A blown head gasket is one of the easiest things to diagnose and repair. You can do it in your home garage with basic tools. But finding a faulty temp sensor that is throwing a code that in turn disables throttle response ... that requires a cloud-based network solution to properly lookup the deliberately cryptic error code.
accurate only if you don't warp the head badly enough that it needs to be machined or replaced outright. Even so, crate motors are surprisingly affordable.
