Expert: Brad Sears - 5/18/2011

Question
QUESTION: I was recently changing the water pump on my 289. While tighting the bolts down the 3 1/2 in bolt on the drivers side of the water pump, broke loose and would not tighten very well, it kept slipping.  This bolt goes through the water pump, through the timing cover, and threads into the block.  I finally got it a little snug and checked for leaking.   When I started the engine and filled it with coolant, there was not leaking on the water pump, but I noticed that where the bolt tightens into the block, it had cracked out on the top and side.  Both cracks are about 1 inch long and do not go back into the block under the heads.  It is only cracked where the bolt enters the block.  Is there anything I can do to repair this, or do I have to get a new block since this one is cracked?  I have attached pictures of the crack.

ANSWER: Before I answer that question I have a question. How comfortable are you removing the timing case cover? How comfortable are you drilling straight holes with a hand held electric drill? Do you have a Dremil tool? Let me know. If you are comfortable then thee is a procedure that I can lead you through to repair this without removing the engine.

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QUESTION: I have not issues removing the timing chain cover or drilling.  I have a dremel as well.  I was already planning on removing the engine as there is some other work in the engine compartment that I would like to get done.

Answer
Good. I did this repair a while ago. What I did was to drill a small hole at the end of the crack. Then using a cut off wheel on the Dremil I opened the crack about a 1/16th inch, but not all the way through to the thread. Then I packed JB weld epoxy into the cracks an a cover coat. After that dried for several days I taped the bolt hole to clean up the threads. It worked, But if the threads are damaged you can fill the hole with JB, redrill it using the timing case cover as a guide, and then retread. It worked for me and the car is still running.