1997 Buick Park Avenue, 53,000 miles, small oil leak at the front of the engine, spread by the front 1/16th inch of the serpentine belt to spray tiny droplets into the engine compartment (passenger side). The source of the oil appears to be the vibration damper on the crankshaft. The back of the damper is dry. The front of the damper is slightly oily, the quantity of oil loss is very small. Does the vibration damper attach bolt (cap screw) seal to the crankshaft oil pressure bore? If so is the seal leak a probable cause?
Ok, to find this leak I would put oil dye in and using a black lamp locate the source of the leak. These engines are known to leak from the oil pan, front timing cover area and the oil sending units. The best and surest way to find the leak is to add dye, drive the car for a week if possible and put on a lift while running the engine at 1000-1500 RPM. This should force the oil from the leaking source.
The oil pan is dry. I dont know where the sending unit is located. The timing cover area is dry. The only real oily place seems to be the front of the vibration damper. Since the oil gets thrown all over the engine compartment on the passenger side it seems the dye would be thrown also. Is this correct, does the dye penetrate the oil? The inside of the damper is dry, the oil pan is dry, so I was tentatively ruling out a front main bearing seal. But I dont know if the bolt mounting the damper to the crank shaft has a seal to hold oil pressure. That seems to be where the oil is coming from. Do you have any engine assembly books that might clear that up for me? Where is the oil sender?
Yes the dye mixes with the engine oil and comes out where the oil leak is. The engine oil sending unit is located above the oil filter on the right rear of the engine. Here is what I have for diagrams for that engine ok. I still think the dye is your best bet for finding the leak and if the oil pan and timing cover look dry suspect the front main oil seal around the crank seal.