REALLY Dirty Cooling System - Flushing Advice, Please

[Citroënbender]

I’m stuck on this with the Benz job.

Three flushes (first with Repco blue flush, same stuff as Nulon, Penrite) - and it’s still coming out substantially “muddy”. Is there anything reliable that won’t destroy a 40-year-old alloy head or what’s left of its gasket?

I’ve read comments by Americans about using “two pounds of citric acid powder” but (a.) that might be vernacular, not literal and (b.) it might be hard to obtain here in the form they’re familiar with.

[burnz]

bicarb of soda, 500g to 10 litre's of water.

[Franco Cozzo]

I just used 10L of white vinegar mixed with the remainder of distilled water then drive the car around.

Worked an absolute treat on a 3.8L Ecotec but she's all cast iron, might be a bit too dodgy for this German crapola.

[smoo]

Fleetguard do a product called restore.
Should be able to get it at Cummins or Kenworth or Multispares.
My go to for oil contamination in cooling systems.

[Citroënbender]

Restore Plus sounds like the right spec, need to get some details for how much to add, how long to leave it. $85 delivered for a gallon bottle.

https://truckparts.com.au/genuine-fl...m-cleaner.html

Have read cautionary notes about bicarbonate vs aluminium engine parts, hard to say how much is the internet hype and how much is cause for concern.

Watched the ChrisFix video, my third flush still looked like his first.

[smoo]

Originally Posted by Citroënbender

Restore Plus sounds like the right spec, need to get some details for how much to add, how long to leave it. $85 delivered for a gallon bottle.

https://truckparts.com.au/genuine-fl...m-cleaner.html

Have read cautionary notes about bicarbonate vs aluminium engine parts, hard to say how much is the internet hype and how much is cause for concern.

Watched the ChrisFix video, my third flush still looked like his first.

Brochure and bottle label should cover it.
I have had good results from a normal 30min road tests.
Scale/rust may need running longer and higher concentration perhaps.

https://www.cumminsfiltration.com/si...20Brochure.pdf

[MrEL]

I normally drop the coolant , put a cup of washing powder in , fill it with water and drive it for a couple of hundred kms and half a dozen heat cycles.
Then drop it out and flush it.

[fordomatic]

I recently had the same issue with a car. I bought some commercial mechanics only acid like you bought above. In the end I lost count at 15 flushes. It took me over two weeks of flushing but it eventually cleared.

[arm79]

I had a similar thing with the POS Ghia. Probably still had the original coolant in it that had completely broken down into brown sludge and solidified in places. Was like dirty bore water or something from the edge of the Murray River.

Flush after flush did nothing. I avoided anything acidic for fear of eating through something that shouldn't. Read a post about someone who used this you-beaut cleans anything flush. It ate through his custom alloy radiator.

Probably not the answer you want, but 90% solved it be replacing the radiator. There still is a dirty film across the insides of the metal parts and hoses, but it doesn't seem to contaminate the water and it stays rather clean. With the required dose of green coolant you cant tell there is any brown bits in there.

[PG2]

Originally Posted by arm79

I had a similar thing with the POS Ghia. Probably still had the original coolant in it that had completely broken down into brown sludge and solidified in places. Was like dirty bore water or something from the edge of the Murray River.

Flush after flush did nothing. I avoided anything acidic for fear of eating through something that shouldn't. Read a post about someone who used this you-beaut cleans anything flush. It ate through his custom alloy radiator.

Probably not the answer you want, but 90% solved it be replacing the radiator. There still is a dirty film across the insides of the metal parts and hoses, but it doesn't seem to contaminate the water and it stays rather clean. With the required dose of green coolant you cant tell there is any brown bits in there.

Agreed. Replace the radiator. By the time you buy 10 cans of whatever you could buy a new radiator.

Also, if the sludge is that bad you may find that that radiator is blocked up anyway.

[Citroënbender]

The radiator is a fairly recent replacement, at least by mileage, and was north of $600 (supply cost) when done. I’d tolerate brown coolant ahead of replacing it just to eliminate discolouring.

Fordo’s comments about perseverance plus chemicals are probably on the mark for my situation, just not what I wanted to hear. Everyone likes a silver bullet.

[PG2]

Originally Posted by Citroënbender

The radiator is a fairly recent replacement, at least by mileage, and was north of $600 (supply cost) when done. I’d tolerate brown coolant ahead of replacing it just to eliminate discolouring.

Fordo’s comments about perseverance plus chemicals are probably on the mark for my situation, just not what I wanted to hear. Everyone likes a silver bullet.

Why are you flushing it? Is it overheating or is it that you just like seeing green fluid?

You could still flush it until it is clear and still find that the radiator is blocked.

[Citroënbender]

I like to see fresh-coloured coolant, because of OCD.

It seems to not be overheating, although I haven’t checked thoroughly and weather is mild. I believe a damaged and mis-fitted lower hose caused a lot of coolant loss and the previous owners just took to topping up with plain water before driving it. So it had no protective chemicals and frequently also abundant air to feed oxidisation.

[Franco Cozzo]

Changing coolant is overrated, old mans car went 420,000km+ on its original coolant, then it spat its clutch which unfortunately was unrelated

[MattSAU2XR8]

Assuming that it is cooling OK I wonder if you could just stick to green coolant and change it every three to six months until it clears up?

Corrosion inhibitor in the coolant should stop it getting any worse, and I suspect will gradually dissolve all the crud which is basically going to be metal oxide. And if it (crud) gets dissolved slowly then it is less likely to block up the radiator since it will be in smaller particles, or hopefully actually in solution.

