'04 Chevy Silverado coolant leak

Discussion in '4x4 / Truck Forum' started by fallsflight, Aug 23, 2017.

  1. fallsflight

    fallsflight Elite Refuge Member

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    2004 Silverado 1500 5.3 Z71 is leaking coolant AFTER the engine has cooled down and not noticed under pressure while running and not until engine cools down. Seems to be coming down from passenger side as seen in picture up above that black plastic clip. Thought it might have been gaskets for the water pump. New ones installed and still leaking. Weep hole is dry after running and engine still hot. Seems like if it was coming out of that, it would happen while under pressure. Could it be the thermostat gasket? Anyone had this happen with their Silverado?
     

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  2. SB2MAG

    SB2MAG Elite Refuge Member

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    At 125,000 miles, mine (2004 Silverado 5.3L) started burning oil and coolant. Plus leaking coolant. I could not tell where it was leaking. It was on the floor in the garage. I put a new engine in it and 800 miles later it started to burn a lot of oil. Chevy rebuilt that engine and 250,000 miles later, this engine doesn't burn any oil or coolant.

    375,000 miles and I can't complain too much.
     
  3. TheDuckSlayer

    TheDuckSlayer Elite Refuge Member

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    Coolant often leaks out of the weep hole when the engine is hot, but you won't see it because it evaporates as soon as it comes out.

    Take your serpentine belt off and try to move the water pump pulley back and forth, front to back (in the same motion that you would do a tire to check for a bad wheel bearing). If there is any play in the pulley, the internal seal is gone and the pump needs to be replaced.

    Even if there is no play, this doesn't guarantee the pump is good. On an '04, it's way overdue anyway, and for less than $100, you should have put in a new pump when you replaced the gaskets.

    I highly doubt it's the thermostat gasket. Check for play in the pump pulley and report back. Also look for residue around the weep hole.
     
  4. tcc

    tcc Elite Refuge Member

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    ^^^ This. I'd go ahead and change that water pump, they're cheap and it's an easy job.
     
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  5. Tailfeathers

    Tailfeathers Elite Refuge Member

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    Ditto on the wp replacement. Might as well change the belts too if they look cracked, tired etc.

    Should be somewhat easy to see where it is leaking from, once/as she cools.
     
  6. TheDuckSlayer

    TheDuckSlayer Elite Refuge Member

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    Check you're radiator thoroughly, too. The plastic tanks on those radiators like to crack, and if it's the original radiator, it's bound to fail soon if it hasn't already.
     
  7. CookMan

    CookMan Elite Refuge Member

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    I would go to a real mechanic. Just like some Bozo posting here about chest pains and "what should I do"? Really, go to the Cardiologist and get checked??
     
  8. tcc

    tcc Elite Refuge Member

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    Or he could do as suggested and save that money while learning something along the way. I've used message board posts to solve and help repair countless issues; sometimes all you need is a little guidance to figure something out. There's simply no reason a grown man should need a mechanic to fix a leaky cooling system.
     
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  9. Tailfeathers

    Tailfeathers Elite Refuge Member

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    I would also go to a Chevy Forum and post. I have gotten excellent info with my cars, trucks and boats on the different forums, usually excellent info by guys that are Techs or know the vehicles inside and out. .
    Plastic radiators? Don't get me started.
    My son was driving me in his newly registered 1998 car when he was a Sr in High School. We just bought it the last weekend and he had polished it all up and cleaned the interior etc.and were were both causing and smiling ear to ear, on top of the world. We are driving along and all of a sudden steam explodes out under the hood with antifreeze all over the windshield. He kinda got excited, I laughed and I guided him into a parking lot. Popped the hood and sure enough, the fantastic Plastic pipe on the plastic radiator snapped off in the hose. Metal would have never done that. We went to a Northern Tool store right there. I took a piece of paper and traced the diameter of the pipe hole in the radiator. Found a threaded pipe fitting that was close in size. Screwed it into the plastic hole in the radiator and used the hose clamp to secure the hose on the other end of the pipe. Went to a laundromat right there and borrowed a pail of hot water and refilled the radiator. Let the water sit a little. Started and ran her home with the radiator cap on one notch, locked on but not sealed, not building pressure. Bought a new radiator on line, a good German aftermarket for $120. Next weekend we installed it. Father and Son grease monkeys. We laugh about it to this day. 5 years later, he finished HS and College, making good money. He buys a 3 year old BMX rocket ship, I call it, twin turbo, freakin beautiful. Dad gets the old 98 and loves it.
    Life is funny.
     
  10. Fowler267

    Fowler267 Elite Refuge Member

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    If it's not the water pump, it could be the intake gasket. Chevys had trouble with the Dexcool antifreeze affecting the intake gaskets. I had issues on an 02 350 but none on an 05 327. It dribbles out behind the water pump on mine.
     

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