Originally Posted by bmwpk
Awesome write up. How did the car feel afterwards? My 330i has been idling funny. I cleaned maf and just put in new spark plugs, this maybe my next step.
Smoother idle, smoother from 2500-4000, with a less gruff sound. Acceleration feels a just little more free. I had thought my engine was aging well, but in the week or so after I used this I realized that I had simply become accustomed to very slightly degraded performance. None of the changes were huge, but it was worth it.
Also, since I ran it through my crank case (a few weeks before I did the above tutorial) my mileage has improved. This hadn't happened in previous cars I'd Seafoamed (indeed, my truck actually had decreased
mileage), but I'm getting maybe 5-8% better mileage on the highway. I don't have a large enough city sample to say anything on that, but in a couple of lengthy highway drives I have really noticed a difference. I expect this to be temporary, and, literally, your mileage may vary, but that's the experience I've had since Seafoaming. I also changed the plugs, so that undoubtedly has something to do with it, but I'm getting better mileage than when the car was new.