Performed pm on oil boiler Brushed and vacuumed flue pipe and heat exchanger Replaced oil filter, nozzle, and strainer Checked all electrical connections and safeties Performed combustion and smoke tests 4l0%o2 19ppm co 0 smoke While performing the maintenance we found the combustion chamber is beginning to crack and the bottom blanket section is missing pieces. Brought the customer down and showed them the cracks. Also found the oil pump shaft and seal are beginning to leak. Found high amount of oil from the leak inside the burner air band where the pump mounts. Brought the customer down and showed them the leak. After getting customer authorization we replaced the oil pump. Recommend replacing the chamber in the future.