Man, that’s wild. 10w-30 is a less desirable oil than 5w-30 as it’s thicker at start up. But I don’t really see how it could leak more than 5w30 unless it had a different add pack that caused leaks. But then they’d be there after the fact, at least for awhile. And even that seems unlikely. Were they the same brand, just a different weight?
Exact same brand, just different viscosity.
I was going nuts checking PCV valve, hoses, vacuum leaks, everything.
It has been doing great, then all at once I start having these problems.
It was by chance I was looking for the oil jug I knew was the right one for what I had used, to add more oil, and I discovered that both jugs were the 10W-30.
I was about 4000 miles on that oil, (I normally run 7000 miles per change) so I decided to change it. I did it to rule out that as an issue and the problem went away.
I always use Quaker State 5W-30 regular dino oil. I do not use the synthetic high mileage version.
I do Blackstone lab analysis every two oil changes to monitor metals levels and silica levels as well as coolant to make sure I head off any issues.
I saw a spike in silica and discovered a hole in my air filter, so I changed the filter and it came back down.