Review: STP Engine Flush cleaner...

Tried this on today when I was changing my oil. From the look and sound of things, it works. It accentuated my valve slap, so it’s a lot more noticeable now…looks like I’m gonna have to adjust my valves soon. Just some things that you might end up asking:

  • Ran the car with Mobil 1 synthetic w/ Purolater PureOne filter.
  • Oil level was about close to the top before adding the additive.
  • Ran the engine for approx. 23min. at 1500rpm.



A little insight on what engine flush is originally intended for. Older motors, and I mean old, like in the 40’s or 50’s didn’t use an engine oil filter. So, every oil change a flush was necessary because sludge would definitely build up due to the lack of a filter. Modern motors don’t need to be flushed at all according to any type of maintenance schedule because of better formulated motor oils and the introduction of a filtration system. I would say engine flush has more of a chance of being harmful than benefitial.

Example- You have a 10 year old motor, with fairly oxidized neoprene seals or gaskets due to age. (i.e. oil pan gasket) Since the gasket is oxidized and has become slightly brittle, instead of absorbing the cleaning agent and allowing it to evaporate, it would actually begin to erode because of its oxidized condition and inablity to absorb anything. Whoops, you have an oil leak now.