That is an old engine likely with a lot of piston and valve guide wear resulting in blowby. Probably worth rebuilding by a competent shop if all the parts are still available, no replacement on the market.

an HH-60 is a cast iron work horse .....you have several options .....compression test ....leak down test (looking for blowby)....and I would suggest replacing the valve cover crankcase breather first ....it maybe defective causing the situation at hand .....does your engine have a dipstick? if it does ,be sure you check the oil level with the engine level ,not at an angle......Jim