Engine knock repair charges depend on the damage. A defective spark plug is a cheap remedy. If it's a bigger problem, repairing it could be expensive. To estimate engine knock repair costs, take your car to a competent mechanic. The mechanic will locate the noise and estimate repairs. They might also recommend replacing or repairing engine parts. Repairing an engine knock is also laborious and time-consuming. This suggests that even if the parts are cheap, the repair may cost more than expected.