W124 M119 1994 E420 cam lubrication
 

Hello MB'ers,
About 400km ago, our 60k Km E420 started ticking from the passenger bank.
A fairly common issue on M119 engines is a blown cam oiler tube, so we sourced a set of aluminum tubes and new MB O-rings.
On removing the cam blocks to access and replace the oiler tubes we found two worn exhaust cam bearings that smelled of overheated oil. The cam looked ok, though haven't removed it yet to measure.
My guess is that there is a blocked oil gallery that feeds those two bearing blocks and the ticking lifter.
The last 50km driven showed higher than normal operating temperature (100C instead of 80C) and lower than normal idle oil pressure.
This car has been with us for 20K Km, always with synthetic oil. The previous owner claims same.

Questions:
Has anyone ever heard of only a couple of bearings on a cam AND a lifter not receiving lubrication?
Is there any way to use compressed air to blow out what could be a plugged oil gallery?
Do I have to lift the cam to access the gallery? It's the two bearing caps that have plain bearings toward the rear of the engine, before the rearmost grooved bearing cap.
TIA,
Odd