DIY coolant replace + flush

  • Seeing HTML codes in old articles? Just reply "help" and we'll fix the article immediately.
    We're making improvments to the site right now so bear with us! - May 21 2020

Izso

Boooooossst
Helmet Clan
Moderator

Izso

Boooooossst
Helmet Clan
Moderator
Mar 28, 2004
14,900
6,270
5,213
KL


Radiators to a car is the skin to a human being. Without it, the body cannot release heat generated internally via the sweat glands. Similarly the radiator transfers the heat from the engine block to the coolant and out to the atmosphere through the radiator.

It's also said that for every degree lost is a horse-power gained. So it only makes sense that you change the coolant in the system to ensure maximum cooling efficiency (assuming your radiator fan and thermostat is in good working order).





Now, ideally you should catch the coolant fluid when you release it however I did a environmentally bad thing and released the fluids to the ground. Don't be like me. Should there be any tree huggers around your area you can be guaranteed to be harassed by those blokes if you don't dispose the coolant properly.

So anyway - start with a cool car. A hot car / coolant / everything is not fun to play with.




Look at the bottom of your radiator and locate the release valve.




In my case it looks like this (sorry about the blur picture). The white knob is the coolant release valve. To get to the knob is not an easy task for people with stubby fingers like mine. So I used a long nose plier to turn the valve open.




Next up take out the reserve/overflow tank and clean it. 99% of the time it'll have sand or sediment in it. Rinse it with water or give it a scrub down, just make it clean.




Due to the simplicity of the K3VE engine design, I can access my thermostat very easily. Two size 10 bolts and it's out.




Now I happen to know mine is faulty (the spring hardened) so I replaced it with a new one. For those folks who don't know what the thermostat is for - it ensures your engine is heated up to the optimum temperature for the engine oil to flow at its optimum state, so don't ever throw it away! Too cold and your engine won't get lubricated properly and that's a big no-no. Too hot and you'll melt something. According to my thermostat labeling, the Myvi's ideal temperature is 80 degrees Celsius. That's when the thermostat opens and lets the coolant flow from the radiator into the block.

Now some thermostats are held in with a gasket or some sealant or both. If yours is not spoilt, I don't suggest you take it out. If yours is like mine, no sealant and just two nuts, no harm taking it out. It'll make the flush easier.

I pulled out my thermostat and hose for easy flushing later. 2 x size 10 nuts and one clamp to remove everything.




By now the coolant would have completely flowed out of your radiator. If not - you have forgotten to remove the radiator cap. :banghead:

Reminder - Never open the cap if the engine is hot. Even the slightest bit hot, you'll have some pressure build up and that's nasty when you open it. So always open the radiator cap when cold.




Close the release valve at the bottom of the radiator first. Then stick your garden hose down the radiator opening and let the water run. It'll come out of the engine block where your thermostat was and let it run until the water is clear. Then open the release valve and release all the tap water.

For those who can't remove their thermostats easily, don't close the release valve at the buttom and let the water run, fire up your engine and rev at 3k rpm until the radiator fan turns on. This indicates the thermostat has opened and water is flowing into the engine block and out of the release valve. Please note that the thermostat won't open for a good 15 to 20 minutes so be patient.




This next step is controversial. Some folks say tap water is sufficient to fill the radiator because the minerals and what not in the water will be burnt off at optimum engine temperature. I believe in using distilled water because distilled water contains no minerals to be left behind in the cooling system (which ultimately results in a blockage). In my car I personally don't think 80 degrees is going to burn off anything and more often than not leave deposits in the system.

So I flush using distilled water until my hearts content. RM5 for one large 5L bottle. I used up 1 bottle.




Ensure the water coming out of the engine block is clear and not coloured. One you're done flushing, re-install the thermostat, the thermostat housing and the hose.




Ensure your release valve at the bottom of your radiator is closed. Next up pour in 1 bottle of coolant (1L pure coolant) and fill up the rest with distilled water. Press the hoses to squeeze out any air bubbles that might be there.

