I have one that sits on the oil fill tube on my wagon. In the cold weather the moisture forms on the inside of it.
That's way Crawfords can has a coolant hose going to it to keep it warm.
I won't do this again.
174,000+ miles, 5/20/12 new ej257 short block, 8/20/11 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. Also CHECK YOUR OIL, these cars use it.