is there any way
23-F could of turned into a civil war?
No.
Even IOTL, where the coup suffered from a bad coordination (one of the reasons for the 1936 coup turning into a civil war) nobody would have risked to start an event that was universally feared since the francoist system turned insustainable, and that was contrary to the Western bloc's interests. There is the issue of the king turning against the coup, but I suspect this was due to its lack of coordination and not vice versa.
In short, it is reasonable enough to think that the coup could have succeed, but it deriving to a second civil war is near ASB, I fear.