FYI on the dipstick... It did actually push the dipstick out of the tube.

I don't know of a thermostat for the oil cooler. I don't see where it would be, but don't doubt that there would be one. I do not believe I have a leak from the oil cooler hoses, could be wrong. Hard to tell. The IP oil leak puddles in an arm/motor mount.

I checked the vent tube from the valve cover to the air cleaner and it is clear. Not sure where else to check in the crankcase ventilation system as this is the only part I'm aware of!

In any case I took a look at the oil filter and the upper portion had noticeably collapsed. I'm not sure if this is normally the case as a filter gets used that what is closest to the riser tube (um, lacking proper terms here) morphs from a nice round internal part to a bunch of wet newspaper. The filter is not old at all, but maybe I got a bum one? In any case I changed it and will drive the car tomorrow and see what we get.

On the chance that it is the filter I'm assuming that oil was being pumped up to the top of the filter but could not go any further???? I guess perhaps even the bypass would be clogged??? Haven't spent the time to figure out exactly how that setup works. It looks the same as the 70's 300D oil filters.

I will report findings back. If anyone has any ideas on where to stick some test gauges in the meantime I'm open to thoughts... like vacuum gauge on the main vacuum line, etc., etc.

Thanks again,
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