Cooling system Flush

[beetlejuice]

Hey folks,

Done the dreaded 4 coolant hose project and ready to do a full flush before adding coolant. Reading the forum last night it appears there is no way of getting all the coolant out as you're only dropping what's in the radiator.

If that's the case, I'm thinking there's no point running a flush additive through the system as it will take ages to get all of it out, is that the correct assumption? I know you can't leave any of that stuff in the system it's caustic. The last time I personally did a coolant flush was on an old Holden Brougham, back then it was just disconnect the bottom hose, shove the garden hose up it, take out the thermostat, a run it till the water ran clear.

Going to cost a fortune doing flushes with just demineralised water or am I overthinking this? Was a long day yesterday, still looking for 8mm sockets that dropped off the hose clip tool (surprise not the 10mm )

Thanks for any tips

[Grippy]

Where about in Australia are you mate? Some of our water is better than others, like ours here in Adelaide is quite hard and full of minerals, not what you want in the cooking system. However, when I did the radiator and flushed it on my old 4.7 Grand, I just pumped the hose in there, easiest way and at least it's got some flow. You could always do that, then chase it down with a bottle of demineralised water.

[beetlejuice]

I'm in Vic mate where the water is not too bad.

[drover]

First off don't use tap water, even no matter how good its supposed to be it always has some minerals in it which at the very least can leave a scale build up in the galleries which slowly chokes the system, flakes can block radiator cores at the worst corrosion as the coolant and metals react to the minerals................ Deminerlised water is the good stuff, I have always used filtered tank water.....

The Grand is a pain to flush, drained from radiator drain tap with cap off header tank, I ended up lifting the thermostat and pulling the engine hose off, flushing the old coolant out with the hose (rainwater from poly tank) after flushing the rest of the bits, filled it up with tank water , went for blat with windows open and heater on full bore, then drained it all again, then tried to funnel fill the engine via the removed thermostat, gave up and topped it with water, filled the hoses up with straight coolant, tipped the rest in the header tank and topped up with water so I got the 50/50 mix, then went for a run, bit of gurgling/noise at first as I backed out of shed then all good........... so long as you get a 50/50 mix in the system its good, hence why I tipped the balance of the concentrate in then added the water..... the drain tap at bottom of radiator is one of the best I have come across, I actually use it without the fear it will pull out of the bottom ....

[beetlejuice]

Thanks Drover, I thought it was going to be a pain in the arse.

I was going to lift the thermostat but running out of time today, so I plan to arrange a mobile flush mob to come out tomorrow and do it at work. I've added 5 ltrs of coolant which I know is going to go to waste, but at least it's got something in it for the next 24hrs.

Thanks for posting,

Cheers

[OLMATE]

Undo the radiator drain plug, remove the clamp off the top hose ( Thermostat end) so the hose can be easily removed and replaced, take the lower hose off the overflow expansion tank, I got a (small garden hose nozzle that fits perfectly in the above hose) used the original hose clamp to hold it in place, turn the tap on moderately ( not flat stick as depending on your water supply pressure could cause leaks and blow heater core) and watch how much shit comes out of the top hose when taken off to allow initial flush, as that's when the majority of gunk will be expelled from the system, done this a couple of times with the top hose off as I didn't want any of the shit going back into the system between replacing those hoses and running it up to temp. In the end water from last dump was as clean as that going in. I filled up system via overflow bottle, 6 lt 8yr 500,000km Nulon Red concentrate, system self bleeds via small bypass hose coming from near Thermostat to top of overflow bottle, so as you are filling it up, any air is being expelled.one tip, have the nose of the Jeep pointing up an incline as it allows the air to make its way to the top so much easier, eliminating any nasty air pockets, only had to crack the Thermostat bleeder a couple of times as there was bugger all air.
While I was doing the above flushes I had the overflow bottle full of hot water with couple of anti scale tablets soaking, come up like a newy
Honestly the Jeep was a hell of alot easier than what I read others had to go through

[beetlejuice]

Thanks Olmate, very much appreciated for the indepth how to.

I was just a little concerned about leaving the thermostat in and running cold water from the tap through the system, because it will never open, therefore not a lot of flow. But if you've been successful this way well why not give it a crack.

Cheers