Do I need to or should I chemical flush the cooling system?

[dom14]

Hey Guys,

I just found out there's a smudge of rust under the radiator cap of my RB30 after repeated flushes of the block last year by spraying water into the block via the thermostat hole & while having the engine block flush bolt out(it's on the other side).
I'm not too happy about this 'cos that much rust coming into the radiator from the block, does look bad to me. I used enough anti corrosion coolant with distilled water, so I'm guessing this is not new rust, rather the old rust that's still stuck inside the bottom coolant passages of the engine block.

My question is,

Should I use a coolant flush chemical bottle and try to flush the rust out of the block by breaking it down?
Or is it a bad idea as such chemicals can stuff up the head gasket, water pump, etc 'cos they are way too harsh on old internals parts like head gasket, water pump, etc?

I'm not too fussed about some rust staying in the engine block, but seeing in under the radiator cap, indicates a problem that needs attention, doesn't it?!!
Engine isn't overheating at all. As a matter of fact it's been running "too cool"(never goes above 80 degrees celsius, which I'm about to try to fix by putting in a brand new thermostat).

Coolant looks nice and green. But, I'm putting new anti corrosive coolant & distilled water.
But, before that I would like to sort out this internal rust issue, or need some thumbs up from guys out there if I'm to leave it alone and not worry about it too much.

Any suggestions, tips would be great.

Thanx

P.S. Radiator was taken out of the engine bay and reverse flushed on bench just over a year ago. So, I'm pretty sure it's not the radiator.

I PH tested the coolant & it's 7.5-8 range, so it's definitely not acidic, but rather lightly alkaline, which means it can't be from bad coolant. I also tested the coolant with multimeter(Positive inside the coolant in radiator and negative on earth) and it doesn't show any voltage.

[dom14]

What about using dishwashing machine detergent?!!
It's not as harsh as commerical radiator flush chemicals, is it?

[Turtle_au]

Did you flush out your heater core as well?
It's a good idea to turn the heater on at least once a month to get fresh coolant and inhibitor in the core.

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[garett]

on an old system it could cause leaks. seen the dishwasher stuff used but make sure you flush it very well after and i mean very well.
not sure they work better than a gentle hose in it while it idles. but other ppl might of had better success

[Touses]

What about using dishwashing machine detergent?!!
It's not as harsh as commerical radiator flush chemicals, is it?

Dishwasher cleaner, not detergent. Seems to work ok, was suggested to me by radiator repairer. Empty system, refill with water and cleaner, drive for a week, empty,flush well and refill with coolant.

[dom14]

Did you flush out your heater core as well?
It's a good idea to turn the heater on at least once a month to get fresh coolant and inhibitor in the core.

Sent from my SM-T355Y using Tapatalk

I don't think I did that.
Can the heater core harbour that much rust in it and slowly let it go towards to the radiator?
This time I'll be flushing the heater core as well.

[dom14]

on an old system it could cause leaks. seen the dishwasher stuff used but make sure you flush it very well after and i mean very well.
not sure they work better than a gentle hose in it while it idles. but other ppl might of had better success

My anxiety with using any kinda chemicals is the possibility of them causing head gasket, water pump, etc issues soon after the flush or sometime later. That's why I've been avoiding chemical flushes. But, mine obviously has a bad collection of rust sludge from previous bad maintenance. I've been worried about using chemicals 'cos once I used radiator flush on a Ford Falcon and the head gasket blew up within half an hour, which might have been or might not have been as a result of the flush. Perhaps I didn't burp the radiator properly & caused the head to overheat.

[dom14]

on an old system it could cause leaks. seen the dishwasher stuff used but make sure you flush it very well after and i mean very well.
not sure they work better than a gentle hose in it while it idles. but other ppl might of had better success

It' definitely has some stubborn rust sludge at the bottom of the coolant galleries in the block.
Last time I even reverse flushed the block with the block water flush hole open(just under the exhaust on RB30).
So, I expected the rust to be gone for good, which obviously is NOT the case, by the looks of it now.

[BigRAWesty]

The way I look at this is you have rust.
At some point it's going to break threw and cause you grief.
If you are will to tackle it head in and do it at a time that's convenient to you then chem flush.

Or you take the risk of it possibly blowing out somewhere.. maybe middle of Simpson desert??

I'd personally take it to a professional radiator shop.
Get them to chemical flush the lot, they catch what comes out so saves your driveway and lawns lol.
Get them to pressure test after and report back.

If any issues arise then tackle them.
You may get lucky and have caught the issue early and it's no risk at all..

[dom14]

The way I look at this is you have rust.
At some point it's going to break threw and cause you grief.
If you are will to tackle it head in and do it at a time that's convenient to you then chem flush.

Or you take the risk of it possibly blowing out somewhere.. maybe middle of Simpson desert??

I'd personally take it to a professional radiator shop.
Get them to chemical flush the lot, they catch what comes out so saves your driveway and lawns lol.
Get them to pressure test after and report back.

If any issues arise then tackle them.
You may get lucky and have caught the issue early and it's no risk at all..

I'm fifty fifty divided now whether to chemical flush or not. I prefer the rust sludge from the engine block to come out of the coolant system for good. But, the anxiety of partially damaging the head gasket, water pump etc have prevented me from doing it so far.
I'm OK with it, if the head gasket, water pump etc gives way soon after the chemical flush, so I can fix it.
I'm more worried about their slow death and going kaput in the middle of nowhere. A bit of anxiety driven over thinking I guess.
Somebody told me to get the chemical flush and be done with it.
Perhaps that's what I should do, instead of thinking and overthinking. :)

BTW, whatever comes out, won't mess up the driveway or the lawn. :)

Thanx mate.

[threedogs]

does the coke a cola flush still work or is it too aggressive
on modern motors??

[dom14]

does the coke a cola flush still work or is it too aggressive
on modern motors??

You're not joking, are you? :)

[threedogs]

No I think its an old farmers fix, Ive never
done it but have heard of it being done.
like use an egg or pepper to fix a leak

[dom14]

No I think its an old farmers fix, Ive never
done it but have heard of it being done.
like use an egg or pepper to fix a leak

Yeah, I think it could work since coca cola is mildly acidic.
It would be a good idea to empty the coca cola bottle(s) into a bucket first & let all the fizzy air go first, otherwise
the bubbles inside the coolant system might cause big problems.

[PeeBee]

Coca Cola contains phosphoric acid in very low concentration. Phos Acid neutralises mild steel rust, converting it to an inert oxide. I have never heard of using this treatment for a radiator/motor flush. It won't activate the rust, but it won't release it either. I don't know how effective it would be though once the metal gets re-wetted. We used Phos acid when I was in the mines to neutralise rust before base coating in the acid plant, but that was at much higher concentrations that in a can of coke! I would be a little wary of this treatment, but not being a chemical engineer, i am happy to be corrected. The other thing of concern is the dissolved CO2 in the drink, as this can also be converted to carbonic acid if heated under pressure, so a good flush is in order - know this from steam boiler maintenance and condensate return systems - big problems for boilers.