Flushing coolant system

Tesla · 19 Feb 2011 at 10:01

Hi all,

As per a recent thread I have the front end of my brothers Almera off at the moment (cross member replacement). Before filling with new coolant should I flush through the coolant system to clean out any deposits? If so what's the best procedure. Or, is this not recommended on a 10 year old car. Radiator looks in perfect condition.

Any other maintenance jobs I should consider before I put it all back together?

(I'm getting the AC system leak tested as the AC isn't working but I need to put the condenser and radiator back on for this).

Defcon5 · 19 Feb 2011 at 13:18

What condition is the coolant in? Is it regulrly changed?

sigma · 19 Feb 2011 at 13:34

I normally just flush using a hosepipe and flush the rad separately out too.

Not sure on the specific method for your car, bleed points etc; do you have a workshop manual for it?

Tesla · 20 Feb 2011 at 06:57

Defcon5 said:
What condition is the coolant in? Is it regulrly changed?

Car was bought last year and AFAIK no history of a change. The coolant was the exact colour of wee.

ShakenNstirred · 20 Feb 2011 at 07:13

flush with a hose flowing in the opposite direction to the flow when the engines running

Avionyx · 20 Feb 2011 at 08:06

As above, connect to the hose positioned physically lowest in the engine bay, usually at the bottom of the rad, and use a hosepipe on a medium pressure setting flushing in the opposite direction to the normal flow I.E "backward"

You do it on the lowest hose as thats more likely to be where all the crud collects and then you've got the highest pressure at the dirtiest bit - if you get me?

Some people like to do it Backward-forward-backward. But I'm not sure how much benefit it would have.

Tesla · 20 Feb 2011 at 09:27

Does this not push the "crud" back into the coolant system if it builds at the lowest point?

Scania · 20 Feb 2011 at 11:22

I use the hose method, I always use hot water too.

Fuzz · 20 Feb 2011 at 11:39

You aught to remove the thermostat to do this more effectively.

Scania · 20 Feb 2011 at 11:48

Scubascorpion said:
You aught to remove the thermostat to do this more effectively.

I think this is why I use hot.... ( I say I think as it sounds right & have always used hot but can't recall why I was told to do so

)

Lethagized · 20 Feb 2011 at 11:49

Unless it's thick rusty coloured water or the HG has gone, it won't really need flushing. By the sounds of it with the water being urine coloured, it doesn't need it.

If you really want to flush it though, fill it up with normal water and run the engine up to temp for a bit to open the thermostat, run it for 10 mins, drain off then refill with a 50/50 mix.
Doing it this way, you can stand back with a cuppa and test to see if the fans are working too.

Fuzz · 20 Feb 2011 at 12:05

R420LA6X2/4MNA said:
I think this is why I use hot.... ( I say I think as it sounds right & have always used hot but can't recall why I was told to do so )

Hot tap water is only going to be around 60 degrees C. The thermostat doesn't open until at least 78

bledd · 20 Feb 2011 at 12:34

RobRX-7 said:
Unless it's thick rusty coloured water or the HG has gone, it won't really need flushing. By the sounds of it with the water being urine coloured, it doesn't need it.

If you really want to flush it though, fill it up with normal water and run the engine up to temp for a bit to open the thermostat, run it for 10 mins, drain off then refill with a 50/50 mix.
Doing it this way, you can stand back with a cuppa and test to see if the fans are working too.

This is what I did

Scania · 20 Feb 2011 at 12:50

Scubascorpion said:
Hot tap water is only going to be around 60 degrees C. The thermostat doesn't open until at least 78

Yes, good point,in that case, I guess I use hot as the hose stays nice & warm then!

Tesla · 20 Feb 2011 at 19:07

Thanks for all the replies. I am going to just fill it with tap water, run it for 10 minutes, drain and then fill with anti-freeze.