I would say in your case robert not very often. Check the freezing point around here if its -20c or below good to go. Only other thing is depletion of corosion inhibitors i would also say your antifreeze is good on that. I use Prestone conc and dilute to 50/50 with distilled water. I had to replace my heat exchanger and my fresh water pump so i used a fresh mix to fill then. I have never changed coolant in any vehicles i owned. Very seldom did our lab see a need to change this in naval systems either. But it’s cheap so if you want some fun go for it
On Sun, Nov 18, 2018 at 11:16 AM Bruce Whitmore via CnC-List < cnc-list@cnc-list.com> wrote: > Hello Robert, > > Below is a post I put on the board about a month ago, which speaks to the > issue of the coolant itself. Your boat may be sufficiently old that all > its ever had is the standard green antifreeze, but nonetheless, you will > probably find this interesting. In the end, rather than having the concern > about Dextron antifreeze causing head gasket leaks hang over my head, I am > going to go with the newer "universal" long-life coolant, which I believe > is yellow (though the color means nothing anymore). As for the frequency > of coolant changes, Yanmar now recommends changing it EVERY YEAR even if it > is long-life coolant. The primary job of coolant (other than keeping it > from freezing) is stopping corrosion in the engine, and coolant breaks down > over time (especially the old style green coolant). This is why they > developed "long life" coolant which is supposedly good for 5 years. > > So, I'll probably plan on replacing the coolant every 2 years at the same > time I replace my impeller. > > Hope you find the reading below helpful. > > Hello all, > > As a result of a concern about tracking down a potential antifreeze leak > (which I haven't done yet), I wanted to confirm the coolant type. There is > no mention as to specific types either in my 3JH2E operating or service > manuals. Yes, I could go (way) out of my way to get Yanmar branded > coolant, but let's face it - it is not only way more expensive, its > available almost exclusively at Yanmar dealers, and the nearest one to me > is 15 miles away and isn't open on Saturdays or Sundays. And of course, > what happens if you need more when you're out cruising? > > In doing research, I found the following bulletin, published by Mack > Boring: > https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=4&ved=2ahUKEwizh_zu8Y3eAhWOy1MKHSFlD3cQFjADegQIBxAC&url=http%3A%2F%2Fldmarineservice.com%2Ffiles%2Fyanmar_bulletins.pdf&usg=AOvVaw3WK3R6vfJyTHOt5yGzFMDZ > > In the section about coolants, it recommends: > > Texaco Long Life Coolant, numbers 7991 and 7998. Unfortunately, one > really can't find either product on the web, so I can't seem to find if it > was orange (DEXCOOL) or red for diesels, or for that matter if it was > ethylene glycol or propylene glycol based. > > Havoline Extended Life Anti-Freeze/Coolant, number 7994. Per this link, > 7994 is DEX-COOL, but is ethylene glycol based. > https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=2ahUKEwij_o2I843eAhWK0FMKHXc5AfMQFjAAegQICxAC&url=http%3A%2F%2Fwww.rialtainfo.com%2Fvw%2Fvw_images%2Fradiator_%26_coolant.pdf&usg=AOvVaw3ZxHApMqFHHgB-qcUwOYWa > > Dex-Cool Long Life Coolant, which at least at the time of introduction was > propylene glycol based and is Organic Acid Technology (OAT) thus meaning > less toxic. Funny thing is, Dex-Cool was not even introduced until a year > after my boat was built (1995) and at the time, was only being used in GM > cars. > > Prestone Extended Life Coolant, product code AF888. Per the attached, > guess what, it's Dex-Cool. > https://www.autozone.com/antifreeze-radiator-additives-and-windshield-wash-fluid/antifreeze/prestone-antifreeze-engine-coolant/87934_0_0. > It is ethylene glycol based, but Prestone says it is OAT, which would seem > to conflict with what I can find about traditional Dex-Cool. > > Not entirely satisfied, I wanted to see what a Yanmar official publication > recommended. In a 2009 JH Series Operation Manual, it recommends Texaco > 7997 and 7998 (same as above). It also recommends Havoline 7994, as > above. It however says nothing about Dex-Cool or Prestone AF888. I get > similar results in a 3JH4E manual. > > Then, of course, I was faced with the fact that while I used Prestone > AF888 when I flushed and replaced my coolant, I was replacing what appeared > to be traditional green coolant (presumably old-style ethylene glycol). I > only now read a lot of horror stories of replacing green with orange > Dex-Cool, saying that one can never flush out the system sufficiently to > keep the orange coolant from gelling to the point the engine overheats. > > So, at this point I have no real idea what to thing other than the > Prestone AF888 I used should be OK as long as it doesn't a). Turn color > B) Gel up and c) My engine temperature stays OK. > > Sigh... > > Does anyone else here have anything more authoritative? (In the end I did > not receive any posts that were more authoritative) > > Bruce Whitmore > 1994 C&C 37/40+ "Astralis" > (847) 404-5092 (mobile) > bwhitm...@sbcglobal.net > > > > _______________________________________________ > > Thanks everyone for supporting this list with your contributions. Each > and every one is greatly appreciated. If you want to support the list - > use PayPal to send contribution -- https://www.paypal.me/stumurray > > > > _______________________________________________ > > Thanks everyone for supporting this list with your contributions. Each > and every one is greatly appreciated. If you want to support the list - > use PayPal to send contribution -- https://www.paypal.me/stumurray > > -- Sent from Gmail Mobile
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