3/2/2015 at 12:25 PM, asrock said:
Thanks for the explanation Don, I recently got my car, yom 2007 according to the odo it havent run much. Coolant colour is still pinkish. anyway I think its better to flush the system soon.

Before coolants became popular, I used to flush the cooling system with fresh water and the radiator never had signs of sludge or rust.

A small thing to point out. Coolant is extremely poisonous. If you let it fall to the ground nothing will grow on that bit of land, and you must avoid it getting mixed with waterways or drains. Carefully collect the coolant in containers and dispose of safely and wear gloves and keep out of the reach of children.

This is one of the reasons why I don't really like using coolant, and prefer just water (distilled is better) as I don't poison everything around me when I need to flush and work on the cooling system. This obviously will be different if the coolants were more enviromentally friendly, and it can be in our climate because I think its the anti freeze element which is most harmful.

Splat · March 3, 2015

As time pass even distilled water alone can contract iron particles. so its better to use distilled water with a radiator anti-rust & water pump lube additive. eg- http://www.amazon.com/Motor-Gunk-C1012-Radiator-Anti-Rust/dp/B000ABG9T0

The Don · March 3, 2015

On 3/3/2015 at 5:33 AM, Splat said:
As time pass even distilled water alone can contract iron particles. so its better to use distilled water with a radiator anti-rust & water pump lube additive. eg- http://www.amazon.com/Motor-Gunk-C1012-Radiator-Anti-Rust/dp/B000ABG9T0

Usually Gunk products are good, but you are looking at only one side of the equation. Adding additives into engines can have unintended consequences due to long term chemical reactions break downs and bonding. This is why it is generally advised to stay away from additives for long term use (rather than solving a particular issue) as they could become deposits, suffer chemical breakdown etc.

A lot of additive manufacturers have not done tests on long term viability of their products.

For example some synthetic engine oils caused havoc in engines due to chemical breakdown at high ambient temperatures as experienced in the tropics causing sludge deposits requiring engine overhauls in SL.

I say this. Cars are not meant to run forever and over time some parts will decay and need to be replaced. We should be careful as to what we put in them beyond manufacturer reccomended items as the long term issues might outweigh the benefits.

Splat · March 3, 2015

I agree thanks for the input. and yes, cars are not meant to run forever. God is infinite and man is finite. Thank you once again

Edited March 3, 2015 by Splat

sahan84 · March 6, 2015

Hi all,

I have Alto vehicle and 8000Kms done after last coolant replacement.What is the recommended Kms that I need to replace coolant?

asrock · March 6, 2015

refer this thread: http://forum.autolanka.com/topic/15374-how-to-flush-and-re-fill-radiator-coolant/page-2

there are some explanations at the end

sahan84 · March 6, 2015

Thanks for the reply,

And In my car it shows coolant level 1-1.5 cm below the optimum level (minimum level). so what I can do for this without going for a new purchase?

I do not travel daily.

Nishan.dj · March 6, 2015

On 3/6/2015 at 7:18 AM, sahan84 said:
Thanks for the reply,
And In my car it shows coolant level 1-1.5 cm below the optimum level (minimum level). so what I can do for this without going for a new purchase?

I do not travel daily.

Is your engine getting heated than normal? If not refill the coolant. Else you need to check what causes it to heat more. It is normal to see the coolant is reducing a bit with time.

sahan84 · March 6, 2015

I never seen Engine heated above the mid level (heat level). Looking at the coolant bottle level only i'm asking.Thank for the reply.

Nishan.dj · March 6, 2015

On 3/6/2015 at 7:32 AM, sahan84 said:
I never seen Engine heated above the mid level (heat level). Looking at the coolant bottle level only i'm asking.Thank for the reply.

as per i know, this is normal. you can refill it. use the one you had used before. its good that you open the bonnet sometimes.

Davy · March 6, 2015

On 3/6/2015 at 6:57 AM, sahan84 said:
Hi all,
I have Alto vehicle and 8000Kms done after last coolant replacement.What is the recommended Kms that I need to replace coolant?

Coolant replacement interval varies depending on the type and brand of coolant used. Generally, you can run for over 30,000kms (or about 2 years, whichever comes first)on a batch of coolant.

1cm of coolant loss is nothing to worry about. Just top up your coolant and monitor the level to see if it keeps dropping. If it does, there's probably a leak.

The Don · March 6, 2015

Topics merged

Splat · May 3, 2015

Has anyone had any water pump issues after flushing the cooling system with any chemical flush ?????? :popkorn:

Edited May 23, 2015 by Splat

Pubsamare · August 20, 2017

Sorry for bringing up an old thread guys. My car was made in 1995 and has been using water for last few months due to some ongoing repairs. Now that the repairs are over, planning to do a rad flush and put coolant. There is a lot of rust in the water at the moment. My worry is after using the flush will there be leakage once the rust goes away. Please advise guys, is it a good or a bad idea to use rad flush in an old vehicle?

Edited August 20, 2017 by Pubsamare

Davy · August 20, 2017

On 8/20/2017 at 5:37 AM, Pubsamare said:

Sorry for bringing up an old thread guys. My car was made in 1995 and has been using water for last few months due to some ongoing repairs. Now that the repairs are over, planning to do a rad flush and put coolant. There is a lot of rust in the water at the moment. My worry is after using the flush will there be leakage once the rust goes away. Please advise guys, is it a good or a bad idea to use rad flush in an old vehicle?

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If there is excessive rust, you have the option of getting your radiator cleaned. This involves taking the radiator off the car, separating the top and bottom tanks from the core and thoroughly cleaning everything. This will remove most of the rust. After the repair, you can use water for a couple of days to rinse out the remaining rust in the system. You can then drain out the water and use coolant.

If you think opening up the radiator and cleaning isn't necessary, use a flushing liquid and do a thorough flush. It's unlikely that leaks would develop after a flush.

Pubsamare · August 20, 2017

On 8/20/2017 at 1:44 PM, Davy said:

If there is excessive rust, you have the option of getting your radiator cleaned. This involves taking the radiator off the car, separating the top and bottom tanks from the core and thoroughly cleaning everything. This will remove most of the rust. After the repair, you can use water for a couple of days to rinse out the remaining rust in the system. You can then drain out the water and use coolant.

If you think opening up the radiator and cleaning isn't necessary, use a flushing liquid and do a thorough flush. It's unlikely that leaks would develop after a flush.

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Thanks Davy. My radiator is less than 2 years old. So guess flushing would be enough then.