Real-world cooling problems can get pretty esoteric - Sometimes seen in large wet-sleeve diesels is cylinder overheating caused by cavitation on sleeve exteriors, restricting heat transfer. Interfering with existing mechanical resonances sometimes alleviates the problem - Usually accompanied by the Mechanic's Chant... --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .