You really should have done this while the cars were running. Practically eliminates the plume of smoke all at once (you will get a little at a time with the engine running) & the solvent gets dissipated in the intake air stream to coat things better - not just the low spots. Let it cool & sit while you do the oil chnage, then you take it for the drive.
My V-6 Contour I got used & did the first Berryman cleaning at about 70,000 miles - made an immediate improvement.
My V-6 Mystique I got used with 90,000 miles on the clock. Did the cleaning two weekends ago because it was sluggish & didn't pull very well up top. Now it pulls just fine. I intend to open up the UIM/LIM to perform a detailed rebuild in the near future & will do a before/after thingy with a Berryman cleaning. That should address the benefit controversy once & for all.
<<< (reminded to make a how-to for coolant flushing & ATX drain & fill)
