If the steam was really coming from the valve covers coolant has compromised your oil/lube circuit. Pull one valve cover and take a look. If you see a milk shake, don't run the engine any more. You may have a more serious problem. If it is clean oil, see comments above.
K
PANTERA INTERNATIONAL
A DE TOMASO CAR CLUB
Presents the De Tomaso Forums
The On-Line Meeting Place for De Tomaso Owners and Enthusiasts From Around the World
Clicking on the banner will take you to the sponsor's website.