[glend]

Only if:

it had a Provent installed from new,
I knew its history and had seen the service records,
and had a good diesel mechanic go over it.

The engine itself will probaby be ok if serviced as recommended by the owners manual, the problems come from the auxiliary systems like EGR, intercooler, hoses, etc. All recent CRDs have CCV blowby recycling - which means oil mist being routed back into the intake side of the engine (supposedly to be reburnt to meet US emission requirements), this oil can degrade turbo hoses (will in the case of Jeep) and clog up the intercooler and intake body (especially when mixed with soot recycling from the EGR). Fitting a Provent from new pretty much stops the black goop build up that clogs most CRDs over time. You can always stick one on an old engine but by then the stuff is already in there. There are ways to clean Intercoolers and hoses can be replaced with Samco silicon ones, but the intake body can't easily be cleaned without removing it (ie the head).

There is no better way of creating a million Kilometre CRD than buying it new, taking the necessary steps to remove or correct the system design flaws that they tacked on to meet the emission reqs, and looking after it obsessively. And I might add stay away from engines that cannot be fixed easily (like the Merc ones).