The HDI is a very solid engine, and I don't share Spyros' opinion on the electrical circuit... Yes you need to know what you are working at, but these engines are easy to tune, very inexpensive and can be found easy used... also parts are very easy to pick up at breakers.
I guess to have 320Nm/140BHP that should be good for 200,000km without much attention.
For 140 Pk and reliability you need to think about a 2.2 HDI.
But, have you heard about the damper puley issue ?
Have you heard about the "special clutch" ?
Have you heard about the EGR valve that is far from simple to disconnect without generating another electric alarm that will lock the engine. ?
Have you seen the tar that you can remove from this EGR valve that will strangle your admission ?
Have you heard about these marvlous exhaust that rust and snap at the welding (impossible to repair)
Did you think that even the 110 pk engines needs a heat exchanger and that a heat exchanger need a lot of fresh air that you will NOT get in the engine bay ?
Did you see that the good breakers will try to get ALL the peripherics up to the contact key because when this is not recognized you get plenty of electrical issues ?
Have you heard about the fact that some of them have a very very problematic Siemens fule pump (Bosch is no issue) ?
Did you hear about all the HDI who stops because of a bad electrical contact "somewhere" ..
Or Lock themselves in "safe" mode, so that you can drive at 1500 rpm maximum
Or do it when the engine is at temperature ?
Have you heard people being told that there is "a problem" with the injectors and that all the system needs to be replaced at a cost more expensive than their car value ?µ
Have you heard about new precharge pump that don't provide enough presure ?
There a LOTS of issues with these engines and 200.000 km without much attention, forget about it. Never !
When with the 1300 , 1440 , 1590 cc Matra engine, 300.000 km are possible, most of these HDI don't get to that milleage.
Last issues in February this year : Engine stop while driving. Not able to diagnose the possible cause, several Citroen diagnostics. The only wrong thing discovered was a pre heating plugs control box. Can you tell me what this could have to do when you have the issue when driving ?
Box replaced (and only that) and the issue disappeared.
... for 10.000 km and comes back (or another one)
Then only thing done : replacing the still good battery by a better one, new.
And ... the issue is gone again.
What could be the battery impact on a diesel engine running
And when the alternator is delivering corrctly ?
Is that what you are thinking reliable ?
I'm living with this engine every day and I can tell you that at 200.000 Km, you just think about throwing it away. And this with the standard untuned power. I got before that a XUD 11 ATE and at 300.000 km, I was far from thinking the same