AMSOIL Engine and Transmission FlushA reader asks: I would like to perform an engine flush on my Ford 6.7L PowerStroke engine before switching to synthetic oil. How many bottles of AMSOIL Engine and Transmission Flush will do the job?

Our Answer: The number of bottles of AMSOIL Engine and Transmission Flush needed to flush an engine is based on the crankcase capacity. As diesel engines have larger oil capacities, they tend to require more than one bottle. Your 6.7L PowerStroke engine holds 12.4 litres (13.1 US quarts) of engine oil and therefore will require 2 bottles of AMSOIL Engine and Transmission Flush.

Below is the application rate for AMSOIL Engine and Transmission Flush.

Shown on the left is the engine oil capacity and on the right is the number of 473 ml (16 oz.) bottles of AMSOIL Engine and Transmission Flush required.

  • Up to 9.46 litres (10 US quarts) – One Bottle
  • 9.46 to 18.9 litres (10 to 20 US quarts) – Two Bottles
  • 18.9 to 28.4 litres (20 to 30 US quarts) – Three Bottles
  • 28.4 to 37.85 litres (30 to 40 US quarts) – Four Bottles

Doing an engine flush prior to using synthetic oil for the first time is a smart, cost-effective maintenance practice. This applies to both gasoline and diesel engines. The AMSOIL Engine and Transmission Flush cleans out deposits, gum, varnish and soot so that your new synthetic oil is not cleaning up these undesirable combustion by-products and sending them into circulation. This practice is especially helpful for diesel engines as they generate much more soot than gasoline engines.

High-quality synthetics oils like those from AMSOIL have strong detergent capabilities that will clean up deposits over time. It is a good idea to go after engine gunk with AMSOIL Engine and Transmission Flush so that your engine is starting out with a clean slate.