How do you replace head gasket on north star motor?

Answer 1

Most Northstar head gaskets fail because the cylinder heads do not stay tightly bolted to the engine block. Northstar engines produced in the early and late nineties used relatively small diameter head bolts that over time, pulled and damaged the threads in the aluminum engine block. Later models used larger threads on the head bolts, which helped but did not eliminate the problem. The solution is to remove and dis-assemble the engine in order to drill and tap head bolt threads in the aluminum block with much greater surface area and holding force than the originals provided. Typically a 5/8-inch x 11 thread per inch tap is used to create nearly two inches of threads in the block for each of the twenty head bolts These much larger threaded holes can then be used to install either steel studs or inserts that provide a permanent strong anchor for holding the cylinder heads and gaskets more securely in place. This repair requires precision, special skill and tooling, and typically costs thousands of dollars to accomplish. The procedure is documented in detail online and can be located with a simple internet search. This is not a repair that should be attempted by a typical do-it-yourself mechanic.