Reed mentions one of his first lessons: "Let your partner know what you're doing." The statement may refer to Malloy chastising Reed in Log 1: The Impossible Mission (1968) when Reed didn't follow Malloy's orders in the dark park and went off and did what he thought himself was right without telling Malloy.
When Sgt. MacDonald arrives at the car explosion, he's driving a sedan - not his assigned station wagon. Sgt's didn't always drive the station wagon. The wagon's carried spare/extra equipment for incidents so were used for that purpose most often.
The 1955 Chevy used in the "459 silent at the warehouse" scene was also used prominently in Two-Lane Blacktop (1971) starring James Taylor, better known for his singing career, and in American Graffiti (1973).
Code 2 = urgent, no lights or siren.
Shirley Young's car appears to be a Hillman Minx.