Cooling system flush recommendations please

[Mr Ree]

Hi all,
Im going to be installing a bigger radiator in my JZA80 tomorrow and I want to go back to using Toyota Red coolant (from current green) so thought that I would run a flush through to get rid of any crap inside the motor/heater before putting the new core in.

Im going to drain out as much cooalnt as possible then refill with water and run up to temp, a few times over until there is no trace of anti freeze left in the system then run the flush.

I was wondering if anybody here (preferably in the trade) that has had experience with a particularly good brand to use?

Thanks

[Dell'Orto]

A lot of my trade guys use Prestone flush

[Mr Revhead]

To help shift stuff, undo a heater hose and ram the garden hose up it and turn it on (not full bore) leave it till it runs clear. Then put the hose on where the heater hose came off to reverse the flow. repeat until it all runs clear.

[solitaire]

To help shift stuff, undo a heater hose and ram the garden hose up it and turn it on (not full bore) leave it till it runs clear. Then put the hose on where the heater hose came off to reverse the flow. repeat until it all runs clear.

Nice tip, will remember that

[Mr Ree]

I almost bought one of those kits that installs a garden hose fitting into the heater line, for that exact purpose Mr Revhead, but then figured I only need to flush it once every few years anyway so will just use the method you described.

I have read far too many threads where people have not flushed the heater core properly when switching back to Toyota Red Coolant so I want to ensure I get 100% of the green stuff out first.

Cheers Dellorto, I will buy some prestone stuff today

[Sick Puppy]

I have read far too many threads where people have not flushed the heater core properly when switching back to Toyota Red Coolant so I want to ensure I get 100% of the green stuff out first.

For those that haven't read any of the threads, what happens?

[iOnic]

I use Abro stuff in a yellow bottle + jamming a fresh water hose up the heater hose ports and engine block coolant bypasses

Edit: This

[crispy'86]

In my experience at work if you don't properly flush the cooling system of the green and add the LLC, vice versa or put the wrong antifreeze in, the coolant turns to a dark brown/black colour, both inhibitors must react with each other and create almost a thin sludge (kind of like having an oily texture) over time that can block heater and radiator cores if left unnoticed. This is of course a worst case scenario, creating all sorts of overheating and flow troubles further down the line.

[strx7]

remove radiator
remove thermostat, put thermo housing back on.
attach garden hose to radiator hose which goes to thermo housing.
turn on said garden hose.
fire up motor and run for a while on garden hose & water pump circulation with heater turned on (it aint going to heat anything but it will flow fresh water)
keep hose going & motor running until water coming out other radiator hose is fully clear and free of particles of any kind.

[Mr Ree]

In my experience at work if you don't properly flush the cooling system of the green and add the LLC, vice versa or put the wrong antifreeze in, the coolant turns to a dark brown/black colour, both inhibitors must react with each other and create almost a thin sludge (kind of like having an oily texture) over time that can block heater and radiator cores if left unnoticed. This is of course a worst case scenario, creating all sorts of overheating and flow troubles further down the line.

Quoted for truth.

It only needs a very small amount of green left in the bottom corner of a heater core to make the flush and refill pointless, not to mention a waste of money.

I have personally used a garden hose on a heater hose for hours one day, until it ran completely clear. Left it for a couple of hours and came back to it, turned the hose on and what do you know...more green shit.

It can take alot longer than you would expect to get all 100% of it out.

[Mr Revhead]

Which is why reversing the flow a few times helps loosen and remove it all plus accumulated crap. I have restored a few heaters to working condition by that method. beware though that in a marginal cooling system it could start a few leaks. But if so it was $&#$% to begin with.

[Mr Ree]

Yes indeed I will be giving it plenty of reverse flushing too

Hopefully my cooling system doesnt fall into the "marginal" section either hehe.

I bought some new OEM radiator hoses, 2 weeks ago, off Mark, to replace at the same time as the radiator so hopefully there arent any weak links.

I also plan to buy all new OEM heater/coolant bypass hoses once I have a few dollars in hand again, Ill just be extremely carefull when removing them from the heater lines going though the firewall as the last thing I need is to crack one of those by accident, as I really dont want to deal with pulling my dash out to replace a $&#$% heater pipe lol

[Mr Revhead]

Where possible I remove the hose from the engine end rather than wrestle with a possible Brittle plastic firewall bulkhead pipe.

[Bling]

If you're replacing them, just cut them off the heater core pipes, then slice off whats left. Some hoses become one with the pipe they are attached to, so cutting them off gets around having to yank them off.

[Mr Revhead]

Some hoses become one with the pipe they are attached to

^&*%@!!!!



Sorry, flash backs

[sergei]

Be careful around the heater core hoses, as the heater core is copper and the outlets bend very easily.

To fully drain the engine you will need to take out the drain bolt on the block (on 4A it is next to oil pressure switch, on 3S is next to Hose from Hell).

I also suggest tacking out thermostat and putting hose up there. Make sure you never over pressurise the system (the mains pressure is very high and will burst the hoses and radiator) by having radiator cap off and radiator drain out when you shoving hose in various holes.

[crispy'86]

Yip seen few instances where someone removes the hose off the heater core and makes a abominable mess of the once nice and round pipe. So yeah do as everyone states remove thermostat and run with heater on full, maybe few engine revs i.e 2000rpm or so, obviously not right round to the limiter.
Had to do this when i first got my '86 as the system was *@%%( rusty, took me 2 hours worth of flushing and backflushing, getting it up to temp for a while, removed thermostat and flushed. And yip my heater core started to leak a year later but was satisfied my cooling system wouldn't have an epic fail on a run down to twizel

[Quint]

hoses become one with the pipe they are attached to.

*mutter mutter mutter*

[Mr Ree]

Be careful around the heater core hoses, as the heater core is copper and the outlets bend very easily.

To fully drain the engine you will need to take out the drain bolt on the block (on 4A it is next to oil pressure switch, on 3S is next to Hose from Hell).

I also suggest tacking out thermostat and putting hose up there. Make sure you never over pressurise the system (the mains pressure is very high and will burst the hoses and radiator) by having radiator cap off and radiator drain out when you shoving hose in various holes.

I could be wrong but I thought the series 2 A80 got an aluminium heater core, although I wouldnt be surprised if the series 1 was copper.

I seem to recall they did the same thing with the radiator so its pretty likely.

[gt4dude]

whatever u do, dont do that powder shit called Bars that they have in supercheap auto, its Nasty!!! Blocks shit hard!! I still got little grains of it floating around its hard to get out