This car has over 126,000 miles on it been running good till I had number 5 coil pack code come up. I got a Coil at the local AutoZone store and new plugs since I had to remove the Plenum to get Number 5 pack out I figured I would replace the Spark plugs, Over the years of owning this car I have had to add antifreeze to it maybe a cup or so every few months looking the engine over I didn’t notice any leaks, back to the repair I replace Coil pack and plugs new plenum gasket. I started the car up ran good for about 5 seconds then it started to miss again and white steam was coming from exhaust. My question is could have I caused the head gasket to blow?