I always, and I do mean always, check the oil, water, and belt tension BEFORE starting the diesel. Many years ago that saved me when after spending the night at anchor with friends I checked the oil and it was higher than before! I pulled the air filter and found just what you see. We sailed her out of anchor and all the way home.

I did what you have and many years later the diesel still purrs. Oh I did the T install replacing the anti-siphon valve and have never had any problem since!