I feel your pain. Trying to get an honest and correct evaluation is very diffult.
In summer 2015 while in CO, I began getting check engine code, crankcase over pressure. Only happened going downhill. Freightliner said change the crankcase filter. Drove back to New Orleans, no issues. Replaced filter Jan 2016. Drove to Mexico Feb 2017, CA and back to New Orleans, no issues.
In summer 2018 drove to SC for service at FOCC service center, began getting codes again. After service they said to go to Cummins in Spartanberg.
This is where it gets interesting. They spent a day with the engine and said they THOUGHT it was due to broken rings. They would remove/inspect/replace engine for $9K. If nothing was found to be broken extended warranty would not cover cost. My engine was not rebuildabe. New engine was $18k, 30 days to build.
We were on our way to KY to start work at Amazon. We drove to KY and sat till I was done working Dec 19. Drove back to New Orleans. As long as I kept RPMs below 2100 no problems.
Took coach in to NO Cummins, they sent me a pic of the turbo and said it was dusted. Of course warranty would not cover. They did not have the facilities to drop engine, so referred me to S&H Auto/Truck service in Hammond, LA.
Gave it to them and said fix, either I was going to pay or estended warranty was going to pay. Either way it had to be fixed.
Bottom line, all top rings were broken. New engine not available. They got a long block from Jasper. New injectors, injector pump and turbo, all else transferred from my engine.
Total cost $37+K, I paid $3.5K. My extended warrany expired in Mar 2019. Was a hard road, but they paid.
Good luck.
Dan & Sharon (Kasey, Our Yorkie, RIP 9Jan'05-26Jul'17)
2012 Winnebago Journey 36M
2020 Chevy Equinox, Blue Ox Aventa II, Air Force One
If You Obey All The Rules, You Miss All The Fun