Seafoam is awesome.  I use it pretty much everywhere.  In the crank case before an oil change to clean up sludge and carbon deposits.  It works great.  Although, it's best to start these treatments on an engine when it's new and continue to do so at each oil change.  You can see the how well it's working by how black your oil gets.  I usually run my engine gently with a bottle of Seafoam for 100 miles before each oil change.  By the end of the 100 miles the oil is pitch black.  I also use it in the gas tank to clean up the fuel system.  I usually add 2 bottles of Seafoam to a full tank every 5K miles or so.  And I also use the Seafoam spray in my intake every 5-10K miles as well.  It requires an assistant, so I usually end up having to wait until I can get someone to help.  Seafoam has worked wonders for me in the past.  It freed up a stuck valve in my F150 after about only 10 minutes of a bottle in my crank case.  I've seen it clean large carbon deposits out of the combustion chamber when sprayed through the intake.  It really is my go to source for all performance related cleaning.
Seafoam is awesome. I use it pretty much everywhere. In the crank case before an oil change to clean up sludge and carbon deposits. It works great. Although, it's best to start these treatments on an engine when it's new and continue to do so at each oil change. You can see the how well it's working by how black your oil gets. I usually run my engine gently with a bottle of Seafoam for 100 miles before each oil change. By the end of the 100 miles the oil is pitch black. I also use it in the gas tank to clean up the fuel system. I usually add 2 bottles of Seafoam to a full tank every 5K miles or so. And I also use the Seafoam spray in my intake every 5-10K miles as well. It requires an assistant, so I usually end up having to wait until I can get someone to help. Seafoam has worked wonders for me in the past. It freed up a stuck valve in my F150 after about only 10 minutes of a bottle in my crank case. I've seen it clean large carbon deposits out of the combustion chamber when sprayed through the intake. It really is my go to source for all performance related cleaning.