Coolant flush- clarification

[K.o.N.o.S]

Guys, my car was leaking coolant for sometime and it turned out the issue was with the radiator cap & radiator tank ( the one that connects with the radiator cap). So I replaced the cap and the tank and on the process the garage guy drained my old coolant. He advised not to fill it with new coolant at least for another 3 days because of the newly installed tank. Instead he filled the system with water only. I am planning to add fresh coolant to the car this weekend. My question is should I do a total flush of the coolant system before adding coolant or just add coolant? The mechanic said a total flush would not be required. Appreciate your expert opinion on this. Thanks in advance

[Davy]

Since you had coolant in your radiator before, I assume there is no rust in the system. If this is the case, you don't have to do a flush with a flushing liquid. What I suggest doing is to drain the existing water, run a few cycles of fresh water through the system (to get rid of any debris or rust) and then fill with coolant. 

Here's a DIY for reference. Skip step 2.

 

[K.o.N.o.S]

Thanks for the info Davy. Also may I know the cooling capacity of the system? Is there a proper way to measure besides collecting the draining water from the system? ( demio 2009 YOM) 

[Davy]

  On 3/28/2018 at 10:10 AM, K.o.N.o.S said:

Thanks for the info Davy. Also may I know the cooling capacity of the system? Is there a proper way to measure besides collecting the draining water from the system? ( demio 2009 YOM) 

Expand  

You don't need to measure the amount of coolant because you need to fill the radiator to the brim. After you've filled the radiator, run the car with the AC on for about 10 minutes to bleed out the system (get rid of any air bubbles in the system). As the air goes out, the coolant level will go down a bit. Top up as necessary, secure the cap and fill up the expansion tank to the MAX mark. Keep an eye on the expansion tank coolant level for a couple of days.

If you're asking to determine how much coolant to buy, a 5L can should be sufficient if you are using coolant that's pre-diluted. Others require you to mix coolant and water to a specified ratio.

EDIT:

The US/Canada version of the Owner's Manual says 5.4L. This should be more or less the same for the JDM Demio. 

 

 

Edited March 28, 2018 by Davy
Added more details

[K.o.N.o.S]

Thanks much. I am actually planning to add caltex premixed ( green) coolant so Won't have to add water. Further may I know the reason as to why should I fill the reservoir to the max line? Shouldn't that be between the max & min lines?

[Twin Turbo]

Go to your owner's manual. refer cooling system maintenance.The max line denotes the upper limit  for the coolant to be stored leaving for expansion clearance .

[Davy]

  On 3/28/2018 at 12:15 PM, K.o.N.o.S said:

Thanks much. I am actually planning to add caltex premixed ( green) coolant so Won't have to add water. Further may I know the reason as to why should I fill the reservoir to the max line? Shouldn't that be between the max & min lines?

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Yes, it should be between the min and max marks. This is to allow room for overflow if the system builds up pressure. Since you're filling it for the first time after draining all coolant from the radiator, it's safer to fill it up to the MAX mark because there still might be a few air pockets in the system which will be filled in by the coolant in the reservoir. So the level will drop a little bit anyway. This is why it is important to keep an eye on that level for a couple of days until it settles down.

[K.o.N.o.S]

Thank you for the info