[C320-list] Perkins motor oil filler

[Dave Hupe]

 Dave-
You are absolutely correct.  If you remove the right cap (just like a car radiator cap), you should see antifreeze solution (likely green). Do this only when the engine is off and cool, If you remove the black cap (engine off but it can be hot), you should see internal engine parts. 
By the way, if you haven't before opened the heat exchanger tank cap, you should check the coolant level fairly routinely (with the engine off and cool). The coolant level should be very close to the top of the tank, covering the top of the brass-colored heat exchanger tube that lies horizontally extending from the front to the rear of the tank.  There should also be coolant in the recovery tank at least to the "minimum" level. Consider changing the coolant if you don't know when it was last changed. 
Dave Hupe
1994 C320 (#32)
Perkins Perama M30 Engine