I changed nmy first set of plugs in 1955 and have never seen a plug come apart. Neither have I ever broken a plug. I contacted Volvo today at the 800# and asked them if they would like to have the plug. The customer service tech said he would send the report to the product group and they would respond if they deemed it necessary. When the plug disassembled on Monday, I had a terrible feeling that a piece was going to end up in the combustion chamber and do something terrible to the low-mile engine. I was sooo relieved to find the intact porcelain core. It meant no worries about destroying a valve or damaging the cylinder. In checking the records, the plug was actually installed at around 23,500 miles in 1997 in Cincinnati, Ohio, by the former service manager of Beechmont Motors. All other service was performed by Ravenna Volvo in Seattle. I had never before attempted to do anything to the Volvo on my own, except wash it and drive it.