I was reading on your site about a fellow who was experiencing a problem with his 1999 Jeep Cherokee. I am experiencing the same problem (all the way down to the speed at which he experiences the noise – 65-70 mph). I wanted to follow up to see if he ever got back in touch with you to let you know how/if he resolved the problem.
I have an old Honda Accord, 1999 standard EX model. It’s had a problem with oil for a number of years and no one seems to be able to find the cause.It’s not burning it, no blue smoke under load or when revving the engine, and no white tail pipe. There are no drip spots under the car when parked. It seems to be most noticeable with highway driving however this could be due to the amount of time the engine is actually running as opposed the strain on the engine. The amount of oil is significant, up to 4 liters per 1000 km.