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  1. #1
    Jr. Apprentice
    Join Date
    Apr 2011
    Location
    Elmendorf Air Force Base, Alaska, United States
    Posts
    10

    Angry Constant coolant loss

    I have an '04 Silverado with the 4.8 liter V8. I don't see any external leaks but my coolant keeps going low. I have to keep topping off my coolant or my engine will run too hot. Do any of you know what the issue could be? I have heard of cracked cylinder heads if they are from Castech. I can't find a whole lot when searching for Technical Service Bulletins.

    Thanks.

  2. #2
    Jr. Mechanic
    Join Date
    Nov 2011
    Location
    Central Illinois
    Posts
    129

    Default

    If you can't find a leak I would guess you are burning it. Cracked head, bad head gasket, something.
    How many miles are on it? How much coolant are you using?
    2012 Silverado 1500 LT 4X4
    2003 Suburban LT 2500 6.0L
    2004 2500HD Crew Cab LT 4x4 6.0L - SOLD

  3. #3

    Default

    Have you looked at your motor oil to check for moisture in it? Any moisture in the passange floor board?
    Please Tell Your Boobs To Quit Staring At My Eyes

  4. #4

    Default

    Have you done a pressure test on the cooling system? Does it drip on the driveway when you park it? Hopefully, it's just a weeping water pump or a seeping hose.
    Good Luck and God Bless
    Remember that if you're not part of the solution, then you're part of the problem!

  5. #5
    Jr. Apprentice
    Join Date
    Apr 2011
    Location
    Elmendorf Air Force Base, Alaska, United States
    Posts
    10

    Default

    I have checked my oil several times and have not seen it turn milky. I had a radiator flush done on it and they said no leaks were detected. I am quite certain it is being burned or it is evaporating in the heads or something like that. My exhaust isn't smokey. I have not seen any liquids on my floorboard. My truck has around 97,925 miles. I have had to top it off with about half a gallon of coolant once a month. It gets low pretty quickly.

  6. #6
    Jr. Mechanic
    Join Date
    Nov 2011
    Location
    Central Illinois
    Posts
    129

    Default

    Try some coolant dye. If there is a leak anywhere you will see it. It's cheap and easy.
    You can also look at the plugs. If one or more is whiter than the others it is possible that cylinder is burning coolant. You can also give the exhaust a good sniff. A sweet smell would indicate coolant.

  7. #7
    Jr. Apprentice
    Join Date
    Apr 2011
    Location
    Elmendorf Air Force Base, Alaska, United States
    Posts
    10

    Default

    OK I'll give those things a shot. Hopefully it narrows the possibilities down. Thanks!

  8. #8

    Default

    Are these motors susceptable to intake manifold coolant leaks?

  9. #9
    Jr. Mechanic
    Join Date
    Nov 2011
    Location
    Central Illinois
    Posts
    129

    Default

    Yes. Dexcool, as it gets old, has been known to degrade the rubber seals around the intake ports.
    It is supposed to be good for 100,000 miles but I wouldn't recommend running it that long.

  10. #10
    Master Mechanic Jimmeh's Avatar
    Join Date
    Apr 2009
    Location
    Columbia Falls, Montana, United States
    Posts
    806
    Blog Entries
    3

    Default

    Good info. I have had this same problem with no leaks to be found and no moisture in my oil either. Will be switching from Dexcool ASAP.
    2005 Chevy Silverado W/T
    4X4|4.8 with some mods (has only slightly more pull than a 5.3)|Auto|4 door ex cab|Cooper Discoverer AT/3's in 285-75/17's on Helo 842's|Cooper Discover M+S 265-75/17's on Devino DV349's|Flowmaster 40 Single in Dual out with custom bent pipe from the end of the cats back|2" Procomp leveling kit|Custom made center console|Custom dyno tunes|Air Raid CAI|Air Raid Throttle Body Spacer|Apex brand topper|Kenwood Head Unit with Kenwood speakers|Painted mirrors/grille|Debadged except front emblem|Bilsteins front and rear
    Planned mods not in order
    2 inch lift|Custom front/rear bumper|hitch tire carrier|roof basket on topper, bars on cab|finish center console build|install Midland CB|Power options|Tint|Custom made raised bed in the bed of the truck|Lund LunarVisor
    Also have a 1992 Ford Ranger with a lot of stuff done to it. Currently waiting for a bit of a rebuild.


    "The only woman I'm pimping from now on is Sweet Lady Propane. And I'm tricking her out all over this town."

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