Start up the engine and wait for the thermostat to open (the radiator fan will activate) and pour in more distilled water as the coolant level will drop. The thermostat will open up after 20 to 30 minutes of idling (you don't need to rev), keep pouring the distilled water if you see the coolant level drop.




By now the engine is already hot. The coolant will start bubbling and steaming so be careful not to touch it. It's freaking hot! Let it bubble and "burp" itself for a good 30 to 45 minutes, in-between which the thermostat should open a few times. Keep filling up until the coolant level stops going down and stops bubbling (you don't see much froth on top anymore as seen in the picture). Once complete turn off your engine and do any last minute topping up of distilled water and replace the radiator cap.

Replace the reserve tank (or overflow tank - whatever you call it) and fill it with a mixture of coolant and distilled water to the "maximum" level. Don't overfill this.

And you're done!


Time spent doing this DIY : Over 2 hours
Water wasted doing this DIY : Over 5 gallons
Explaining to your wife why you used perfectly good drinking water in the car : Priceless

:biggrin:
 

Attachments

  • Like
Reactions: minibeany

Kevin Lee

1,500 RPM
Senior Member

Kevin Lee

1,500 RPM
Senior Member
Jan 26, 2009
1,677
1,085
1,713
Kampar, Perak
great stuff, but u spelt coolant and gallon incorrectly!!

haha were u inspired to write about the radiator after looking at the forged racing radiator babes

ur a diy guru for sure
 

Edward_Lee

From Facebook

Edward_Lee

From Facebook
Aug 16, 2010
17
3
503
www.facebook.com
Very good step to step explanation on how to flush our radiator but there's some facts need to be correct. As u mention abit for every deg celcius u take away = gained in horsepower. Actually in correct term horsepower = amount of heat produce. So in other words correct way to explain this shud be optimal operating temperature give best horsepower out of an engine. Just to share ..... no hard feeling.
 

EvolutionZ

5,000 RPM
Helmet Clan
Senior Member

EvolutionZ

5,000 RPM
Helmet Clan
Senior Member
Aug 3, 2007
5,028
1,448
1,713
thanks for the sharing.....i just about to send for flushing.
 

drexchan

2,000 RPM
Senior Member

drexchan

2,000 RPM
Senior Member
Nov 23, 2004
2,908
100
3,163
Bukit Jalil
drexchan.fotopic.net
It's also said that for every degree lost is a horse-power gained.
I think this is more applicable to intake air temperature. Colder engine coolant doesn't translate to better performance as you've described later.

By now the engine is already hot. The coolant will start bubbling and steaming so be careful not to touch it. It's freaking hot! Let it bubble and "burp" itself for a good 30 to 45 minutes, in-between which the thermostat should open a few times.
I hope that you didn't actually let the engine idle for that long without the radiator being capped back. There's a purpose to have the radiator cap (other than allowing your to flush and fill the radiator).

It's to sustain a higher pressure than atmosphere inside the cooling system. Like a pressure cooker, this will increase the boiling point, thus preventing bubble build-up inside the cooling system at the working temperature of the thermostat. (Steam bubble in its gaseous state is not a good medium for heat exchanging).

The reason why it takes so long for the coolant to stop bubbling is that - it may never stop if you keep the radiator cap away.
 

D7zul

2,000 RPM
Senior Member

D7zul

2,000 RPM
Senior Member
Feb 24, 2011
2,697
849
713
Shah Alam
I think this is more applicable to intake air temperature. Colder engine coolant doesn't translate to better performance as you've described later.


I hope that you didn't actually let the engine idle for that long without the radiator being capped back. There's a purpose to have the radiator cap (other than allowing your to flush and fill the radiator).

It's to sustain a higher pressure than atmosphere inside the cooling system. Like a pressure cooker, this will increase the boiling point, thus preventing bubble build-up inside the cooling system at the working temperature of the thermostat. (Steam bubble in its gaseous state is not a good medium for heat exchanging).

