I had the car in for an oil change and the guy recommended that he add
this compound to the engine to clean it out. He propped the hood open
and hooked up this bottle of goop. When I fired up the engine some
smoke came out from under the hood and the guy doing the work made the
diagnosis. This was one of those rapid oil change places and I realize
that the workers there have limited knowledge of the vehicles that they
work on, but this guy was in charge of the shop and I have some
confidence in his knowledge.

I've also noticed it is noisy when first started and then settles down
once it's warmed up.