Cooling system Flush

[beetlejuice]

Originally Posted by drover

I was hoping I could use the bypass line, which is the hose next to the thermostat but its very small ID would take a week................... If I can get hold of an old thermostat, pull the guts out and just swap it with the good thermostat then I can just plug into the header tank pipe with a hose, open radiator drain plug and give it a full flush, easy peasey and top up the engine the same way .............. about 80K km for me to source one for the next coolant change........

I did try to use air at the bypass with the other hose off the engine to push the coolant out but just blew bubbles.............

That's what may try, should have kept my old housing when I changed the thermostat a couple of years ago. You know the old, ha I'll not need that again and in the bin it goes.

[Treebreakerbob]

Originally Posted by 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

As I need to do mine this method interests me, so I am going to assume the bottom or return line under the header tank enters the system after the thermostat and will flush out the block plus if I pressurise a container containing new coolant I could potentially, after reconnecting the hoses and closing the drain valve, then opening the bleed on top of the thermostat, refill the system? Or does it refill quick enough just filling the over flow bottle

Bob

[drover]

I took the header tank hose off from the hose junction as I had fears the plastic bit on the header tank might break.....

I drained mine into a container so I could see how much I got out, supposed to hold 11.5 lts, drained from radiator I got about 4.5lts, about another 6ish out of the engine by the time it started to clear ............. mine was actually just cloudy not muck so it hasn't had town water added at any time......

Once did a service on my Cruiser at work many years ago, used the tank water, a few weeks later I saw my coolant was like mud, I then found out as the tank was low and big winds expected they filled it with town water so it didn't move............ Lots of Crows around that morning.

I had a 20lt drum which I had fitted a tyre valve and a 12mm hose from the tap fitting which you could fill with coolant, keep it at 10psi and it would push the coolant out, used it to refill a Solar HWS, hoped it would work on the by pass hose but the 3mm by pass opening was just too restrictive.

[OLMATE]

Originally Posted by Treebreakerbob

As I need to do mine this method interests me, so I am going to assume the bottom or return line under the header tank enters the system after the thermostat and will flush out the block plus if I pressurise a container containing new coolant I could potentially, after reconnecting the hoses and closing the drain valve, then opening the bleed on top of the thermostat, refill the system? Or does it refill quick enough just filling the over flow bottle

Bob

Yeah, as it enters the Block and Radiator via bottom hose the 24mm OD / roughly 17mm ID hose from the expansion tank fills the system quicker than you think,just leave the radiator cap off to allow all of the air to escape, doesn't take very long for coolant to start coming through the small bypass hose, then I just had it on the first click till the Thermostat opened.
Like I said,I went this way as it was clean, fuss free and I didn't need to make or go out and buy anything to do the job,

[Treebreakerbob]

Originally Posted by drover

I took the header tank hose off from the hose junction as I had fears the plastic bit on the header tank might break.....

I drained mine into a container so I could see how much I got out, supposed to hold 11.5 lts, drained from radiator I got about 4.5lts, about another 6ish out of the engine by the time it started to clear ............. mine was actually just cloudy not muck so it hasn't had town water added at any time......

Once did a service on my Cruiser at work many years ago, used the tank water, a few weeks later I saw my coolant was like mud, I then found out as the tank was low and big winds expected they filled it with town water so it didn't move............ Lots of Crows around that morning.

I had a 20lt drum which I had fitted a tyre valve and a 12mm hose from the tap fitting which you could fill with coolant, keep it at 10psi and it would push the coolant out, used it to refill a Solar HWS, hoped it would work on the by pass hose but the 3mm by pass opening was just too restrictive.

Bugger!

[Treebreakerbob]

Originally Posted by OLMATE

Yeah, as it enters the Block and Radiator via bottom hose the 24mm OD / roughly 17mm ID hose from the expansion tank fills the system quicker than you think,just leave the radiator cap off to allow all of the air to escape, doesn't take very long for coolant to start coming through the small bypass hose, then I just had it on the first click till the Thermostat opened.
Like I said,I went this way as it was clean, fuss free and I didn't need to make or go out and buy anything to do the job,

As I haven’t even looked at doing this yet you will have to pardon my ignorance. “The first click “ presume you mean 1,000 rpm

Your method certainly sounds like the best “kiss” way

Bob

[drover]

I have often wondered just how much coolant is removed when workshops do a coolant change, have always thought not always the lot.... most vehicles I have had to remove the thermostat and bottom hose so I can flush the thing properly...........

Once had a rubber bung with a bit of copper pipe in it which I could connect a hose to and flush the whole system, remove thermostat jam bung in the hole and drop bottom hose, simple but messy, back in the iron block days I just tipped a tin of soluble oil in and topped up with tank water, engine galleries just as clean at 200K km as when new.........