If you are seeing oil on the cooler lines replace them ASAP. Could also be where your oil is going. As the car heats up the thermostat opens and lets oil flow to the cooler under very high pressure. You will not see much of a leak if any at all at idle or when the car is cold. I had a tiny hole open up a couple of years ago on a trip back from KY and lost 4 qts in 300 miles of highway driving.

I know some guys who have oil usage problems for different reasons but they are using the "house Brand " Walmart oil. I know.......but it is CI-4 rated, cheap and probably made by chevron or shell anyway. Anybody know who makes it for them?
Anyway it's the rating thats important not the name.

Stephen

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85 300D 305K miles WVO(105K so far), Mine
82 300SD 235K miles BIO-D, Wifes
96 F250 SC PSD 4X4 285K MILES BIO-D, Ours
89 BRONCO 182K MILES sold
Finally Compression Ignition Only!