Intake or Head Gasket question.

Discussion in 'The Bench' started by eagleguy, Dec 8, 2019.

  1. eagleguy

    eagleguy 1971 Skylark Custom

    After a lot of going back and forth with my carb which dumps fuel and my tranny with a stuck modulator I have come to the conclusion that I may be leaking coolant internally as my radiator level has dropped, still have white smoke and water droplets from the tailpipe. Plugs still look fine and I still have no water in the oil or oil in my water/coolant. Is there an easy way of telling which gasket(s) I may have blown? The motor, a 1970 396 was rebuilt not long ago and everything looks normal. I was going to drop in some of those AC/Delco coolant tabs as recommended by someone in my car club but I am not looking to band aid a serious problem even though I am not looking at the cost of having to possible do the head gasket(s). Smoke is the same out of both exhaust tips! Thanks in advance for opinions and/or ideas.
     
  2. BBBPat

    BBBPat Well-Known Member

    You can get a hydrocarbon test kit to analyze any petro stuff in the coolant. Pressure test the cooling system. It should hold pressure overnight(ish). White smoke out the tailpipes is a sign of coolant. Water droplets are unburned hydrocarbons mixed with atmosphere making water. Put a cup under the pipe and let it drip into it. Do the taste test. Taste sweet or cruddy? Wont take more than a drop or two to taste that one.
    Its either intake or head gaskets. Coolant will steam clean the spark plugs (and piston tops). If you do a compression leak down test, the radiator may bubble or hear a hiss out the tail pipes or carb.
    Could also be a minor crack between an intake and water port(passage) in the block or the head. Try some alumaseal powder for a quick sealant. Is the coolant loss noticeable?
     
  3. TexasT

    TexasT Texas, where are you from

    Yes, a compression test and leak down should be first on the list. Do the leak down with the radiator cap off so you can see if there are bubbles in the coolant. Also listening in the 710(oil if it is right side up) fill hole, carb and tail pipe to see about leakage out a valve or hg.

    Is it smoke or steam from the tail pipe?
     

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