HELP! Baffling coolant leak

Discussion in 'Chevy Silverado Forum (GMC Sierra)' started by rdoty, Feb 20, 2013.

  1. rdoty

    rdoty New Member

    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. j cat

    j cat Epic Member 5+ Years 1000 Posts

    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. trentkoger

    trentkoger New Member

    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. j cat

    j cat Epic Member 5+ Years 1000 Posts

    if the coolant enters the transmission he would see transmission problems very quickly. it would take very little coolant to kill the transmission .
  5. shibby2oo8

    shibby2oo8 Member 2 Years 100 Posts

    Bet you a millon dollars it the intake gaskets.
  6. Conlan Rose

    Conlan Rose Epic Member 5+ Years 1000 Posts

    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.
  7. rdoty

    rdoty New Member

    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 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. j cat

    j cat Epic Member 5+ Years 1000 Posts

    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. Conlan Rose

    Conlan Rose Epic Member 5+ Years 1000 Posts

    It may be the frost plugs....
  10. rdoty

    rdoty New Member

    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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