If you can catch it early enough, fit a shaved down copper washer (as a spacer/shim) under the smog pump clutch. It is an electromagnet actuated clutch and mine dragged on the pulley until it was too late to save the bearing, grease got cooked out from the excessive heat. A wee bit noisier when it kicks in and out now (louder click) but no more clutch dragging on the freewheeling pulley.

While I'm here, help please. After searching here, I still can't locate the fuel pump relay. General area I found to look was behind and to the right of the battery. The only thing there is the fault code/reset box. This is a '91 300SE that has been down for a year but was started and run to operating temp regularly. It was running fine until the other day when I left the key on while dealing with a sunroof issue, now no noise from the fuel pump. It will spin over just fine but with no fuel getting up front........