1/- Is this model susceptible to timing chain failure like previous 380/500 V-8s ?
No, however the oil pressure check valve in the oil filter housing will leak and cause it to sound like a box of rocks on cold start. (which is hard on the chain and valve train, the oil tubes will blow off the cam towers and cause lifter noise as well.
2/- Is the engine wiring harness prone to slef-destruct like it did on the M104 engines (S320/E320s) ?
I've replaced a few, I figure 1 in 30 comapared to 104's.
3/- If the air conditioning evaporator was dealer replaced about a year ago, could it be likely to fail again in a near future (2 to 5 years) ?
LOL, 140's are hard on evaps.... period. I'd figure one every 3-5 years as a rule however, I think keeping it as dry as posible helps.
Project Smoker, '87 603 powered wagon
Hauler, 96 CTD can you say torque?
Toy 73 Cougar xr7 convertible
Acme Automotive Inc.