Not unlike the other owners that complain about the water leak in the intake, mine did it too, but I had the gaskets replaced by an independent shop for 250 dollars. That took care of the coolant leak, but about six month later my son pulled in to the parking lot at his college, parked the car, was running fine. He restarted it about 3 hours later and it was knocking loud. We had to find a used 3.1 engine to replace it as we were told it had bottom end damage. So we find another one with just 90 K on it, and replace it. Well the replacement included of course an intake gasket before it went in. Then to our surprise six months later he had the same thing happen again, parked the car running fine, started it a bit later to have it knocking like crazy again. We have given up on the car now, sending it to the junk yard. I am not sure of the cause of the engine failures. We use Castrol Synthetic Blend oill and change it every 3000 miles so not a maintenance problem. The coolant was full, just something coming apart in these engines. It knocks and runs rough , like it dropped a valve or something of that sort.