I don’t see a dip stick to check the oil on my ’25 Series 80. How do I check the oil level?
On the passenger side of the oil pan there is a stopcock.
Open the stopcock and if oil comes out, the engine has at least sufficient oil.
If not, then add oil until oil comes out of the stopcock.
Do not mistake that SIDE stopcock for the DRAIN stopcock, which resides at the bottom right of the oil pan.
I believe that the Series 80 engine takes about 9-quarts of oil.
A bit more is fine.
Use Diesel Grade oil.
When checking the oil, make sure the a small stream flows. A few drops may just be oil standing in the petcock which can give a false indication.
Unless you are sure that the oil passages in the engine are clear of any sludge do not use a detergent oil. I was using detergent oil in a Pierce-Arrow engine that had sludge in the oil passages of the crankshaft. The detergent oil freed up the sludge. The result was a plugged oil passage which caused a connecting rod bearing to fail.