I had a leak on one or two valve covers so figured I would change all gaskets. Did that, torqued the nuts to 18 ft-lb like page 9-16 of the 1991 service manual supplement on the diesel engine said. Next time I looked under the hood it looked like all the covers were leaking. Anyone ever have that happen to them? How did you fix it? I thought I knew why the old gakets were leaking, there was gunk under the sealing surfaces. I was careful to clean the surfaces. Gaskets came from Carquest and looked as good as the ones I took out. Is 18 ft-lb the proper torque? Should I retorque them when the engine is hot? Any suggestions would be welcome.