This one has me semi stumped that I might take it in to be serviced.

I ignored this problem for a while because I've had grounding issues with my instrument panel and found certain things unreliable (oil pressure, GP light, Lamp out light)

I have installed an aftermarket oil pressure gauge.

Periodically my low oil indicator light comes on. I checked often and had plenty of oil in the engine so I figured it was a problem with the gauge pod.

The other week I had an explosion of oil onto the top of my engine which I believe came from the oil filler tube.

I do not lose oil pressure during this unauthorized engine activity, until presumably so much oil has been blown out that I have little left. I had not noticed oil on top of the engine even during previous indicator light warnings.

I've been brave enough to test drive it around town while still trying to figure this out and for a week it was good and last night I got the indicator light and some oil blowing out again. There is no pressure / vacuum from the oil filler tube or oil cap during normal running. I haven't been able to check while the indicator light is on.

My only thoughts have to do with the vacuum pump. I do have vacuum on the line. But I don't know if it drops out when this malfunction happens. Should I hook up a test gauge while driving?

Where do you think I should start? I don't think I've lost compression in any cylinders because this is only a periodic problem. However I have not tested compression recently.

TIA,
Bill

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'87 300SDL, intensely modified Greasecar setup, with nickle plated heat exchanger, 3 valve setup, 312,000 miles
'95 Suburban diesel, Greasecar basics, 16 plate heat exchanger, mercedes fuel lines, Racor filter
'85 Renault Alliance converted full electric vehicle