My car is smoking from the exhaust
I got my oil changed at Walmart, thr next day I realizd they put in 10w-30 when my truck only takes 5w-20 it says it right on the oil cap. When I told them, they said "they saw in the computer that it takes 5-20 but noticed the mechanic(which is part-time, once every 2 weeks) put in 10-30. He said he would flush it and put the right kind in at no cost. After we walked around in walmart for about 45 mins. we went to check, they said there was silicone on our gasket that was leaking, and because of this they couldn't touch it until I got it fixed. Now my car is leaking oil, but the dipstick says its full, it now smokes very badly when I start it, but usually stops after about a minute. This morning it didn't stop, so I couldn't drive it, for fear of breaking it. The mechanic at Walmart said that the wrong oil in there wouldn't hurt it, and after we get it fixed we can bring it back in and they will fix their mistake. Why is my car now smoking, and why didn't they notice the leak in the oil pan the day before. Am unsure of what it could be, and would like a better understanding of what is wrong, and how much it should average to fix it.
