I have a Citroen Spacetourer van with the BlueHDI 150 engine, bought new two years ago (in 2017). The prescribed oil change interval is the same as regular maintenance interval, which is every 2 years or every 40.000 km, whichever comes first. I've just got the van back from the first round of regular maintenance and oil change.
It's the long interval that bothers me - all cars I've ever had had much shorter oil change intervals - like 10 to 15 thousand kilometers but never longer than a year apart. I've been told countless times that the time interval is as important as the clocked kilometers and never to exceed the year because the oil fouls with time as well.
Do I need to worry about the long oil change interval? I'd appreciate an answer from someone who understands the reasoning behind this or works with HDI engines but I welcome well founded general answers as well.
Some details, although I don't know which are important for oil change intervals and which not:
The van is about two metric tons empty and usually drives with only people on board. Sometimes, for about 2 to 4 thousand kilometers per oil change I tow a transport trailer or a camper trailer, both between 1 and 1,5 metric tons.
I drive moderately, neither aggressively nor economically. My consumption is 6,5 l/ 100 km on average (some 36 mpg) and I don't see much tire or brake disk wear to signify excessive energy dissipation by the van.
The van's on board computer told me to go to the maintenance a bit early, at about 38.500 km. I couldn't find any explanation in the handbook, though, so i can't say whether the engine control unit monitors cold starts etc and calls for maintenance accordingly. I forgot to ask about it at the dealership.
The dealership told me that the replacement oil with required properties is available from one manufacturer only (Total) and that I'm strongly advised not to use any non-recommended oil for prolonged periods of time.
In the first 40 thousand there seems to be no oil gone, the level remained perfectly in the middle of required range for the whole time.
I want to keep the van for 200 to 300 thousand km and 10 to 15 years, then sell it for whatever price it sells (i.e. not aiming at a good sale after I'm done using it).
I almost always deactivate the stop-start system (I don't do it only when I forget to) mainly to avoid weird accidents and almost-accidents it always tries to cause and to avoid excessive wear on the starter and bearings, I haven't given much thought to the question how this affects the health of the oil.
I don't want to change the oil myself just in case as I'm not equipped to do it and can't dispose of the used oil in a civilized manner. Nearest dealership is 100 km away and they are usually fully booked for two to three weeks. This makes the longer interval convenient.