I was just talking to a guy here at work and he mentioned getting an engine flush from Jiffy Lube for like 80 bones and was raving about how well his engine is running now and that it improved his gas mileage by an extra 40mi a tank. Well, a little curious to as how they do this and what is used; I did some research on google and found that more than anything else, people were really displeased with it.. Mainly due to the fact that the kids that worked there had made stupid mistakes by not tightening things, misdiagnosing, and ruining parts that weren't broken to begin with.

So, besides the fact that they can mess up your car, does anyone recommend this if done under supervision?

Also, what's the difference in using one of these engine flush machines and using seafoam? I know that on the bottle of SeaFoam, it has applications for cleaning out your oil system too. Since this is what they are doing at JL with a machine, would it be better just to SeaFoam it yourself, -OR- have this done AND use the foam in addition?