Yes, if it's milkshake when cold, it has a problem. Just remember, this engine has milkshake just after starting, until full warm up.No worries! So replace the collars at the hose, and check the fuel level then potentially pull the carbs. What is the head gasket check? I can check the oil in the site glass, to see if it is a milkshake color...
Not running, water/oil will settle out and separate, so might have to drain it to see.