Q: There is a blow off valve type sound coming from the engine and then steam coming out.

Let me address your mention of the A/C first because of the possibility of a refrigerant leak. Such leaks do create "steam clouds" like that you are describing but the leaks end VERY quickly because the refrigerant boils off violently as it hits the atmosphere. At any rate, IF the A/C system continued to blow cold air during this incident, that would mean that the A/C system is NOT the source of the leak.

If the A/C system did not develop a sudden leak, the likely explanation for the steam cloud is a cooling system leak. Such a leak can be addressed during a mobile visit from YourMechanic. You report an additional issue, though, which is the no-start condition. YourMechanic can diagnoses and repair that as well. Your no start condition could be due to a simple problem such as an old dead battery in need of replacement. If you want to do some initial work of your own, on the no start problem, just fully charge the battery, and once fully charged perform a load test on the battery to see if it is any good. Please let us know how we can assist you further on these two problems that you are having with your car.