Rusty cooling system...

Discussion in 'Technical' started by noel0leon, Sep 25, 2017.

  1. noel0leon

    noel0leon Member

    Hi team,

    So car the manual conversion is complete and the car is currently at a shop getting a 100k service plus water deletes done.

    However, the mechanic showed me that the cooling system pipes have a coating of orange/yellow rust inside them. Before I started the conversion I did a full flush and clean of the cooling system. I got a whole bunch of brown out and then ended up with nice clear fluid. Filled with distilled water and antifreeze. but seems like there is a whole bunch more.

    I'm getting new plastic hoses and possibly a new radiator but I want to know if there is a way to clean out the rust in the hard pipes in the motor.

    Knowing that our motors are finicky about cooling, I found this procedure that is being used by guys with classic cars:

    They use Oxalic acid, commonly sold as Wood Bleach. And let that sit in the cooling system for a few days (keep lightly using the car) and it's supposed to 'eat and disolve' the rust. Then neutralise, flush and go from there. https://www.jalopyjournal.com/forum/threads/best-way-to-de-rust-cooling-system.943881/

    Is this too aggressive for the VG?

    Anyone else tried to de-rust their cooling systems?
     
  2. QLDZDR

    QLDZDR ID=David

    Oxalic acid is definitely the stuff to use on rust.
    The best rust converters have that, but topical.
    Didn't know it was to used internally.
    I don't think it should be used on rubber/plastics
     
  3. Eggs

    Eggs Member

    Anyone know if it dissolves aluminium?
     
  4. noel0leon

    noel0leon Member

    I read that a little bit isn't too bad. But long term it will eat the anodizing on aluminium. I'm assuming the radiator and heater core are steel?
     
  5. Eggs

    Eggs Member

    Heater cores are generally aluminium for quick heat transfer. I think stock header tanks are plastic
     
  6. geron

    geron National Petroleum Equipm

    Or you could try regular say by-monthly or monthly flushes till it all goes away if only light rust. (This will take some time).
    If scaly rust, keep an eye on the small overflow bottle hose. (disconnect from radiator and blow through it occasionally). If that gets clogged, there will be excess pressure build up which will blow a hose or a radiator side tank if OEM. This could lead to engine overheat if the coolant is dumped and you won't know till it's too late.
    This little hose, does get clogged if there are large rust chunks circulating. It happened to me! Lost an engine, a bottom radiator hose and a radiator side tank, exploded. Then I realised what was going on and the cause of it and most unexpected.
     
    Last edited: Sep 26, 2017
  7. QLDZDR

    QLDZDR ID=David

    Oxalic acid (Phosphoric acid) can't be good for the heater core or the radiator. You would bypass those when doing that flush method, right?

    Geron's post mentioned the overflow bottle and reminds me, I put a magnet on a string in there. The rust stays in the overfow bottle with the magnet.
    Every other month you should disconnect the overflow hose and flush the overflow bottle out with the garden hose. Watch all that stuff clear out.
     
    Last edited: Sep 26, 2017
    geron likes this.
  8. rob260

    rob260 Administrator Staff Member

    Power flush it.
     
  9. geron

    geron National Petroleum Equipm

    The magnet in the overflow bottle is a great idea!! If the water is dirty the overflow bottle gets caked with rust particles on the walls and looks brown. A long time ago, I washed the overflow bottle many times using small pebbles/rocks and shaking vigorously with water. It comes up looking close to new.

    Power flush is great and also discard any hoses with caked scaly rust inside of them. DON'T USE THEM, get new ones and be done with it.

    Also, monitor the rust by looking on the inside of the radiator cap occasionally. If you see rust being caked on it, the rust still persists and time for a flush again sometime down the track.
    There should be no rust inside the radiator cap or radiator filler neck.

    Also, if the cooling system has been abused, it's a good idea to get the radiator rebuilt or replace it with an Aluminium unit (not necessarily a thick radiator) one from eBay is fine. The OEM Radiator will have rust caked inside it and it gets released slowly contaminating new coolant.

    Oh, and while I'm at it, a new fan clutch and fan works a treat to keep those temps down even on a 40° day, no problem.

    Once the cooling system is rectified, it will never be an issue again. 10ys + & no probs with rust.
    The rust occurs b/c people don't use anti boil/anti freeze/anti corrosive additive, a big No, No which also affects the heater core.
     
    Last edited: Sep 27, 2017
  10. ADAMZX

    ADAMZX 2000spec Conversion

    I would suggest maybe trying a what a guy on YouTuber calls a "Super Flush" which requires you to do multiple flushes of the entire cooling system using coolant flush and demineralised water to clean out the cooling system to remove as much rust as possible until the water being flushed out of the cooling system is clear and clean.



    I attempted this same procedure myself minus the thermostat removal and it took me 8 hours to do 3 flushes. I'm confident my cooling system is pretty clean but with only 2 flushes its hard to know and I did not clean my overflow bottle which I will do next time my cooling system gets disassembled.​
     
  11. noel0leon

    noel0leon Member

    Thanks guys. Some good solutions here.

    Once it's back from the shop I'll change all hoses. Do regular flushes and try that magnet idea.
     
  12. QLDZDR

    QLDZDR ID=David

    I know I said that I put a magnet in my overflow bottle. my coolant is green without being cloudy, so I think that is an improvement for anyone.

    Since the overflow bottle is plastic, there isn't any reason to put the magnet inside the coolant overflow bottle, when we can just gaff tape a bunch of magnets to the outside of the coolant overflow. You can even buy a bunch of magnets already built into a belt with velcro fasteners (they make them to wrap around oil filters) and put that on the overflow reservoir.

    Obviously that belt of magnets cannot be wrapped around any other part of the cooling system because if you put it around the radiator hose it would collect metal particles and build up like plaque in an artery and when big enough it will break in a big magnetised lump and damage something in engine.

    [​IMG]
    But you could make some kind of bypass in the main coolant flow that allowed some coolant to move through a removeable container and magnets could be placed around that. (That is a water trap for a compressor, to try and put a picture to the idea) When it fills up, just unscrew and empty it.
     
  13. QLDZDR

    QLDZDR ID=David

    [​IMG]
    This might be something to use during the flush?
     
    noel0leon likes this.
  14. noel0leon

    noel0leon Member

    Where'd you see that man?
     
  15. QLDZDR

    QLDZDR ID=David

    I have to be on another forum because I have a couple of Commodores (owned by parents) that have electrical and mechanical gremlins.
    I was chasing one of many Commodore cooling system issues and saw that. The photo has the company details.

    between the sock and a magnet belt around your overflow reservoir bottle, you'll be clean coolant again in no time.
     
  16. QLDZDR

    QLDZDR ID=David

    [​IMG]This is a product that is supposed to be wrapped around the oil filter. I am suggesting you can make something similar and velcro it around your overflow reservoir
     

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