Worried the mechanic overfilled the oil.

5.3 and 4.8 holds 6 qts .

Hello raygozza: My name is Roger and I will help you. Try adding 5 more qts. of oil. The 6.6 duromax holds 10 qts. of oil. thanks for using Fix Ya. Roger

5 quarts if you change the oil and filter. This should get it into the hash marks on the dipstick if not completely to the top of the marks.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

Six qts, with a new oil filter.

Hello oreo
If it's a 5.2L eng 5.0qt (4.7L)
The 4.0 takes 6qt (5.7L)
Hope this helps.

replace the oil pressure sensor

this is common on this engine don't worry about it. there is no adjustment, if u wish to try and get rid of it replace the lifters.

5 Quarts

the knock sensors are located below the intake plenum,or,upper intake manifold as some call it, they screw into the lower intake, the front one is sensor 1, the rear is sensor 2. it is wise to change both if you have some miles.since you are going to be buying a gasket set to do this job.the sensors are cheaper than the gaskets.

Most likely it's whatever sensor or sensors are used to determine that oil life calculation.