The last time I did that to one of my cars, an '80 Volare, I lost two quarts by the time I drove it off the hoist. Drove it home that way 12 miles to get more oil and it didn't hurt anything. You didn't have much of a leak if you could see the trail for many miles. It's the driving with the oil light on that is the problem. By that time the pressure had dropped to where damage is likely to occur.
I would entertain a notion to pull the pan to check the bearings. I suspect you'll find a rod bearing that is showing some copper meaning it's down to the second layer of metal. The first layer is always real soft so metal particles will embed in it rather than score the journal. There is a chance the journals are okay yet. Their surfaces are hardened. If you find one that is rough and looks dull gray, it's toast and anything you do will be a very temporary fix. If all the journals are smooth and shiny, and especially if their mating bearings are still dull gray and smooth, I'd be willing to pop new bearings in it. Do you know what "Plasti-gauge" is and how to use it? It's very inexpensive and is used to measure the clearance when you assemble the bearing caps.
Replacement bearings are available from auto parts stores that are standard, .010", .020", and.030" undersize, but if you need them, you can order.001" and.002" undersize from an engine machine shop. It is common to find tiny grooves all the way around a journal that weren't causing a problem. Those are why we have them polished when rebuilding an engine. If that's all you find, I wouldn't get too excited.
If you find any bearing that is worn so far that part of it is missing, there will be a 99 percent chance that journal is chewed up too. At that point you will need a new or reground crankshaft. On most engines now, the oil pump is driven by the shout of the crankshaft so you'll have to disassemble the timing belt to get the crank out. There is a chance you do not have to unbolt the transmission to drop the crank, but only if you can unbolt the flex plate from the torque converter and there's enough room to sneak it down. Lets worry about that if the time comes.
Keep in mind too the connecting rod bearings are the most likely to get damaged and they are the easiest to replace. They take all the pounding and they get their oil after it has gone through the main journals.
For what it's worth, I put new main and rod bearings in my '88 Grand Caravan in a misguided attempt at solving a knocking noise. That was almost ten years and 120,000 ago, and the noise is still there. I haven't bothered to try to solve it, and it gets people out of my way in parking lots. They're afraid of being hit by flying parts!
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Saturday, October 27th, 2012 AT 3:46 AM