The reason why it takes so long for the coolant to stop bubbling is that - it may never stop if you keep the radiator cap away.
about the air bubbles..

u need to fill the cooling system with 100% water + coolant.. if got bubbles, ur engine will overheat.. coz air is hotter than water + coolant..

i saw lots of mechanic doing this..

and yes, i will stop bubbling after some time.. i've done this a few times already..

FYI, bubbles come from below.. not from the top (radiator cap) :wink:
 

bera

500 RPM
Senior Member

bera

500 RPM
Senior Member
Oct 27, 2007
824
229
1,543
yup...it is better to remove all the air bubble...there is a device for that called bubble remover i think...trapped air can cause air lock...and will lead to kong water pump...

like if you got air in you arteries (we seldom hear it as angin ahmar)...sure cause stroke...after that either die or paralyzed... :shot:
 

amrancharger

500 RPM
Senior Member

amrancharger

500 RPM
Senior Member
Jul 19, 2006
779
96
1,528
good info there bro izso...thumbs up for u.

i use the red coolant for all my cars including the peroduas.

some one ought to teach me wats the difference between the green and red coolant available on the shelf in most shops... :confused:
 

Izso

Boooooossst
Helmet Clan
Moderator

Izso

Boooooossst
Helmet Clan
Moderator
Mar 28, 2004
14,900
6,270
5,213
KL
Bro, my radiator rusty inside. What should I do?
Suggest you flush until the rust is clear.


I think this is more applicable to intake air temperature. Colder engine coolant doesn't translate to better performance as you've described later.
Yeah I know. But it was just something that sounded right. Hehe.


I hope that you didn't actually let the engine idle for that long without the radiator being capped back. There's a purpose to have the radiator cap (other than allowing your to flush and fill the radiator).

It's to sustain a higher pressure than atmosphere inside the cooling system. Like a pressure cooker, this will increase the boiling point, thus preventing bubble build-up inside the cooling system at the working temperature of the thermostat. (Steam bubble in its gaseous state is not a good medium for heat exchanging).

The reason why it takes so long for the coolant to stop bubbling is that - it may never stop if you keep the radiator cap away.
Yes, I mentioned 20 minutes or so for the thermostat to open a few times. I do that to purposely burp out all the air bubbles if possible.

---------- Post added at 10:45 PM ---------- 6 hour anti-bump limit - Previous post was at 10:43 PM ----------

great stuff, but u spelt coolant and gallon incorrectly!!

haha were u inspired to write about the radiator after looking at the forged racing radiator babes

ur a diy guru for sure
Got it.. thanks.

Guru? No la. I'm only a 'descendant' of the original DIYs sifus. LOL
 

drexchan

2,000 RPM
Senior Member

drexchan

2,000 RPM
Senior Member
Nov 23, 2004
2,908
100
3,163
Bukit Jalil
drexchan.fotopic.net
Yes, I mentioned 20 minutes or so for the thermostat to open a few times. I do that to purposely burp out all the air bubbles if possible.
I understand the motive as we've discussed today in the shop. But I forgotten to mention to you that, there are hot spots in the water channels especially those casting marks with sharp edges.

The thermostat is only activated by the coolant temperature around it, but not sensitive to the temperature in those hot spots between the pump and the thermostat (basically the entire block and head). The thermostat does open at the rated temperature, but there are hotter spots especially in the water jacket around the cylinders liners.

Depending on the chemical content of the coolant (boiling point), engine speed (heat-up rate) and A/F ratio (exhaust temperature), these hot spots can cause heat shock and the resulting temperature may exceed the boiling point of the coolant. Internal micro-boiling must be prevented and the easiest way is by suppressing thermal expansion.

Thermodynamically, leaving the cap opened allows an undesired thermal expansion (I bet that you saw the coolant expanding and overflowing from the radiator mouth as the engine heats up), and micro-boiling can occur at the hot spots. Micro-boiling is what created the fizzy situation after the bubbles (trapped air) have been removed entirely.

