When a/c was on, steam from under hood and a/c went warm on a hot day and on another day came out cool for a several minutes, then went warm again
My car has 108000 miles.
My car has an automatic transmission.
The source of the steam should be the first thing repaired. It is highly probable that once the leak is repaired, the A/C system will begin to work again. There are two fluid sources under the hood that can create steam. They would be coolant and A/C refrigerant. The description you have given suggests the refrigerant is low in the A/C system and this is also consistent with the steam from under the hood. In addition, if you had a coolant leak, your car would most likely be overheating and the leak would be getting worse the more you drive it. It’s is very rare for a cooling system to leak and then stop. The A/C system however under goes a series of pressure changes as it begins to produce cold air that could easily create a leak and then turn off as a result of the sudden pressure drop.
I recommend the following inspection to help you out; AC is not working inspection, to get your air conditioning system back working again.