He ran the car very hot
could have compromised the engine
8 is a end cylinder
leastr on mine
the gasket could be a result
or it could have precipitated the drop in coolant therby raising the engine temp
further increasing the gasket damage.
Gasket should have been in pretty good condiiton
considering it had or should have been replaced when they did the timing chain.
Perhhaps that gasket has been a problem since the job????
Car had only had 2000 miles since the job
Most likely the overheating is a symptom not a cause
Knocking well...I won;t guess
as I never stayed in a Holiday Inn...
Good Luck
I know how frusstrating it can be