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Radiator is starting to rust inside

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by UseYourBlinker, Apr 16, 2003.

  1. UseYourBlinker

    UseYourBlinker 1 ton status

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    Figures... I am having no cooling problems,but the coolant is deep brown color. I flushed the radiator 3 times yesterday,and the new coolant I put in (Green) is brown only after a day. Is it possible to get the radiator hot dipped,or should I just buy a new one? If I get a new one where should I shop around at? Thanks guy's & gal's

    1984 K5 Blazer
    350ci 5.7 liter
     
  2. 4x4Freak

    4x4Freak 1/2 ton status

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    The radiator wont rust, it can become corroded with mineral deposits though. It is made out of copper. It could be the engine or water pump as they are made out of cast iron. Or if you have a bad head gasket, the exhaust could be seeping into the coolant passages.
     
  3. dyeager535

    dyeager535 1 ton status Premium Member

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    I don't think I'd spend money on having one dipped or trying the chemical cleaners in it. Unless you can flow test before/after, I don't trust those things. I've tried it, didn't work.

    Rodding the radiator or re-coring are an option depending on cost. New radiator is typically about $120-200 depending on size, so you've got to weigh the cost and shape of yours. Even if you have it rodded, whats to say the thing isn't corroded enough that in 1 year it will start springing leaks?

    I thought there is someplace that members get a better deal from on radiators, try a search I guess.
     
  4. Goober

    Goober 1/2 ton status

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    Sure, you could pull it out and have a shop clean it out for you. It couldn't hurt but it might not cure the problem.

    There is nothing inside your radiator that will rust or turn brown. However, your cast iron engine block will rust like crazy if you don't have the right chemicals in there to stop it.

    Go buy yourself a Flush-n-fill kit and douche all the gunk out of your cooling system. Since you already have a nice buildup, you may want to add some "radiator flush" before actually changing the coolant.

    [​IMG]


    There are many different brands but they are all pretty much the same. They are really just a weak acid solution that you rinse through the system for a few minutes before changing everything. They are designed to get rid of the rust scale and deposits that are in your coolant system. The stuff is easy to use and it's cheap.

    Once you get it all cleaned and rinsed out, fill it up with propylene glycol antifreeze rather than ethylene glycol.

    [​IMG]

    It's will cost a few bucks more ($7/gal instead of $4) but it's worth it. The benefit of the propylene glycol is that it won't kill your pets or the fish in the streams when you spill it on the ground and they drink it. Ethylene glycol is sweet and animals just love it. Watching an animal die from ethylene glycol poisoning is awful.


    The new antifreeze will have all the anti-rust, anti-corrosion and lubrication additives that you will need.

    It shouldn't take you more than an hour on a Saturday afternoon to install the kit and flush out the entire system.


    Have fun! /forums/images/graemlins/grin.gif
     
  5. UseYourBlinker

    UseYourBlinker 1 ton status

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    Thanks for the help fella's.. Look's like I'll try the flush kit first before I go out and buy a new radiator. Agian thanks alot. /forums/images/graemlins/thumb.gif
     
  6. dyeager535

    dyeager535 1 ton status Premium Member

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    All I've got to say to follow up is, if your radiator doesn't rust, and it's the block, what exactly has been preventing the radiator from corroding?

    You are seeing symptoms of anti-corrosion inhibitor breakdown. That means NOTHING has been protected in the cooling system.

    If your vehicle still cools ok, you will probably be fine and caught it in time, but if your temperature easily fluctuates by a fair amount (I'd say up around mid point on the temp gauge) under load, the radiator needs help.
     
  7. BlazerGuy

    BlazerGuy 3/4 ton status

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    If you have to buy a new one, I bought one from AutoZone around the 130 range for a 3 row. I think it has a lifetime warranty but I can't remember. I think you can get cheaper deals with the CK5 membership from Radiator.com though...
     
  8. chevy4x4boy

    chevy4x4boy Registered Member

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    wow i went to radiator.com and this technician actually chatted with me about my install!!! thats sweet!
    /forums/images/graemlins/usaflag.gif /forums/images/graemlins/k5.gif
     
  9. wrathORC

    wrathORC 1/2 ton status

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    Drain your radiator and pull the block plugs and drain the block while trying to catch as much antifreeze as possible. Empty the lower radiator hose too and yank that upper radiator hose as well. The block plugs are easy to get to, they're a few inches away from the motor mounts.

    When no one is looking get out the garden hose and flush out the block. Keep dumping water in until you don't get any more crap rolling out the block drains. In my experience, there is a lot of crap in the block. I've actually pulled out pieces of casting material out through freeze plug holes. All of this stuff promotes rust and those cheesy radiator cleaners usually just loosen it up so it ruins water pump seals.

    Anyway, refill with 50/50.


    In my experience, those radiator flush things aren't worth squat. I've tried them all. I found CLR works just as good on radiators. And it still leaves a lot of calcium in the radiator (freaking idiots that don't use distilled water in their cooling systems...).
     
  10. Ryan B.

    Ryan B. 3/4 ton status GMOTM Winner

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    Eric-
    When i re did my whole cooling system on my car, with a new BeCool radiator, I only use distilled water from the grocery store to fill the radiator now because it won't have all the minerals of tap water. /forums/images/graemlins/thumb.gif
    Also I invested in a RAD CAP which i've seen at the goodguys shows for $20. They have a sacrificial anode that all the positively charged ions in the coolant go to the anode attached to the radiator cap, and corrode that instead of expensive aluminum heads or water pumps. /forums/images/graemlins/thumb.gif
    I've had a water neck off the manifold corrode completly through before. /forums/images/graemlins/eek.gif
    If you have a 3 row radiator this could be an excuse to upgrade to a 4 row. /forums/images/graemlins/confused.gif /forums/images/graemlins/k5.gif
     
  11. UseYourBlinker

    UseYourBlinker 1 ton status

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    More great info guy's! Thanks...gonna flush the bad mofo Sunday /forums/images/graemlins/thumb.gif
     

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