general problems of the 1997 Cadillac Eldorado

Have had two Cadillac el dorado's. Both of which have problems with the trunk leaking. Have had to drill holes in the bottom of our first Cadillac to allow the water to drain. Have also had to use a shop and vac to suck out the water. Thought it was a problem with the older Cadillac's. However, a year ago, purchased a 1997 Cadillac el dorado and have had the same problem although not to the same extent. The wetness in the trunk is causing condensation and mildew. The odor comes into the car.