I have had such a good experience getting my 300 SD back in shape here on the forum that I would like to throw out this problem with my Rabbit diesel pickup. It is an 83 with the 1.6 engine. Recently replaced the head gasket and since have had this problem. When starting up after sitting overnight the oil pressure sits at ZERO for about a minute. Then it will build up to sometimes over 100 PSI{cold temperature} then as it warms up will go back to 30-50 PSI. When the pressure is down I let it idle until it gains pressure but I am fearful that the bearings will suffer eventually. Anyone?? your input would be greatly appreciated Willie(Poor Soul}