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Flushing And Replacing Coolant

webng

By webng,
in General Maintenance

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webng Experienced

webng

Posted
Posted

Hi,

I'm a bit of a DIY noob. This weekend I am going to flush and replace the coolant in the radiator. From what I've researched, it just a matter of undoing the bolt below the rad, undo the top cap, drain, fill up with tap water and run engine at max heat for a minute or so, repeat until tap water flushes clear. Redo nut/bolt and fill with coolant mixture. Run a bit and top up if needed.

Have I missed anything? Do i need to 'bleed' the thing?

Thanks!

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RB30-POWER Mentor

RB30-POWER

Posted
Posted

to flush it properly you need to either remove the block drain plug under exhuast manifold, or its usually easier to remove the thermostat, or else the thermostat traps old water in block still.

you will need to bleed it when you refill it, at the bleeder nipples.

also be careful about using the drain tap, usually if the radiator is old, they just snap off and you need an entire radiator, its far easier and safer IMHO to remove the radiator lower hose. that way there is no suprises.

webng Experienced

webng

Posted
  • Author
Posted (edited)
to flush it properly you need to either remove the block drain plug under exhuast manifold, or its usually easier to remove the thermostat, or else the thermostat traps old water in block still.

you will need to bleed it when you refill it, at the bleeder nipples.

also be careful about using the drain tap, usually if the radiator is old, they just snap off and you need an entire radiator, its far easier and safer IMHO to remove the radiator lower hose. that way there is no suprises.

Thanks, after reading that i'm thinking it's not really that simple :)

1. Where's the exhaust manifold? Or Thermostat?

2. Where are the Bleeder Nips?

3. What's a Drain Tap?

4. Where's the Radiator Hose?

Sorry!

Edited by webng
Godzilla32 Veteran

Godzilla32

Posted
Posted

This is how i flush cooling systems at work:

If you have a drain plug that is accessible on the radiator use it to drain the radiator, otherwise drop the bottom hose off the radiator.

Make sure your heater is switched to full hot, you may need the ignition on if you have climate control. (This flushes the heater core too)

Pull one end off the most accessible heater hoses and put a garden hose down it tightly (remove the nozzle and just poke the hose in)

Turn the hose on fully and watch the old coolant flow from the radiator drain hole and the spot where you removed the heater hose.

Let the water run until it runs clear. Remove the garden hose

Put the radiator drain back in and leave the heater hose off.

If your engine has a air bleed screw in the cooling system/intake mannifold loosen it now.

Start filling the system with coolant keeping a close eye on the heater hose and pipe where it was removed from.

DO NOT REFIT IT UNTIL COOLANT FLOWS FROM IT. WATER IS NOT COOLANT

This way you push out all the air in the system and all the excess water (otherwise you wont fit much coolant in)

Leaving the heater hose off helps with air pockets in the system in a BIG way

Once it starts to flow the color of the coolant put the hose back on and continue filling the system with the correct percentage of coolant concentrate.

When it won't take anymore coolant start the engine and get it circulating by holding the revs up slightly.

While you do this you should be able to add more coolant/water.

Leave the radiator cap off until there are no more bubbles coming up through the coolant and both radiator hoses are nice and hot.

If you have an air bleed screw do it up once coolant flows steadily from it.

This means that the thermostat has opened, it can take quite awhile so be patient

Once both hoses are hot you can refit the cap and take it for a drive (keep and eye on the temp guage)

Don't turn off the heater tap until you feel hot air coming out of the vents. (cold air means you have most likely an air pocket in the system)

Have fun :)

Godzilla32 Veteran

Godzilla32

Posted
Posted
Thanks, after reading that i'm thinking it's not really that simple :)

1. Where's the exhaust manifold? Or Thermostat?

2. Where are the Bleeder Nips?

3. What's a Drain Tap?

4. Where's the Radiator Hose?

Sorry!

1. If you dont know where your exhaust mannifold is maybe you shouldnt be doing this ;) Thermostat in a housing at the engine side of either top or bottom radiator hoses.

2. Bleeder nipple will be on your intake mannifold and will say do not open when hot next to it on a little gold sticker.

3. Drain tap will be on the bottom of your radiator, if you have a drain tap that is.

4. Radiator hoses run from the tanks of the radiator to engine.

I think either invest in a workshop manual if you can find one or take it to a garage. If your in Brisbane i can do it for you.

Deren :)

webng Experienced

webng

Posted
  • Author
Posted
1. If you dont know where your exhaust mannifold is maybe you shouldnt be doing this ;) Thermostat in a housing at the engine side of either top or bottom radiator hoses.

2. Bleeder nipple will be on your intake mannifold and will say do not open when hot next to it on a little gold sticker.

3. Drain tap will be on the bottom of your radiator, if you have a drain tap that is.

4. Radiator hoses run from the tanks of the radiator to engine.

I think either invest in a workshop manual if you can find one or take it to a garage. If your in Brisbane i can do it for you.

Deren :)

lol, maybe i shouldn't, but it's worth a try anyways. I don't mind getting my hands dirty and learning bit by bit.

Really appreciate the info, thanks for that. I'll have a go this weekend. :)

Godzilla32 Veteran

Godzilla32

Posted
Posted

Your welcome, the only thing you can do wrong is drive it with an air pocket in it and over heat it...just run it with the cap off and make sure all the air is out before you drive it and then watch you gauge. :) If the gauge rises while you drive it and it wont read normally (ie too hot) pull over and crack the cap to the first click to release the air then if theres no coolant coming out carefully remove it the rest of the way and top it up then it should be sweet.

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