I am not saying that your method is wrong but it was unnecessary. I must also remind you that the situation didn't get worse because you've used ethylene glycol coolant, and the small 1.3 engine wasn't generating enough heat to cause a bizarre boiling. If you have done that with tap water on your or my Wira 1.5, you may get a home-made little Yellow Stone.

So my point is, top the water level after the first thermostat opening, and cap it back. Then fill the reserve tank to the mark and call it a day.

---------- Post added at 12:32 AM ---------- 6 hour anti-bump limit - Previous post was at 12:26 AM ----------

bera and D7zul,
Thanks for sharing your experience and knowledge.
Point taken but not accepted. ;]

---------- Post added at 12:51 AM ---------- 6 hour anti-bump limit - Previous post was at 12:32 AM ----------

Reminder - Never open the cap if the engine is hot. Even the slightest bit hot, you'll have some pressure build up and that's nasty when you open it. So always open the radiator cap when cold.
Before it's open, the hot coolant is under higher pressure but not boiling. The moment the cap is opened, the pressure is released and the coolant is allowed to expand. However, it's not the thermal expansion that's causing the high pressure steam jet and coolant burst. It's the sudden pressure drop (due to expansion) that has reduced the boiling point of the coolant below its temperature at the time. This subsequently boils the coolant abruptly in the entire cooling system, and water is turned to steam at 1700 times of expansion rate (no joke). Therefore, even the slightest amount of the coolant got boiled up, the bursting result can still be phenomenal.
 
Last edited:

Izso

Boooooossst
Helmet Clan
Moderator

Izso

Boooooossst
Helmet Clan
Moderator
Mar 28, 2004
14,900
6,270
5,213
KL
Drex - Ok thanks for the tips. 1 time thermostat open and close shop. Got it.


good info there bro izso...thumbs up for u.

i use the red coolant for all my cars including the peroduas.

some one ought to teach me wats the difference between the green and red coolant available on the shelf in most shops... :confused:
I don't think there's a difference anymore. Most coolants are ethylene glycol based which means they are aluminium friendly coolant. Old coolants were made with substances meant for steel radiators and weren't compatible with aluminium radiators. But since 90% of the new cars out there use aluminium radiators as stock, it only makes sense to stop producing the old coolant since the ethylene glycol based coolants are compatible anyway.

But I could be wrong. I used Toyota (red colour) and Nissan (green colour) coolants in my car and the default one was red in colour. All seems to work for me.



would u guys recommend using 100% coolant instead of topping it up with water??
There's a brand out there that's either pre-mixed or 100% pure coolant. Not cheap! Something like RM140 for 4L bottle. You can opt for that but personally I think that's overkill. Pouring in 5 bottles of Toyota coolant is not a good idea as these mixes were meant to be diluted with water. It might be acidic on its own.
 

amrancharger

500 RPM
Senior Member

amrancharger

500 RPM
Senior Member
Jul 19, 2006
779
96
1,528
I don't think there's a difference anymore. Most coolants are ethylene glycol based which means they are aluminium friendly coolant. Old coolants were made with substances meant for steel radiators and weren't compatible with aluminium radiators. But since 90% of the new cars out there use aluminium radiators as stock, it only makes sense to stop producing the old coolant since the ethylene glycol based coolants are compatible anyway.

But I could be wrong. I used Toyota (red colour) and Nissan (green colour) coolants in my car and the default one was red in colour. All seems to work for me.
thanks for the info...
i find the green coolant to be much cheaper then the so called LLC(long life coolant).
however i find dat at the label...the red color coolant(LLC) is also recommend to be changed annually...
 

D7zul

2,000 RPM
Senior Member

D7zul

2,000 RPM
Senior Member
Feb 24, 2011
2,697
849
713
Shah Alam
So my point is, top the water level after the first thermostat opening, and cap it back. Then fill the reserve tank to the mark and call it a day.
i've seen a few mechanic doing this also.. i just thought they were lazy.. hehe..

but i think after a few days, we need to refill the reserve tank, right?