i gave a guy at work a $2 (clearance and rebate) jug of valv 10-40 for his 100$ 93 geo with 200k...he has changed oil maybe twice in 50k so i asked him when he was going to change the sludge and he said DS was low and he added quite a bit of oil so he is quite content to leave "well" enough alone haha...in his mind this counts as a OC, 3 qts of new oil with 2 qts of filthy 5-30 with 20k on it....mobil one should see if anything they make can stand up to his maint schedule..a supertech DIY oil change would be 13$, but that would be 2 packs of smokes and way over maint budget for car...60 miles RT to work too