Check out this engine compression test, leakdown, and bubble tests. Read more only at www.highperformancepontiac.com, the official website for High Performance Pontiac Magazine!

Diesel engine blowby can be caused by a number of mechanical factors, but there are simple ways to prevent damage and keep your engine purring.

Blow-by can harm an aging engine, but a certain amount is normal for most vehicles. Here is how to tell when there's too much blow-by in your diesel engine.

Not all braking systems on semis have to be loud to be effective. Exhaust brakes make a fraction of the noise that compression brakes do, here's how they work.