My car has 99,500 miles and seems to sweat oil somewhere around the block. I looked under the car but cannot see the actual leak. It also drips on the ground. When it accumulates after a couple of days it drips on the exhaust causing an odor. It uses about 1 qt every 3-4K miles, seems normal. Is there any fix for this leak?
There is a fix but some require that the engine or transaxle be removed from the car. Use the search feature of the board "oil leak" , "oil filter adapter" and you will get lots of fun reading.
The oil leak seems to be around the crank case. I know this is a stretch but are there any additives that can reduce the problem?
First do a little homework. Get under the car and wipe off all of the oil that you can. Then use spray brake cleaner to go over it one more time.
Check the oil filter for tightness.
Drive for a day then get under the car and carefully look for any oil leaks. Track it/them back to the orgin.
The oil filter adapter O-rings can shrink causing a leak to dribble down from above the oil filter.
Remove and replace the O-rings
The oil cooler lines can leak, again usually the O-rings have shruken enough to seep oil.
Check the oil cooler lines where they enter the radiator, same solution as above.
Oil pan bolts loose. I use a 1/4" drive ratchet, with a flex 10 mm socket on it, these to avoid overtightening these bolts. The oil pan seals on a silicone gasket and over tightening won't help, you will just strip the bolt hole.
Just make them good and snug.
For extra credit remove each oil pan bolt, spray brake clean the bolt hole and bolt, allow to dry, put pipe dope on bolt and replace it.
Do all bolts and allow to set for at least 24 hours before running the engine.
If nothing else these suggested procedures should reduce any seepage that you have.