The disappointment with the 5.7L Olds diesel was the damage done by the first generation clouded perception of the second generation. The first suffering from severe lifter and cam lobe wear from oil contamination. Owners did not realize the importance of the 3000 mile oil change with the diesels compared to lazier practices with gasoline engines. The EGR system in the diesel pumped a lot of soot back into the crankcase as blow-by. Additionally, the lack of a water separator contributed heavily to those blown head gasket situations as well as injector pump corrosion.
I had a 1981 Bonneville with the second generation 5.7L diesel and had no problems except for a fuel gel-over during the big chill in 1983 until about 70,000 miles. One of my GMI classmates worked on the V-6 diesel development at Oldsmobile and and gave me a few tips on the 5.7L for reliability. The roller lifters in that engine cured the cam wear and a water separator had been added in the fuel filter. My problem was worn out wrist pin bushings leading to piston slap and three bent rods.
I found a specialist in OKC that rebuilt them with drilled rods to pressure feed the wrist pin bushing, and he changed the head bolts to the larger diameter ones from the 6.2L diesel. He essentially blueprinted the engine and you could definitely tell the difference with the ease of starting and performance gains. I went another 200,000 miles on the engine before a Texas hailstorm totaled out the car. I never got less than 22 mpg with that car and went as high as 34 mpg on the highway.
My biggest complaint was the wimpy Turbo 200N transmission they used. I went through 4 rebuilds due to lock-up torque converter failures. The diesel had too much torque at low rpms before the transmission oil pump pressure was high enough to maintain the lock-up in the converter.
Still the best long distance cruiser I ever had though.
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