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  1. #1

    Question HELP! Baffling coolant leak

    I've got a 94 Silverado K1500 4WD with a frustrating coolant leak. I've got it under pressure (15psi) and there's almost no drop over time (1 hr). I can see drips of coolant near the transmission but couldn't find the source. The baffling part is this: There are two struts to the bottom of the bellhousing and where they attach to the bellhousing both bolts have a drop of coolant on them. The struts themselves are not wet. Then laying there on my back I notice a drop of coolant appear on one of the transmission coolant lines! It appears that the lines at one time had battery acid on them because they look corroded. But the coolant drip is definately coming from one of those lines.
    Do those lines have coolant in them or transmission fluid? Also, why would the strut attachment bolts have fluid on them? There is no spray of coolant. It's as though coolant is coming from inside the bellhousing.

    Answers please!!!

  2. #2
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    since this is a small leak on a 1994 I would use some bars stop leak. pre mix 1/4 of the stop leak in some distilled water just enough to allow the material to loosen up . then pour into the radiator , not the coolant recovery bottle. drain some coolant out so this can be done.

    If this is a crack or freeze plug leak this should work. even if its a small gasket leak.

    I am assuming that you have properly maintained the coolant system and you have no corrosion and the correct amount of coolant concentration. 50% min . best to use 65% for max corrosion protection with distilled water and NO scale build up.

  3. #3

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    The early 90s K model pickups had terrible radiators in them and they would leak through to the tranny cooler that is mounted on them this sounds like part of your problem.

  4. #4
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    Quote Originally Posted by trentkoger View Post
    The early 90s K model pickups had terrible radiators in them and they would leak through to the tranny cooler that is mounted on them this sounds like part of your problem.
    if the coolant enters the transmission he would see transmission problems very quickly. it would take very little coolant to kill the transmission .

  5. #5

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    Bet you a millon dollars it the intake gaskets.
    01' 1500 LT Z71 ECSB 5.3L
    line-x'd front brush guard with KC Daylighters, 6000k HID lows and highs, rewired highbeams, Trans-go mild shift kit, custom stainless duals, 3500 dually OEM taillights, K&N CAI. Still have OEM fender flairs and leveling kit in boxes waiting for time.


  6. #6

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    I own one of these 90's trucks and yes the leak can be anywhere.... check the radiator, hoses, clamps, freeze plugs, gaskets, every thing. If you have stock dex cool it should be easy to find if you clean the engine because it is bright orange.

    1996 Chevy Tahoe LT 5.7L V8 4X4 205,000+ miles. Built proudly at Janesville Assembly in Janesville, Wisconsin
    Basic mods: Lights all over, bunch of electrical work, and a couple cooling mods.

    Check out my other mods in My Garage: http://www.gmtruckclub.com/forum/sho...t-Tahoe-4-Door

  7. #7

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    Well, it took a couple of drops of coolant on my forehead and glasses but it's not coming from the transmission cooler lines (duh!) but from somewhere above. Did have a local guy tell me that it couldn't be the head gasket because those would leak inward so it has to be the manifold gasket. It's so tight back there that I can't see anything even with a mirror. One big question....is there anyplace else that it could be coming from other than the manifold? Just want to be 95% sure before I turn somebody loose on this.

  8. #8
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    Quote Originally Posted by rdoty View Post
    Well, it took a couple of drops of coolant on my forehead and glasses but it's not coming from the transmission cooler lines (duh!) but from somewhere above. Did have a local guy tell me that it couldn't be the head gasket because those would leak inward so it has to be the manifold gasket. It's so tight back there that I can't see anything even with a mirror. One big question....is there anyplace else that it could be coming from other than the manifold? Just want to be 95% sure before I turn somebody loose on this.
    you turn that loose on some one , an they start taking that engine apart you better have a couple thousand ready.

    try the stop leak as I recommended this is a quick way to determine if its a leak that requires engine break down.

    I use this product on the old high mileage engines and it works so long as the system is clean .

  9. #9

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    It may be the frost plugs....

    1996 Chevy Tahoe LT 5.7L V8 4X4 205,000+ miles. Built proudly at Janesville Assembly in Janesville, Wisconsin
    Basic mods: Lights all over, bunch of electrical work, and a couple cooling mods.

    Check out my other mods in My Garage: http://www.gmtruckclub.com/forum/sho...t-Tahoe-4-Door

  10. #10

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    Since the leak is from the rear of the engine I think the expansion plugs probably aren't the problem. Correct me if I'm wrong but I think there's two in the back of the engine and they're inside the bellhousing so if that's the case the coolant would be dripping from the drain hole at the bottom of the bellhousing. Can't find any photos that show them but from an internet search that's what I think.

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