Perhaps. Back in 1991, my 1978 1/2 ton Chevy used about a half a quart of dino every 3000 miles. I made the decision to switch to full synthetic and it started LEAKING about a half a quart every TEN MILES. Went back to dino and voila ... no leaks and back to using a half a quart of dino every 3000 miles.

So...maybe "that's not true!" in your controlled environment as a Mobil 1 tester. But in my real-world experience, it was 100% true.

At the time, my sister was married to an ASE certified wrench and he laughed at me that I tried to put full synthetic in my truck that had 150,000 miles on it. So either the full synthetic was different back then, or the seals and gaskets were different back then, and the higher-mileage engines bled full synthetic ... for whichever reason.

 

If you have seals and gaskets that are damaged synthetic will point them out, hence why you lost oil when you switched to synthetic.

 

Which was sorta my point the first time around. I was in no way suggesting that synthetic oil will leak in an engine with sound gaskets and seals. What is absolutely true is that if you do have tolerance issues, the dino has likely sludged in those cracked/worn areas...and the synthetic will usually come in and wash all that sludge away. Next thing you have is an engine hemorrhaging synthetic all over your garage floor/driveway/exhaust, etc.

 

Cats? Ain't nobody got time for that. J/k. My dad runs Rotella in his FX4 and 300K plus mile Jeep grand cherokee with no issues.... His vehicles have stock exhaust on them.