I had intake manif gasket & valve cover gask.replaced. Drove away and temp on 1993 GMC Vandura 2500

Went up pulled over then waited for temp. to go back to middle went back to mechanic. Now the oil looks black in am then looks normal when checking it. the oil pressure gauge goes high low when stopping. Still see some leak where mechanic said these gaskets need to be done. Now what do I need?? has 215505 miles. Thanks

Asked by for the 1993 GMC Vandura 2500