alternative coolant for yanmar

jimbeam

Well-known member
Joined
Aug 21, 2019
Messages
172
Fluid Motion Model
C-248 C
Hull Identification Number
FMLT2545G708
Vessel Name
waite & sea
Been trying to find havoline long life coolant (dexcool) which is recommended. Can't find it anywhere.
So, my question is, what are the alternative brands that will work just as well? I heard super tech extended life at Wal Mart would work just as well. Also prestone and autozone long life but need some expert opinions. Engine is a yanmar 4jh4hte
and I know yanmar now makes it's own coolant also. HeHe! thought changing the coolant would be a piece of cake but
murphys law is making life difficult.
Jim
 
jimbeam":1cnrzcni said:
Been trying to find havoline long life coolant (dexcool) which is recommended. Can't find it anywhere.
So, my question is, what are the alternative brands that will work just as well? I heard super tech extended life at Wal Mart would work just as well. Also prestone and autozone long life but need some expert opinions. Engine is a yanmar 4jh4hte
and I know yanmar now makes it's own coolant also. HeHe! thought changing the coolant would be a piece of cake but
murphys law is making life difficult.
Jim

The numbers in the yanmar manual are european numbers and will not match up with USA. You can use Dex Cool long life by prestone https://www.walmart.com/ip/Prestone...MI377Hz73F6AIVR4VaBR1pww6pEAQYBCABEgJVdvD_BwE Make sure that the product you buy is either straight or 50/50 mix and use accordingly. I change mine every year since you really can't get it all out with each change.
 
If the boat/engine are out of warranty just use any long life antifreeze. Like knotflying said rather than worry about completely draining it on the recommended interval you accomplish the same thing by replacing part of it every year with a lot less hassle. As long as the corrosion inhibitor is getting replenished it will do its job.
 
Dex Cool type formulations from the various manufacturers are designed specifically for engines with multi alloys in their system like our boat engines. They are called OAT coolants(Organic Acid Technology) and are said to significantly increase service periods and protection. Havoline, Rotella, Prestone, Texaco, are a few names .... Lots of opinions on the best ones, but my boat tech had a couple of overall suggestions.

#1 Stick to one brand once you do a total drain and fill...don't mix brands.
#2 Use distilled water to reduce strength to 50/50 if using a concentrate formula.
#3 DO NOT mix Dex Cool with Universal type antifreeze as gelling and sludge may occur along with an actual decrease in boiling point protection.

Tech discussions on this are lengthy...........but it seems these are his basic thoughts.....
 
In our Yanmar 4BY2, I use the genuine BMW blue coolant. Part number 82141467704. It’s concentrated so it needs to be mixed 50:50. Costs about $20 a gallon for the concentrate. This is the antifreeze BMW specs for the 320D N47 4-cylinder Diesel engine that Yanmar started with in their marine conversion. I’m sure there are other brands out there that work fine too.
When replacing coolant, make sure you get all the air out by “burping” the system. The amount you put in should equal the amount you removed. Just because the overflow bottle is full doesn’t mean you got all the air out.
 
Good point on burping....but as much as you try, you will somtimes still get the thermal alarm horn after running a few minutes......just remember to shut down and let it cool a bit before dumping cold coolant into a hot engine.......
 
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