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The pistons are lighter and the rings closer to the poston crown and thus run hotter. That can coke the oil in the ring lands. The rings have lower pressure on the cylinder walls to reduce friction. That can increase blowby and oil contamination and may be part of some sludging cases. These 'features' can all combine in a negative way. The cylinder head bolts went though an era of not been torqued properly and cost savings which reduced their cost, strength and torque specs. The problem seems to have been solved. The old oil pumps were mush more robust. The current versions can wear and not work well if the engine has been neglected. So a engine that needs some TLC, chemical cleaning or rebuilding can be bogus and have inadequate oil pressure until the pump is also replaced.
The pistons themselves seem ok, crank, bearings, cams, lifters and valves seem to be without complaint. The few cases of cracked pistons seem to be the result of bad MAFs in combo with the higher output engines (Viggen and 9-5 Aero).
The folks who have done stage 3 mods and beyond are demonstrating that the basic engine is tough enough to withstand those mechanical and thermal loads.
So maybe the 9-5 will last, mechanicaly, a long time. But I have a fear that these vehicles, and all vehicles of this era may have lifetimes dictated by the costs of replacing electronics or even by replacment electronics not being available at all. Some specialized parts such as motorized throttle bodies or ABS systems might be critical as these suffer from the temperature extremes under the hood. One could go to relacement engine management systems, but I think that one would have to abandon motorized throttle bodies and then loose traction control, and levels of intigration with ABS and ESP.
, Sat, 15 Apr 2006 11:29:51
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