Have them too. Correct methodology, poor choice of RTV. It works for a while. It not made to resist the
antifreeze, just like the problem with gear
oil. Right Stuff works great too, but again wrong application. For decades used RTV Blue to make all my lovely Ford blue blocks. it is not a matter of if, but when, especially on Windsor series. Yes, i have had it works for years without a problem, other times right off the bat.