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Block flush at home?

Discussion in 'The Hokey Ass Message Board' started by shooter54, Dec 1, 2010.

  1. shooter54
    Joined: Apr 25, 2006
    Posts: 5,037


    I've been having some repeated issues with my cooling system. I had my radiator cored and rebuilt, etc. because it was clogged and the car would run about 220 all the time and overheat in traffic.

    Since doing that, I've determined that I must have a buildup of rust and sediment in the block because it will do great for a few weeks, running at 180 or lower, then eventually will start to run consistently at 200, then 210, 220, etc. and I'll drain the coolant enough to see that the passages in the radiator are clogged with sediment. I'll drain the coolant, flush the radiator out as best I can using a garden hose/pressure washer(carefully) and It will spit out a lot of debris. Then it's fine for another few weeks until the whole thing happens again.

    I contacted the radiator shop and they recommended that I flush the block to remove the sediment in the rest of the system.

    I would rather not pay them $125-$150 to do this, and I'm sure it can be done at home. They mentioned they use water and air pressure and go in through the thermostat area.

    Has anyone done this? Any tips at all for this process?

    It's a chrysler 383 if that is of any importance.

  2. The price doesn't sound too bad for what you want done, I've seen higher.

    If I was going to do it, I would back flush, as in oppsite direction of normal coolant flow. Don't forget the heater core. In fact, I would run a short hose connecting the two eigine side hose nipples and flush the block and heater core seperate.

    Check your radiator cap to see what psi it is. If it is less that 10, you might want to be careful about how much air pressure you add. Too much could blow out the radiator/heater core.
  3. Prestone sells a flush kit, still should be available in parts stores. It hooks up using the heater hose, how effective it'll be in your case, who knows? I've had them wash out seals on water pumps a couple of times, but worth a shot for little $$ laid out.

  4. Bigchuck
    Joined: Oct 23, 2007
    Posts: 1,087

    from Austin, TX

    I worked at a radiator shop way back in the 70's. We used to do flushes through the thermostat area by removing the thermostat & pulling off the lower radiator hose. The flushing "tool" was simply some tubing that a water and air hose attached to. It had an on/off valve for the water and a squeeze handle for the air blast. The connection to the block was just a big rubber cone that you held into the opening.
    Turn on the water, hit the air, and you had a pressure blast through the block. Worked pretty good on getting all the loose rust and sediment out. It doesn't seem like it would be too hard to make a similar contraption with some plumbing stuff.
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  5. Kyron
    Joined: Dec 28, 2006
    Posts: 116

    from Peoria Az

    I had a 22r motor with the same issues ....... I used a muratic acid/water mixture through just the motor with one of those little giant pumps in a bucket and cycled the water through the bucket.

    It worked great, but thrashed the water pump ;)

    * The heater core was disconected too
  6. Joe Johnston
    Joined: Jun 29, 2008
    Posts: 127

    Joe Johnston
    from Ohio

    Similar to Kyron's method which will work well, but not quite as harsh, is a mixture of washing soda and water. NOT baking soda, but washing soda - sold in large grocery stores in the detgerent area. Mix a strong solution, pour in and drive till hot then drain. Repeat until the water exits clean. Had a very rusty FE which was always overheating and it cured my problem. That car had a copper radiator so I have no knowledge of the soda's effect on an aluminum one.
  7. 32v
    Joined: May 20, 2007
    Posts: 882

    from v.i.

    go to the hardware store you can buy a plastic tube that attaches to a hose and swells up to seal the opening (upper rad hose with thermostat removed) then shoots a small high pressure stream of water. it is used to clean pluggged plumbing drains works great
  8. Oxalic acid, oxalic acid, oxalic acid (AKA wood Bleach)! It will SAFELY remove all the rust and scale from the block, heater core and radiator with out harming ANYthing. Has been used as a heavy duty cooling system flush for decades ("GM Heavy Duty Cooling System Cleaner")...
    Muttley likes this.
  9. shooter54
    Joined: Apr 25, 2006
    Posts: 5,037


    Thanks for the tips guys. I think I'll just do it myself.
  10. newsomtravis
    Joined: Jun 1, 2009
    Posts: 562

    from pville, ca

    hey 345 desoto, where can you get that acid, i`ve noticed it as the active ingredient in most of those store bought flushes, but the never seem to cut it, and i`ve used muriatic, but sometimes it has been hard to the oxalic acid not as harsh?
  11. CutawayAl
    Joined: Aug 3, 2009
    Posts: 2,145

    from MI

    If the block is seriously rusted/corroded/sedimented, nothing will do the job short of removing and disassembling the engine, removing all the plugs, then aggressive cleaning. I have had cases where a block was returned from a thorough alkali hot tank cleaning and still had near concrete like sediment in the water passages. Molton salts cleaning will remove those kinds of deposits, but that gets the casting hotter than I like.
  12. Do Again
    Joined: Mar 22, 2010
    Posts: 26

    Do Again
    from San Diego

    hardware store should carry it. Even ebay sells it.
  13. junk yard kid
    Joined: Nov 11, 2007
    Posts: 2,642

    junk yard kid

    People talk about vinigar rust removal, do you guys think that will work.
  14. shooter54
    Joined: Apr 25, 2006
    Posts: 5,037


    thanks again guys. and if anyone has any more tips about the actual process itself, feel free to chime in!
  15. ClayPigeonKiller
    Joined: Mar 3, 2010
    Posts: 203


