Here's why:
* Head bolts are stretch bolts (or torque-to-yield bolts): These bolts are designed to stretch during tightening to a specific torque. Once stretched, their structural integrity is compromised. Reusing them means they won't stretch properly, leading to:
* Improper clamping force: The cylinder head won't be clamped down sufficiently, leading to leaks (oil, coolant, combustion gases), potentially catastrophic engine failure.
* Uneven clamping force: Some areas might be adequately clamped, while others aren't, leading to warping of the head or block, further compounding problems.
* Head gasket failure: The gasket won't seal properly, leading to the aforementioned leaks and engine failure.
* Potential for bolt breakage: A reused bolt, already stretched beyond its design limits, is far more likely to break during tightening or under engine operating conditions. A broken head bolt can be incredibly difficult and expensive to remove, often requiring engine removal.
* Safety risk: Engine failure from improper head bolt torque can cause significant damage, potentially leading to injury or even death.
In short: The cost of a new set of head bolts is far less than the cost of a blown engine, significant repair bill, or potential injury. Always replace head bolts with new ones of the correct specification when doing a head gasket job. Using the wrong type of bolt can also lead to disaster. Consult your repair manual for the proper torque sequence and specifications for your specific Grand Am GT's engine.