I always worry about flushing compounds because (a) then could potentially chew away at gaskets, and (b) they can cause large chunks to break loose and block up the radiator.

I'm pretty sure either acid or alkali will break up the scale. Certainly acid will because its what metalworkers use to 'pickle' the stain off welds. And alkali because a mate once flushed his radiator with caustic soda.

[Citroënbender]

This is a photo from yesterday. Zooming in a little, I can see where the flushing agent has affected the “layering” of deposits. It just hasn’t worked very hard.

The appeal of that Fleetguard agent is in its chelating properties, if then purged fully and replaced with coolant it should leave residual iron as a loose black sediment with no affinity to any surface. While repeated changes of coolant would definitely stop further corrosion and expel suspended matter it won’t shift much of deposits firmly bonded to a surface.

[PG2]

Originally Posted by Citroënbender

This is a photo from yesterday. Zooming in a little, I can see where the flushing agent has affected the “layering” of deposits. It just hasn’t worked very hard.

image

The appeal of that Fleetguard agent is in its chelating properties, if then purged fully and replaced with coolant it should leave residual iron as a loose black sediment with no affinity to any surface. While repeated changes of coolant would definitely stop further corrosion and expel suspended matter it won’t shift much of deposits firmly bonded to a surface.

The radiator core seems to have bits of rust stuck in there.

[roKWiz]

Just a thought. The problem I see with using truck core cleaners is it might work to well and loosen a lot more rust scale, causing the thinner car type fin cores to block.
The sheer size of a truck radiator allows easy rodding of the individual bores after these cleaner loosens the crud.

[PooDog]

Originally Posted by Citroënbender

This is a photo from yesterday. Zooming in a little, I can see where the flushing agent has affected the “layering” of deposits. It just hasn’t worked very hard.

image

The appeal of that Fleetguard agent is in its chelating properties, if then purged fully and replaced with coolant it should leave residual iron as a loose black sediment with no affinity to any surface. While repeated changes of coolant would definitely stop further corrosion and expel suspended matter it won’t shift much of deposits firmly bonded to a surface.

The only way you will get all the bits of rust out ( in the picture ) is to take it to the radiator specialist and have the top and bottom tanks removed and cleaned properly .....if your really fussy about it ( unless your a handy solderer

[Citroënbender]

Yes, that’s about $120 from memory to un-crimp, flush and re-crimp.

Here’s the way the header tank end of the core looks after putting the hose through it - a subtle improvement:

[ivorya]

Any weak acid will work. ie/ citric, vinegar(Acetic).

As someone mentioned, put it in and drive around. It will take the heat and some time to remove all. May need to give it a couple of goes.

[Citroënbender]

Bought a new 13PSI cap last week, hoping this one will get the pressure (and temperature) up slightly. Should be beneficial to the flushing process, maybe also some of the thermostatically switched aspects of motor control.

Citric acid from the local pool supply shop, that's what i used to clean my intakes on my Merc.

Cannot see why they wouldnt make a radiator core sparkle also ?

If you have ever had the B series milk shake between Transmission and Radiator then i have found several flushes with laundry powder to be the best bet...

[Citroënbender]

Apparently citric’s a chelating acid, so might well be part of the Fleetguard brew.

The little particles observed by PG2 and others, are actually quite small and if the cleaner does its thing, should not block the core tubes.

Have read that ferric citrate is a recognised mineral supplement for hoomans, so maybe I can bottle/sell my flush water when it’s done?

[Citroënbender]

Have sold the owner on taking it for a three-hour “Sunday Drive” while the Restore Plus does its thing. So if it breaks down anywhere between Freeman’s Waterhole and here - not my problem.

[smoo]

Originally Posted by roKWiz

Just a thought. The problem I see with using truck core cleaners is it might work to well and loosen a lot more rust scale, causing the thinner car type fin cores to block.
The sheer size of a truck radiator allows easy rodding of the individual bores after these cleaner loosens the crud.

One can dilute it to suit, but check the modern non serviceable truck alloy radiators like in Freightliner Mack and anything Euro. Size of the tubes is around the same as an LV.

[smoo]

Originally Posted by Citroënbender

Have sold the owner on taking it for a three-hour “Sunday Drive” while the Restore Plus does its thing. So if it breaks down anywhere between Freeman’s Waterhole and here - not my problem.

I get the feeling you’ve invested so much time and energy into this car you’re becoming attached to it.

[Citroënbender]

I’m not convinced. Will pay the seats (comfort), space/visibility of the cabin and evident rustproofing to many structural sections.

For a three hour drive, I’d prefer the Territory. Similar comfort plus mod cons.

[Citroënbender]

Thumbnails, as I’ve not resized the images. Unfortunately they are night-time (flash) photographs so the colouring is not consistent with earlier pictures. Credit to @smoo for the product recommendation.

I used a shade over one litre of Restore Plus with plain water, the car was driven at freeway speeds for about three hours. Flushing agent remained in the system four and a half hours. I pressure flushed it with the hose (my mains pressure is quite strong) at least three times. Car now has a shandy of Types A and B coolant, they’re both ethylene glycol based so will mix fine.

It’s possible to now see where resting ferrous particles from the block have reacted with the radiator core to erode the aluminium. I’d say it has compromised radiator life and gives me ideas (not good ones) about condition of the head/gasket interface. That said, there’s no significant early buildup of system pressure and the new cap is sealing as hoped.