X15 Engine

[Cumminx15]

I have a Cummins x15 engine 424k on miles

When I’m driving and let go of the gas the turbo makes the spooling noise and it feels like the engine brake is on and it slows down but my engine brake is off

When the truck is idling 600rpm the engine is real shaky the power steering reservoir shakes like crazy but they I take the idle up to 700-750 rpm the shaking stops

I suspect I have a coolant leak somewhere
They discover green moisture on my valve cover and I saw green moisture inside the walls area the mechanic said it could be condensation
Where the engine oil tube is inside is wet water
Coolant is getting low after I drained all of the coolant so I had to top it off to cold max level in the morning but I cold start my truck once a week haven’t drove it in weeks it’s still down to minimum cold don’t know if that’s normal

Valve adjustment was done on my truck and the guy screw up didn’t do it correctly valve cover gasket starting leaking bad had to do it again and took it to a different mechanic they discovered one valve was really loose so they said they fixed it but the guy did it so fast I don’t think he knew the measurements on my Cummins x15 I saw they have the measurements on the engine cover but I’m still having this ticking noise I have to re check it for the third time.

I want to pull the abuse history on my truck and have someone take a look at it