I also have a 1998 Park Avenue, mileage 97400. Last Tue I similiar problem. On the way my car sputtered (hadn't noticed that before), and at the same time the check engine coolant light came on. When it happend I was less than 1/2 mile from work, so I went on to work and didn't think much about it, until it wouldn't start when I ready to go home. Took it to the mechanic, who replaced the plugs, it started right up and the parking lot filled with white smoke, and a bad smell - burning engine collant. They shut it off and it would not start again. 5 of 6 of the New plugs were covered in oil, gas and engine coolant.
They said then it was either the Head Gasket or Upper Intake.
Turned out ot be upper intake - we were hoping it was only the plastic seal, but it had cracked so I had to get a new one put in. We also tore up the starter trying to get it to start.
Runs fine now! Well worth getting fixed. Mine only ran me $600.
Saturday, June 30th, 2007 AT 2:54 PM