Yes, the leak you are experiencing is probably from the pressure sender switch and/or the temp sender. It could be either, but I believe that the pressure switch is much cheaper than the temp sender. Even though the temp sender is completely sealed from the oil, there may be a small crack in the protruding brass part. It will leak. Unplug the two connectors and clean them well. Clean the switches and the surrounding area. Use brake cleaner or carb cleaner. Start the car with the hood up and watch the switch bodies. It should only take about 20 seconds or so to see if there is oil coming from either or both of the switch bodies. If you're not sure, shut the engine off and swab each switch individually with a Q-tip.

There are also two lines where the oil filer housing connects to the oil cooler. Clean around these fittings and watch them also for leaks. These are _usually_ very reliable. If one is leaking, you can get by for a short while by cracking the offending fitting open and retightening. They are very tight! Get new sealing washers for these if you ever take them apart or if they leak.

Those switches can leak badly enough to spew a whole quart after 300 miles. I've only seen the fittings leak a tiny amount.

James Muskopf
1975 530i/3.4L Motronic

jmuskop_at_vt.edu