[P-51 Mustang]

I have a 1998 Boxster which I just put an aftermarket exhaust manifold on. To get the driver side on I had to pull out the thermostat. After getting the entire thing back together I cranked it up and let it run for a bit. Then I noticed a small drip coming from the thermostat housing. What does Porsche use for a gasket here; a simple silicone bead or an actual gasket? Also I noticed when I start to accelerate there is a soft ticking noise that comes from the driver side of the engine compartment. Could it be I need an oil change (it is extremely cold outside, like 25 F, and I have mobil 1 full synthetic 10w-40 in the car) causing the hydraulic lifters not to get proper oil flow? Or is there another explanation? Thanks!!!