First things first.

Car: 2007 Mini Cooper S with 58k miles.

Had the timing chain replaced and valve cover gaskets replaced.

Prior to those issues, it had already lost a lot of the power that made me fall in love with it. It feels as though the turbo isn't doing it's job. However, when I lift off the throttle at high revs, I can hear the diverter valve making the "hiss" noise. So I assume it's not the diaphragm, however - I am no expert on that at all.

I've done 2 passes of Seafoam so far and it no longer blows out white smoke when it passes through the system, so I assume the carbon buildup isn't as bad.

I've put new spark plugs (NKG) in it just yesterday.

I'm not getting any CEL's so I've really got no where to start. Anyone here have any ideas? Thanks!

 

Imo seafoam is more of a little bit of a cleanup, but not a fix for more extensive carbon issues....might still be worth getting it done manually....the reason it is done is chemical cleaning can remove some of the newer buildup, but not the older, baked, caked on stuff....not a gen2 guru, but thats my suggestion. You could have a quick compression check done, or check your boost level with a guage....all pretty simple.

 

I'm with zippy... carbon cleaning time!

 

Will take those suggestions and see what happens. Also will report back once I've given it a go. Thanks!