How Do I Flush Out Coolant?

[ZILR-34]

Hey guys

Okay long story short I toke off the head to get reco'd and the time it was away the water gallery’s got rusty on the block so when I bolted it up I had rust residue in my coolant.

My question is how do I go about cleaning it/flushing it out???

cheers

bill

[No Crust Racing]

Disconnect both hoses from the radiator and use a hose to flush water back and forth through the block, using both radiator hoses. Keep at it til she runs clear then let it sit for a while draining out the water so you're not diluting your coolant mix too much when it goes back in. I can't remember if the thermostat blocks the water flow extensively in the RB25 as it's been ages since I had one. Just see how you go. If you're going from the thermostat side and the water ain't coming out the other pipe then you may need to remove the thermostat also. Good chance to do the radiator at the same time. For a quick confirmation, give a local radiator/coolant specialist a buzz and make sure you're happy with the direction you're going to take. It's your car in the end.

Good luck

[ZILR-34]

once its comes clear. would the rust residue come back?

[No Crust Racing]

So long as you put the right mix of coolant back in and there's no leaks you should be fine. If any of the internal galleries or the radiator etc have suffered badly from rust then you may have some rust still in the system but the coolant should keep it in check. If in a few weeks after refilling with coolant the fluid goes brown again you may need to flush it all fully again.

Do it the first time and see how you go.

[ZILR-34]

is there anything i can buy to add to the water it get rid of the rust? like C.L.R or any acids?

[No Crust Racing]

Good question, I'm not 100% on that one so best to cool a radiator joint and ask them. Giving a workshop a call is no big deal and they're usually more than happy to assist.

[RB30-POWER]

plenty of additives you can add to the cooling system, run it for half and hour then dump it, flush it and refill with new coolant. just have a look at the local parts place. repco, bursons etc.

there is a drain under the turbo you can undo, but it is a bitch of a spot.

my advise, remove thermostat housing and thermostat when you want to flush it with the hose, otherwise the thermostat will block the water from draining out.

other option is to pop off a heater hose at back of engine.

whatever is easiest really.

[White GTS-T]

Just make sure you 'reverse flush' the system. i.e. flush it in the opposite direction the water normally flows. And make sure you reverse flush the radiator, block and heater core separately to avoid cross contamination. Personally i think a flush gun is a must.

[ZILR-34]

i found this on the net. what u guys think of this product?

http://www.evapo-rust.com.au/Cooling%20System%20Flush.htm