Diesel engine oil becomes acidic very quickly. There are no or few provisions for that neutralization. Manufacturers rely on strict oil change intervals. That's why diesel motor oil is not a good solution for older motors,ZPPD. Granted, gas engine produce acid from the combustion process but not as quickly as diesel. Just get a new factory pan clean the inside with acetone, water based degreaser, acetone again scuff 80 grit and use GE Glyptal. Should solve this problem.