No way GM was going to overcome the lack of head bolts on the 5.7 Diesel. Further the "new" single use TTY head bolts made repairs useless as no one esp. GM dealer mechanics had ever seen a disposable head bolt before. Manuals and training were not so good back then.
The 4.3L V6 Olds Diesel was a different story. Not sure the 1985 FWD version with aluminum heads would have had better service with the expansion rate difference taken out on the head gaskets. At least the V6 had enough head bolts. Sadly the FWD V6 GM donated to the college I went too had an occlusion in a piston from bad casting that would likely have shattered it eventually. I was the only one who touched it in the engine class since GM had donated it for educational use only. And due to odd lab class size I went it alone without a partner. (They scrapped the engine after that.)
It is one of the most inefficient Diesels out there. If it ran long enough. Other Diesels were out there that could go the distance and deliver even better MPG. GM chose poorly because CHEAP (and no longer having car guys in leadership at the time). Compared to the gasoline engines suddenly strangled by emissions and Unleaded vapor lock prone Gasoline of the era, yeah, they delivered better MPG.
Dad took a oil sample on our 1980 Delta 88. After it broke the alternator bracket under warranty. The oil lab called it was so bad. After they figured out it was a Olds 5.7 Diesel "Oh, they are all like that." Dad didn't keep the smoking underpowered Olds after that. I still recall people coming out of the smoke cloud waving their hands in front of their faces behind us somewhere on a grade to go see Mount Rushmore.
Without addressing the common in the day gasohol used to remove water that ruined the governor flex ring, lack of good fuel filters, and water separators the engine would still be a non-running lawn ornament. Our dirty wet Diesel fuel is just that. Even now ULSD lacking lube for the CP4... Seriously GM had to do a recall to add a Water In Fuel Light. Wow GM owned Detroit Diesel and missed this. (From the 6.2 GM history: GM wouldn't have listened anyway.)
It was typical GM to come: experimental engines turned loose on their customers for R&D. You could have purchased another disaster Cadillac V8-6-4 ... or any Cadillac/Oldsmobile engine of the era that also had camshaft flat lobe trouble let alone the WTF mechanic blank stares from the constant changes on emissions systems during the model year including the coil in burned through distributor cap HEI "mystery".
Regardless the Olds 5.7 Diesel is deservedly the most hated engine in history for what it did to the North American Diesel market.
I can only share my experience with them and I have to say I’ve never had any major problems with those in 25yrs of driving them.By using arp fasteners in critical areas they can be made to last.
They only have a short stroke configuration so they are certainly no powerhouse but I think the design was rushed into production way too early in trying to compete with Mercedes Benz at the time.
GM always did cut corners to keep costs down.Imagine how great the 6.2 and 6.5 would have been if forged cranks and bedplates were in place.It would have been a different ballgame.Of course that would increase costs by a fair margin.
Head bolts were commonly reused on the olds and stretched bigtime.Lack of Headbolts per cylinder didn’t help either.I’ve been around them quite a long time but with a few improvements such as better fasteners and a good water separator they can be decent power plants for what they were designed for.