Can only tell you the various problems we had with our D3's. Horribly put together engines and apologies for the rant below but best if you know what we found with D3's.
1) If you have an outdrive a faulty trim sender unit may put the engine into safe mode. We and multiple others I know had multiple instances of that. Volvo may have changed the software around that problem in later models. Ours were early generation ones. After replacing 3 of those sender units in around 18 months from new at ~$600 per unit fitted, and having numerous trips ruined by false 'safemode' activation I had a very intense argument with Volvo about the crap product and what they should do about sorting it out. They more or less laughed in my face so I just started telling the world very loudly about Volvo D3's (lots of other isues also). Then they threatened to try and take me to court for defamation for publishing the problems. I said go for it. The extra publicity about your products will be awesome and save me a lot of work trying to stop someone dying when the next engine needlessly fails. One of the other owners I talked to left his failed again boat at an offshore island, flew his family back, then walked into the Volvo dealer, told them where the boat was and said "you go get it".
2) The variable vane turbos can be highly problematic. After replacing one at some crazy cost I got good at stripping and cleaning them. The vanes stick and you can get either underboost or overboost which I think is why some D3's have grenaded. I showed one I had removed to a very large turbo spe******t when trying to sort out a problem. His response was "you saying they put these things in boats!!!". Anyway, he told me what to look for when stripping one to service it. Volvo just tell you that they are 'unserviceable' and try to sell you a very expensive new one.
3) We had issues with a bad crank angle sensor that varied between safe mode and not starting from memory
4) Some early models at least had significant issues with the wiring connectors to the ECU box. Our didn't, but others had big issues
Other than those possible safe mode issues we and numerous others had issues with the main coolant hoses rubbing on metal brackets etc and almost sinking the boat with quite low use. I guess they corrected that in later models but worth a careful check of your water hoses anyway. At the time we found our rubbing hoses they were just about to start leaking and sink the boat. Discuss with Volvo as it was an obvious build issue not an installation issue. They tried to deny responsibility but eventually supplied replacement hoses which of course rubbed in the same places when fitted to spec. We had to manually alter the hoses when we fitted them. Quite an argument with Volvo about that. A few weeks later I warn a friend with the same engines to check his hoses. His boat is close to sinking as well. Talks to Volvo about new hoses getting fitted and the reply is "Never seen that before". They didn't know that I had talked to him obviously. See another boat with the same engines and talk to the owner. Same problem and he gets the same reply - "Never seen that before".
Did you also know that Volvo say you can't rebuild those engines? We got told when we had to get the Volvo mechanic down to run the Volvo only diagnostic tool over them that our sub 1000hr engines were worn out and needed replacing. That was rubbish, but I don't think you should expect a long life span from them based on what I learned.
As a final note, it appears that the D3 was/is made in multiple factories. I was told Sweden and Mexico but can't confirm that. What I can confirm is that when we went to fit the new water hoses they only fitted on one of our 'matched pair' of engines because the metal fittings they went on on one engine were so different in size to the other engine. Either some horrific issues with quality control from one factory or two different factories with poor quality control between them as was suggested to me.
