Originally Posted by
nfntruth79
IIRC, it is a big no no to switch between synthetic and back to normal oil and back and so on. It may be snake oil advertising for synthetics, but I can't remember where I read that. I personally have used the QS torque 4x4 in my Isuzu, good stuff, and a decent price. I will never go back to conventional oil again....
It *used* to be a problem in the early days of syn oils. I forget the chemical (esters?) in synthetics that would cause the seals to harden/shrink if you went back to regular oil, but this is no longer the case, and I have read many more recent accounts of people who switch back and forth, mix oils, etc. And the syn blends are already blends... So I'm not really worried.
On my van, I may decide to stick with full syn only to keep my oil changes at longer intervals...it is really convenient just to go 6k before I worry about changing oil. The QS looked great when I drained it after 6.5k miles on it.
George