<html><body><div style="font-family: Arial; font-size: 12pt; color: #000000"><div aria-label="Compose body">Oh boy! A 'hot' (pun intended) topic right up there with oil and tires ;)<br></div><div aria-label="Compose body"><br></div><div aria-label="Compose body">'Coolant'--to my pedantic eye--is a mixture of water and antifreeze. The antifreeze is mostly ethylene glycol--some use propylene glycol, which is non-toxic but slightly less efficient--with some pump lubricant* and corrosion inhibitor. The corrosion inhibitor is a mild acid that gets 'used up' over time:<br></div><div aria-label="Compose body"><br></div><div aria-label="Compose body"><a href="http://www.google.com/patents/US6096236">http://www.google.com/patents/US6096236</a></div><div aria-label="Compose body"><br></div><div aria-label="Compose body">Usually, coolant life is expressed in miles; modern formulations can go over 100K miles before recommended change-out, but since our Healeys aren't going to be driven that much time becomes the issue (iron engines will rust just sitting). I would say change it every 5 years or so (which might only be a few thousand miles of driving for some owners).<br></div><div aria-label="Compose body"><br></div><div aria-label="Compose body">I believe the 'waterless' coolants are mostly propylene glycol and are quite a bit more expensive than ethylene glycol formulations. You'd still need to change it out when the corrosion inhibitors get used up; IMO it's a gimmick.<br></div><div aria-label="Compose body"><br></div><div aria-label="Compose body">Bob<br></div><div aria-label="Compose body"><br></div><div aria-label="Compose body">* it just occurred to me that the only thing that needs lubricating in a water pump is the bearings, but the last thing you want in the bearings is water. Am I missing something?<br></div><div aria-label="Compose body"><br></div><div><br></div><hr id="zwchr"><div style="color:#000;font-weight:normal;font-style:normal;text-decoration:none;font-family:Helvetica,Arial,sans-serif;font-size:12pt;" data-mce-style="color: #000; font-weight: normal; font-style: normal; text-decoration: none; font-family: Helvetica,Arial,sans-serif; font-size: 12pt;"><b>From: </b>"Daniel White" <healeydan@wowway.com><br><b>To: </b>"healeys" <Healeys@autox.team.net><br><b>Sent: </b>Thursday, November 5, 2015 5:53:14 AM<br><b>Subject: </b>[Healeys] Coolant change<br><div><br></div><div style="font-family: times new roman, new york, times, serif; font-size: 12pt; color: #000000" data-mce-style="font-family: times new roman, new york, times, serif; font-size: 12pt; color: #000000;"><div>I've searched the archives looking for any discussion regarding how often to change the coolant in the BN7. If the answer is there...I missed it. I'm running a 50/50 mix of antifreeze and tap water and it tests o.k. as far as freeze protection. This mix has been in the system for a number of years. Does coolant "go bad" with age? Any thoughts about the waterless coolant being sold on the market?<br></div><div>Thanks,<br></div><div>Dan White<br></div><div>1962 BN7 Mk II<br></div></div><br>_______________________________________________<br><br><div><br></div></div><div><br></div></div></body></html>