Post-winter oil leak from crankcase?

In preparation for several months of below zero weather, I stored my 84 cab in my unheated garage, meaning to start it every week or so throughout the winter. It got so cold that I have been afraid to start it. Then another problem surfaced.

When I parked it, it had very little oil leakage. I last started it in November when it was probably a little below freezing and it had sat for a couple of weeks. A few days later I noticed a pool of oil the size of Texas forming under the engine.

Now that it's warmed up a bit, I took a long time to look for the leak. It does not appear to be coming from any of the oil return tubes, and seems to be dripping straight out of what I believe is the crank case - the largest and lowest solid metal object directly below the engine.

I have a three part question. First, does it sound like I blow a seal or gasket by starting it in the cold without putting winter-weight oil in? Second, is a gasket in the crankcase housing a likely culprit, or is it more likely that the oil is leaking from somewhere else? Finally, how difficult or expensive is it to fix the likely causes for a leak like this?

I'm now almost one year into 911 ownership. I have been assuring my wife that I'm on the upswing of the learning curve.

Thanks, Mike

I think you're gonna need a lot more investigation to find the source of the leak.
Just about all leaks end up *looking* like they are coming out from the center crankcase seam (although that is rarely the real source).
One likely culprit is the oil pressure sender switch on the top of the case. There are lots of posts/treads on this topic, try doing a search.
That would be a best case scenario, a $5 part and pretty easy to replace (20 minutes for someone who has done it before).
But it could be any number of things, someone is gonna have to just clean things up and pinpoint the leak.

Thanks, Jim. That is exactly where the leak seems to be coming from. The temp is supposed to be in the high 60s this weekend. If it does warm up I will run it over to a car wash where I can use a wand and clean the bottom and wait for the drips to start.


Mike

I dont think it is your oil pressure switch because it is at the top and the car needs to have been running in order to leak after the car had been turned off "pressure"
When you move the car first look at the area where the trany and engine meet there is a hole at the bottom of the case on the motor side and if your main seal went you will see or feal alot of oil there. If you have to repair this seal you have to drop the motor and trany, this is not very difficult and there is a lot information on the board.
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