There are a few video's of this aircraft flying. The engine is marked as DB 601 N version, W.Nr 67303. The VDM propeller has modern manufacture composite blades. The engine sound is a little distorted on this recording, but it sounds much more like the gruff DB on other recordings of this aircraft. The cowlings are removed and the crew seem to be tracing various leaks with absorbent paper. Leaks and weeps can be difficult to trace on large engines, especially as an after-flight inspection will show oil splashed about everywhere! Here they are looking after a short run-up, with paper strips all over the place. These 109 E cowlings are more complicated to remove than the later F/G/K, the lower cowling particularly, so I guess that the owner/operator gets worried with the amount of oil in the lower cowling.
For those who are interested, other recordings show that this aircraft has the throttle mounted prop pitch control switch (Daumenschalter).
Eng