Loads of the D22 navaras went bang, faulty con rod bolts, Mine have just give up but only after 220 thousand miles, yes that's not typo !!
All in all the D22 as a motor is brilliant, get the main bearing shells changed and adapt the oil pick up pipe in the sump and they're good for the 250
Costs about 160 quid for the parts but you have to take the sump off which means separating the engine and gearbox as two of the sump nuts are in the bell housing !
Can be bought cheap enough and a very good car once fixed