'52 331 Factory oil filter doesn't drain

[Jim Salmi #21340]

When changing the oil on my '52, I found that the oil filter canister did not drain.  I had to use a syringe to remove the oil (almost a full quart).  I assume it was designed to drain and that the lower line is plugged, and that I will have to remove the canister and the steel lines and clean them with solvent.  The lines appear very small, maybe 1/8".  That seems like an invitation to plugging up.  It that the correct size?  Should I consider putting larger lines?

Thanks in advance for any thoughts.

Jim Salmi

[Jeff Maltby 4194]

Your cannister doesn't have a drain plug on the bottom side ?

[Jim Salmi #21340]

I'll have to look.  I didn't feel one, but it didn't occur to me that there might be one.  When the oil was customarily changed, did the dealer have to undo this plug?  Seems kind of messy.  The shop manual is silent on the subject of oil changes.

[Jeff Maltby 4194]

I image they did but I use a baster to remove the oil. The oil remains in the cannister after filter removal as designed and was never intended to drain via the lower tube back into the block if that's what your asking ? 

[Dave Shepherd]

Same thing here with the baster, remember this is a by pass filter sytem and there is only partial flow to the filter.

[Otto Skorzeny]

Yes. The oil should be sucked out with a hand pump or baster.

My '56 has no drain plug.

[Jim Salmi #21340]

Yup, that's what I used- a turkey baster.  But, wouldn't gravity alone cause the oil to drain back down the lower line, assuming there isn't a check valve?  I'm curious as to why Cadillac would have designed a system that would be intentionally messy.  Unless, of course, we all are using basters because we all have plugged up lines.  That doesn't seem too likely, either.  I should just quit intellectualizing and clean the thing, I guess.

Thanks for the input, guys. 

[joe12138]

There is nothing wrong with the filter cannister, and the line is probably not plugged either. If the line WAS plugged, there would be oil seepage at the ring gasket for the lid. The oil pressure, low as it is, is enough to push oil through the media and through the return tube. As far as the design of the unit, it's so simple it's clever. The oil enters around the outside of the filter. While it's waiting to piddle it's way through, gunk, worn bearing metal, and the "big stuff" settle out into the bottom of the housing BEFORE they even have to deal with getting through the filter. This even happens with the residual oil left in the cannister from your last trip, even after you walk away from the car.      AFTER the oil passes through the filter media, it exits through the tube that returns it to the engine. But to enter the vertical tube, it has to pass through a horizontally drilled hole to get there.That hole is NOT drilled near the bottom, but about an inch and a half, maybe 2"  or so higher than the bottom of the filter assembly....so that that settled-out junk doesn't find its way back into the return oil when the cartridge is pulled out.
   The drilled hole is pretty small, but it acts as a metering device to slow the flow enough that you don't lose oil pressure to the drivers side rocker assembly. The return tube, as you say, seems small. But it's a lot larger than the drilled hole that feeds the oil return, so it allows the oil to return to the engine just fine.
On a high mileage or car that had just oil changes without anybody actually cleaning out the bottom of cannister with a rag or baster, you'll find a thick, silvery sludge that feels and looks like Never-Sieze. That' the remains of normal bearing wear over time and miles. Not to worry......this simple filter kept tha junk from ever getting to the oil pan to get recirculated.
At first blush the filter setup loks simple and ineffective...but it works well!