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--></style></head><body lang=EN-US link=blue vlink=purple style='word-wrap:break-word'><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>Perhaps the thinking is draining the water will keep the system from being over pressurized and prevent hoses from rupturing?<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>John <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>From:</span></b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'> engl@accesscomm.ca <engl@accesscomm.ca> <br><b>Sent:</b> Monday, November 3, 2025 8:01 PM<br><b>To:</b> healeys@autox.team.net<br><b>Cc:</b> 'Bob Spidell' <bspidell@comcast.net>; 'JSARCH' <jmsdarch@sbcglobal.net><br><b>Subject:</b> RE: [Healeys] Core plug query<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:9.0pt;font-family:"Century Gothic",sans-serif'>JSARCH is correct for many types of modern sprinkler heads, but there are still several types that use one form or another of fusible links. I apologize for being a pedant on this topic (sorry, it is what I do – both being a pedant and design of automatic fire protection systems).<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:9.0pt;font-family:"Century Gothic",sans-serif'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:9.0pt;font-family:"Century Gothic",sans-serif'>Mandatory Healey content : what is the advantage of draining the water from one’s cooling system if the engine is overheating?<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:9.0pt;font-family:"Century Gothic",sans-serif'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:9.0pt;font-family:"Century Gothic",sans-serif'>Thanks.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:9.0pt;font-family:"Century Gothic",sans-serif'><o:p> </o:p></span></p><div><p class=MsoNormal style='margin-bottom:12.0pt'><b><span style='font-size:10.0pt;font-family:"Century Gothic",sans-serif;color:navy;mso-ligatures:standardcontextual'>Bob England</span></b><span lang=EN-CA style='font-family:"Century Gothic",sans-serif;mso-ligatures:standardcontextual'><o:p></o:p></span></p></div><p class=MsoNormal><span lang=EN-CA style='font-size:9.0pt;font-family:"Century Gothic",sans-serif'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in 0in 0in;font-size:pt'><p class=MsoNormal><b><span lang=EN-GB style='font-family:"Calibri",sans-serif'>From:</span></b><span lang=EN-GB style='font-family:"Calibri",sans-serif'> Healeys <<a href="mailto:healeys-bounces@autox.team.net">healeys-bounces@autox.team.net</a>> <b>On Behalf Of </b>JSARCH via Healeys<br><b>Sent:</b> November 3, 2025 12:44 PM<br><b>To:</b> 'Bob Spidell' <<a href="mailto:bspidell@comcast.net">bspidell@comcast.net</a>>; <a href="mailto:healeys@autox.team.net">healeys@autox.team.net</a><br><b>Subject:</b> Re: [Healeys] Core plug query<o:p></o:p></span></p></div></div><p class=MsoNormal><span lang=EN-CA><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>More often than not, automatic fire sprinklers are activated by a glass bulb filed with a liquid that expands and breaks the bulb which then opens the fire sprinkler head. Bismuth is used in fusible links which that melt at certain temperatures to activate automatic fire doors.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>From:</span></b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'> Healeys <<a href="mailto:healeys-bounces@autox.team.net">healeys-bounces@autox.team.net</a>> <b>On Behalf Of </b>Bob Spidell via Healeys<br><b>Sent:</b> Friday, October 31, 2025 11:13 AM<br><b>To:</b> <a href="mailto:healeys@autox.team.net">healeys@autox.team.net</a><br><b>Subject:</b> Re: [Healeys] Core plug query<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal style='margin-bottom:12.0pt'>I did a little diggin ... <br><br>Apparently, they are designed to melt if the engine overheats, which would be grounds for voiding the warranty on a re-man. I wonder if the plug is made of bismuth, which is what sets off automatic fire sprinklers.<br><br><a href="https://www.toyotanation.com/threads/mysterious-plugs-in-engine-block.1659464/">https://www.toyotanation.com/threads/mysterious-plugs-in-engine-block.1659464/</a><o:p></o:p></p><div><p class=MsoNormal>On 10/31/2025 5:08 AM, Simon Lachlan via Healeys wrote:<o:p></o:p></p></div><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><p><span lang=EN-GB> I saw this on Facebook just now. Just curious….what’s that thing in the middle of the core plug? And, if it’s a good thing, why don’t all the plugs have one? </span><o:p></o:p></p><p><span lang=EN-GB>Thanks, Simon</span><o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p></blockquote></div></body></html>