I have a 1991 940/B230ft with 201K miles. It leaves some oil on the driveway. I read the archives and took a close look at the areas that typically leak on a B230ft. After a serious power washing I am fairly sure that it has a leaky rear main seal. I removed and replaced the PVC breather box. I am willing to replace the rear main seal if I need to. The car is worth the effort and I plan on keeping it for the long term. I have read that using a high mileage oil or a thicker oil may help with oil leaks. What oil would you recommend. I live I western Washington State and it rarely gets cold here. If I need to I will replace the seal. The car was loved at one time. Mostly garaged, dent and rust free with a good interior, I found ipd 25mm anti sway bars under the grease. Paid $850 for the car.