Went to winterize the Yanmar 3GM30F on our Hunter 356 and got to the point of draining the green antifreeze out of the engine. Opened the cap on the heat exchanger and then opened the drain on the bottom rear of the heat exchanger - nothing came out even though I could see fluid in the unit. Went so far as to completely remove the drain valve body but nothing came out. Tried to see if there was something blocking the flow by inserting a toothpick as far as it would go but that did not do anything. Am I missing something? Has anyone run across a problem like this?
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Ignoring the issue of why drain the antifreeze as part of winterization, the drain you likely opened is on the raw water side of the heat exchanger. There are two on the heat exchanger, the other being the closed loop portion which contains the antifreeze. Sounds like you picked the wrong one.
If it is your intent to change the antifreeze, keep in mind you will need to also drain the lines running to the hot water heater, especially if you intend to replace the green stuff with the low silicate long-life type antifreeze.
If it is your intent to change the antifreeze, keep in mind you will need to also drain the lines running to the hot water heater, especially if you intend to replace the green stuff with the low silicate long-life type antifreeze.
Multiple drains?
While Don was writing the correct response I was over on Torresen to remind myself of the procedure:
http://forums.torresen.com/sailing/viewtopic.php?f=3&t=3329
This is something that I have never done so I am paying attention. I simply check the specific gravity and add if necessary. I suppose the anti-freeze should be changed on some schedule.
While Don was writing the correct response I was over on Torresen to remind myself of the procedure:
http://forums.torresen.com/sailing/viewtopic.php?f=3&t=3329
This is something that I have never done so I am paying attention. I simply check the specific gravity and add if necessary. I suppose the anti-freeze should be changed on some schedule.
The below advice, from Mack Boring, is for the Yanmar 3GM30F.
"Coolant Change – Yanmar 3GM30FC (Japan, circa 1999)Coolant Change – Yanmar
3GM30FC (Japan, circa 1999)
Background:
Yanmar accepts the following antifreeze applications in their products, present
and past models:
1. Ethylene glycol-Changed annually regardless of hours of operation.
2. Extended Life Antifreeze or Coolant (Meets or exceeds ASTM D3306 & D4985)
Changed every two years or 250 hours whichever comes first.
-Yanmar Ultralife YG30
-Dex-Cool Long Lfe Coolant
-Havoline Extended Life Antifreeze
Benefits of extended life coolants:
1. reduces hard scale build up
2. better heat transfer
3. no phosphate or silicate formation
4. long term corrosion protection for aluminum, bronze and cast iron
5. improved water pump life
Thomas J. Watts
Technical Support, Mack Boring & Parts Company
908-964-0700 ext. 286
tomw@mackboring.com
Equipment List:
0.5 gal Dexcool-type Extended Life Antifreeze (ex. Prestone 5yr/150000mi)
Or 1 gal of pre-mix version of above
Coolant system flush (must be safe for aluminum) (ex. Prestone Super
Flush)-Optional
Pliers
Funnel
Bucket or catch-basin
Water (Makeup water should be soft water or distilled water)
Instructions:
1/ On a cool engine, loosen the filler cap and drain old coolant into container.
On my engine, there are 3 drain points. Most volume came out of the block drain
fitting on the port side just aft of the oil filter. Approx. 16 oz came out of
the 2 drains on the heat exchanger, starboard side.
2/ After draining the engine, remove one of the hot water tank hoses from the
top front of the engine. Keep the 2 coolant drains on the engine open. Put on
the radiator cap and put your finger over the opening on the engine where the
hot water heater hose was connected. Clean off the hot water heater hose and
then blow on the hose and the hot water heater loop is emptied (about 1/2
gallon).
3/ Remove and clean the overflow tank. It pulls straight up off of its mounting
bracket.
4/ Close all drains and fill with water. Replace filler cap. Run engine until
thermostat opens and temperature stabilizes. Then shutdown and allow to cool.
5/ Drain (ie. Repeat step 1) Refill with coolant system flush chemical
(optional) plus water as required to fill. Run engine until thermostat opens.
Shutdown and allow to cool.
7/ Drain (ie. Repeat step 1) Refill with water to flush out the cleaning
chemical (ie. Repeat step 3). Do this 3 or 4 times until drained water is clean
and free from ethylene glycol (green) antifreeze.
Note: if you are staying with the EG antifreeze or did not use the flush
chemical, 1 or 2 water flushes should be sufficient.
8/ Drain for the last time. Refill with the 50/50 mix of Dexcool-type extended
life antifreeze. Fill overflow tank slightly above the "min" mark.
9/ Start engine, check for leaks and proper temperature. After shutdown, recheck
level in overflow tank."
Note: Some people believe that Dex-Cool should not be used in the Yanmar. I checked with Mack Boring and they stand by their recommendation. Other info on this subject is at:
http://www.imcool.com/articles/antifreeze-coolant/dexcool-macs2001.php
I am a bit confused. My Yanmar manual shows three drains for the green antifreeze and one of them is on the aft end of the heat exchanger; the other two are lower and on the block. There are no drains on the engine for the raw water shown in the manual. Am I missing something or is your engine different then mine?
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