    Drain king
  16. 460stang
    Joined: Sep 19, 2010
    Posts: 45


    prestone super flush.. run the engine with that in it, then flush it out, fill with water and run that through and flush that out then fill with collant.. if its really bad. after the first flush. pull the hoses off and flush out each piece with the hose,, engine block,rad, and heater core..and blow it out with air.. this way any rust or crud wont keep moving around the system.
  17. Gasser 57
    Joined: Feb 13, 2007
    Posts: 764

    Gasser 57
    from New Jersey

    This will make one hell of a mess but it works. Get the car up in the air and knock out the core plugs on the sides of the engine that you can get to. Then get a screwdriver to pick at the crud and a water hose with a spray nozzle and go to town. You will not believe the amount of shit that will come out of the block.
  18. shooter54
    Joined: Apr 25, 2006
    Posts: 5,037


    alright. i got a drain king and some prestone super flush. gonna give it a go and see how it comes out. thanks again for the tips everyone.
  19. 63Compact
    Joined: Feb 14, 2007
    Posts: 1,071


    Run a radiator sock in your top radiator hose stops the crap getting in the radiator. I run them on my Windsors as they are notorius for block scale clogging radiators. Just clean em out when you change the oil.
  20. shooter54
    Joined: Apr 25, 2006
    Posts: 5,037


    can you elaborate on the "radiator sock" ?
  21. jimcolwell
    Joined: Oct 4, 2009
    Posts: 469

    from Amarillo

  22. Do Mopar blocks have drain plugs in them as Chevy motors do? Just another way to get to the "bottom" of the problem so to speak.
  23. im not saying its a good idea but it works every time for me . have gallon of white vinegar drain you system fill with water, oh be sure to remove thermo,. fill with clean water and vinegar run for one day or 2 of driving, remove lower hose while still warm ...not hot ......... and now look at the clear water ...
  24. Termites Ate my Chevy
    Joined: Jun 26, 2007
    Posts: 544

    Termites Ate my Chevy

    My dad told me once back in the day they used to use Coca-Cola to flush their cars. Don't know if he was pulling my leg, but it sure is interesting. Coke will dissolve a nail in a couple of days Soooo.....
  25. stealthcruiser
    Joined: Dec 24, 2002
    Posts: 3,668


    Tee Hee Hee..............................They said "sock"!:D
  26. Cymro
    Joined: Jul 1, 2008
    Posts: 648


    I'd go with this one, oxalic acid is fairly weak but very effective, it is found naturally in Rhubarb.

    Cola contains loads of sugar and Phosphoric acid (metal prep)

    Vinegar acetic acid or ethanoic acid dependent on where in the world you reside.

    They all work and will remove rust scale, so basically all being weak acids it takes time so you pay your money and take your choice.
    Joined: Feb 13, 2010
    Posts: 63

    from Virginia

    All the flush suggestions sound good. Just be aware that you might need to replace your expansion plugs when done with the air power flush. I have see leaks occur in this type of situation. The one under the motor mount is a bugger.
  28. d2_willys
    Joined: Sep 8, 2007
    Posts: 4,092

    from Kansas

    I used the Preston Super flush (oxilic acid, with a neutralizer) and it seemed to get alot of the rust out. Make sure you put the neutralizer (sodium bicarbonate or baking soda, I think) after draining the oxilic acid or the seals will be toast. Follow the instructions.

    Before doing the super flush, you may want to get one of the Prestone flush kits and splice the hose connector into the heater hose that goes from the heater core to the intake manifold or thermostat housing. This will back flush sort of because the thermostat will be closed, and only the bypass will allow water through. Most of it will distrubute through the block and then exit the lower hose and into the radiator. This will eventually spew out of the cap fitting. You may want to close the heater valve to allow more water in the block.
    Last edited: Dec 2, 2010
  29. Retro Jim
    Joined: May 27, 2007
    Posts: 3,860

    Retro Jim

    Depending on what engine you have and what it's installed in will make a difference in this method . If your engine block is that bad and you can get to the freeze plugs easily , then do this . It's allot of work but cleans the block out good .
    Open up and remove the block drain plug and use a round wire brush to clean that out so the liquid flows out well through the drain hole . Now drain the block . Now install the drain plug or a bolt back into the block . Unhook your radiator and heater core and remove the thermostat . Make sure there is a way to block off the bottom hose so the liquid doesn't leak . Pour a gallon of vinegar or how much the block will hold . Now connect the top and bottom hoses together . Then start the engine for a couple of minutes but don't over heat the engine ! This will get the vinegar to flush through the entire block real good . Let it sit for a good day or 2 then drain through the block drain plug ! Now flush with a garden hose to see how good it did . If you still see crud coming out , then remove what freeze plugs you can and take a wire brush to the inside of the block to clean all you can and flush water through the freeze plug holes . Yes that is a lot of work but your labor is cheaper than paying someone else to clean the block out . Now do all the freeze plugs you can and flush out real good . Then replace the freeze plugs and thermostat . Connect everything back up and you should be ok . I know it's a lot of work but if your block is that bad there isn't much more to do but pull the engine and tear the engine down ans have it professionally cleaned .
    The vinegar in the block should be good enough but if not then the freeze plug removable will be the other option to get to the problem with a wire brush .
    Good Luck and let us know what worked best to clean that cruddy rust out !

    Retro Jim

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