I agree with Mike B, condensation is a big problem if it's been sitting in an uncontrolled environment. Drive it until the engine is warmed up, change the oil and filter if it has one, then keep an eye on it through the summer and see if it still has milky oil.

1957 Chevrolet 5700 LCF 283 SM420 2 speed rear, 1955 IH 300U T/A, 1978 Corvette 350 auto, 1978 Yamaha DT175, 1999 Harley Davidson Softail Fat Boy