15W40 Rotella may leak less. Old school believes synthetic may release some old conventional oil that was functioning as part gasket part sludge. But the fact is that you have a leak, from what ever cause. Maybe leak is from the front cover gasket. But one thing is certain, it is really a Rover, and not some knock off. If there's none under it, there's none in it.

Did you clean out your PCV system, if it is clogged the internal air spaces in the engine can build up pressure from oil fumes and vent in strange places.

 

I switched to 15w40 Rotella last night.

I inspected the front of the oil pan while the engine was running and I was able to observe that the leak was coming from the oil filter adapter housing and not the oil pan gasket. I did some digging and there is a TSB regarding this housing...apparently the housings were manufactured with insufficient flatness tolerances which creates a poor mating interface between the block and housing.

I also checked the pcv system. I removed the spiral "oil separator" that is inserted into the vent nipple on the passenger side valve cover. While extracting the oil separator the top broke off. The separator was fairly gunked up but wasn't clogged. I went ahead and put the hose back on w/o the separator.

Has anyone tried swapping out the spiral unit with a standard inline PCV?

 

You can buy a new spiral part. The baffle inside the valve cover prevents parts from dropping down inside. Also need to clean out the passages the driver side.

Would like comment from others on fix for machined part issue.