Hello Scotty,

I've been watching for over a decade.  This is my first question!  I have a 2017 Smart ForTwo with the M281 0.9L 3-cylinder turbo engine and 6-spd Getrag DCT transmission, I bought it with 59,000km. I'm the second owner and I have the service records that show it had oil changes every 15,000km.  I had a rattle from the engine which I thought was timing chain slap.  It also had a lumpy idle. There are no engine codes. I ran a bottle of Liquimoly engine flush through it and have changed the oil every 3,000km since then and the timing chain slap is gone.  The car now has 72,000km.  I have also pulled the cam phase solenoid every oil change and soaked it in Marvel Mystery oil.  I had been running TC-W3 (SuperTech) two stroke oil at a dose of 1:500 or about 40 mL every tank - I always do the math so as not to overdose.  The car does seem to run better when I use it.  Is there any harm in using TC-W3 at every fillup?

Thanks very much.