WARNING: long and boring introduction. vehicle #1: 1998 Volvo S70 T5 with 118k(2.3L inline 5-cyl 236hp high-pressure turbo) , purchased by the Mrs. back in 2001 with 37k. it received 3-4k dino OCI from an indie volvo mech before I assumed maintenance duties of this car in 2004 when the car had ~85k and started a 4-5k OCI with Supertech synthetic 5W30/10W30 depending on the season. There is some oil seepage from the turbo oil return lines(considered by some to be normal), but not enough to fall on the driveway. I'd say there is maybe a 1/2 qt of oil loss during the 4-5k syn oci. I do see some carbon deposits and varnish underneath the oil filer cap(picture so be taken shortly). I am using ST syn 10w30 during the clean phase with a plane jane purolator filter. i will be following the sludge procedure as listed on the auto-rx website. vehicle #2: 2000 Volvo V70XC with 121k(2.4L inline 5-cyl 190hp low-pressure turbo), purchased by yours truly back in march 2008 with 114k. dealer serviced from day 1 with full records with dino OCI, but there was an unfortunate stretch where it went 7k on dino just before i bought the car as the car was diagnosed with a failing catalytic converter+o2 sensors by the dealer and the previous owner opted not to fix it(which is another story for another day). the problem ended up being lazy o2 sensors which i replaced myself and there hasn't been an emissions-related engine light code since the new o2 sensors(13 months and 7000+ miles and counting). since i've assumed ownership, the car was also converted to ST synthetic at 114k march 08 and at 118k nov 08. this car also has some oil seepage from the return lines that don't make it to the ground. i did have a recurring P0014 code from march 2008 to dec 2008 during which resulted in replacement of a variable valve timing solenoid and the camshaft position sensor before i learned that the engine code could also be caused by sludge buildup on the VVT hub and could also be caused by low oil levels and/or poor oil quality. i've been keeping an eye on the oil level and the car has not had the P0014 code since Jan 2009. i've also installed a boost gauge on the car in the a-pillar and it's reading -16 to -17 hg w/ the car in gear while stopped and -20 to -22 hg in decel on the highway. I am using RTS 5w40 with an OEM Mann/Mahle filter during the clean phase. i will be following the sludge procedure as listed on the auto-rx website. moderate carbon deposits and vanish on underneath the oil filler cap. the gauge reports that i am getting 6 psi of turbo boost which is meets factory specs for the 2.4L LPT turbo. i've saved the XC's cartridge style oil filter from the last oil change back on 04/05/09 the just before the auto-rx was added with RTS. if i get around to it, i hope to have all FIVE oil filters photographed during my auto-rx session (pre-rx/clean#1/rinse#1/clean#2/rinse#2).