Report "I run out of hotwater 3 mins into a shower. The water heater looks old. The tank feels warm at the top and bottom. A friend of mine told me the lower stat was bad so I replaced it but the problem continues. I just bought the house the previous owner ran all new plumbing (pex tube)but im not sure he knew much about plumbing. Could that be the problem or should i just replace the water heater"