Welcome to AF.
Possibly your lifters are the culprit, could have moisture in them from the previous coolant leak/gasket change.
I'd be asking the person(s) that worked on the LIM change.
You might be able to clear up the ticking with some Seafoam cleaner. Doesnt take much in your oil/crankcase.
http://www.seafoamsales.com/motorTuneUpTechGas.htm
Though I could also be the rocker arm or valve train, I wouldnt put it off to long, or you could damage something.
Good Luck