1992 22re 4x4 pickup

Around town, my truck doesn't leak a single drop on the pavement. I've done a few 50+ mile trips in the past 12 months or so and noticed that it leaks quite a bit. I just recently drove 70 miles and had to add between 1/4-1/2 quart when I got to my destination.

It is coming from the front of the motor, but is hard to tell specifically because my motor is very oily. I have changed the PCV valve, but that made no difference.

 

Then clean it. Spray-on degreaser and a garden hose work well for me (keep it away from the distributor and other electronics). If the motor is "very" oily you may need to brush it too.

Finding an oil leak on an engine already covered in oil is VERY difficult. Once the engine is clean you'll be able to find the leak in a few minutes.

 

All that oil and dirt helps to seal in and absorb your leak as well. Can explain why you only see it on long drives as it takes that long to soften that mess up and allow the drip.

Second the cleaning. Then it will show quickly