Draining / replacing the antifreeze

May 4, 2010
9
Cabo Rico 38 Rock Hall, MD
I have a Westerbeke W46 and the pencil zinc seems to have broken off in the heat exchanger. I was going to remove the heat exchanger so I could remove the end caps, clean the zinc bits out, and clean out the tubes while I'm in there. I can't figure out how to drain *all* the coolant from the block. There is nothing in the manuals. I'm assuming there is a plug bolt somewhere. It's been suggested to just drain at the hot water heater hoses, but that does not seem low enough to drain what's in the block. I don't know how long the coolant's been in there, so I figured I'd replace it while I clean out the heat exchanger. Maine, I saw your pics of the Westerbeke heat exchanger you rebuilt, so I figure you must have the skinny on what I at first thought would be an easy job. -Tom
 

weinie

.
Sep 6, 2010
1,297
Jeanneau 349 port washington, ny
When I chatted up my boatyards mechanic about changing these zincs, he said not to bother since they break off and end up getting stuck in the heat exchanger. After seeing Maine's rebuild pics, I think I am in agreement. I'm thinking that it would be easier to troubleshoot and replace a leaky heat exchanger that has corroded rather than than try to figure out why my engine isn't cooling properly if pieces of zinc clog it up. Since I probably wouldnt take apart the heat exchanger anyway, either way would require me to replace the whole unit.
 
Feb 26, 2004
22,903
Catalina 34 224 Maple Bay, BC, Canada
Salty - don't worry about getting it all out. Just crack a convenient hose and put a bucket under it. Using the petcocks on the engine is sometimes a bear to not get coolant all over your engine and the mounts and the rubber.

weinie - WADR, your mechanic is a jerk. You need to service your HX and replace the zincs regularly. In fact, many times the overheating many experience is NOT from particles of zincs in the HX, it is at the inlet port of the HX from the rw pump where the cold seawater first meets the hot water coolant. If you're in salt water, that port rapidly clogs. That's why I have been recommending for years that folks take the whole HX off the engine and give it a good checkout. It'll also tell you if you HX shell is being rubbed by the mounting bracket, which could cause catastrophic failure, pretty rapidly. You should examine your zincs at least every three months. If they're fine, put 'em back in, but if you don't remove 'em and don't regularly, you'll never know how soon they die, or how "hot" your boat and its environs really are, will ya? Oh, and while I'm at it, your zincs cost a few bucks piece, right? How much ya think a new HX costs? In case you haven't figured it out yet, I think the advice you've been given is, well, faulty and self serving of your "mechanic." ;)

http://c34.org/bbs/index.php/topic,5078.msg37297.html#msg37297
 
Dec 2, 1999
15,184
Hunter Vision-36 Rio Vista, CA.
If you are changing to a different type of anti-freeze (green to orange - extended life) you should be sure to flush the entire system and get all of the green stuff out.

We have seen some real messes where the old type was mixed with the new. If you are sticking with the older (green) you may just be satisfied with a drain and refill.
 
Feb 26, 2004
22,903
Catalina 34 224 Maple Bay, BC, Canada
Good point, Steve. In that case, I am almost certain that the petcock on the block will NOT get all the old coolant out, and that you're better off to find a lower spot, like one of your hoses, but not necessarily the one to your hot water heater if you wanna catch what's in there. If it was my boat, I'd drain what I could from below my freshwater coolant pump hose, then run some clean fresh water (distilled wouldn't hurt), run the engine for a while, and then drain again. My hot water heater is under our galley sink and way down low, and while I just might jury rig something to catch the coolant, I'm afraid more would leak into the bilge than I could catch! :)

Good luck.
 
May 4, 2010
9
Cabo Rico 38 Rock Hall, MD
Thanks Stu. So if I just drain the coolant from a water heater hose, how much of the coolant can I expect to drain? The reason I ask is that from what I've read, it's a good idea to flush out the coolant circuit every few years and as this boat is new to me, I have no idea when or even if ever it was flushed or changed last. The engine is 24 years old, but only has about 1000 hours on it, so I'd like to maintain it to the best of my abilities. Am I over-complicating this? Thanks.
-Tom Fuhs
s/v Eclipse
Cabo Rico 38 #115
 
Dec 2, 1999
15,184
Hunter Vision-36 Rio Vista, CA.
Salty:

I would think if you put a hose one one end of the line (disconnect the other end) and turn on the water until it is clear that should take care of the water heater circuit. This may work on the engine side of the loop too.
 
Oct 29, 2005
2,360
Hunter Marine 326 303 Singapore
If you are changing to a different type of anti-freeze (green to orange - extended life) you should be sure to flush the entire system and get all of the green stuff out.

We have seen some real messes where the old type was mixed with the new. If you are sticking with the older (green) you may just be satisfied with a drain and refill.
Steve, what about changing from Orange to Red color coolant? Need to thoroughly remove the Orange?
 

weinie

.
Sep 6, 2010
1,297
Jeanneau 349 port washington, ny
ok.. i changed the zinc yesterday. I figured any zincs pieces that were previously inside were probably gone by now anyway. :)
 
Mar 26, 2011
3,609
Corsair F-24 MK I Deale, MD
You're going to ned to do better than just give a color.

Steve, what about changing from Orange to Red color coolant? Need to thoroughly remove the Orange?
I formulate coolants for a major producer, and the color is not a dirrect indicator of chemistry. However, you can simplify your life by going with any of a number of "global" or "universal", typically yellow, products that have very broad compatibility. They should last many years, unless you thing some few drops of seawater may be leaking in (1 % of the system volume would be signifigant), in which case annual changes make more sense. Chloride contamination is a big deal for systems not desgined for it.

Probably orange to red is compatible chemisrty. Really, only the green to Dexcool (orange) has been associated with trouble.
 
Jan 26, 2008
50
Hunter 31- Deale
I changed from Green to Orange (DexCool) on a 2GM20F - Key was flushing out the old stuff. The hard part was getting the antifreeze from the lower part by the water heater - Used a drill pump to suck out the anti-freeze into bucket. Filled with fresh water rain the engine (with thermostat removed so I didn't have to wait for engine to warm out and thermostat open). Because I was going from green to orange I did this several times. Then I added DexCool (50/50 pre mix) rain engine open the cooling cap and kept adding 50/50 Dexcool until I sure it was full (air out of line).

The drill pump did the trick to suck out the anti-freeze in the hose going to the water heater (there are no drain points that low).

Coast Awhile
Hunter 310
 
Feb 6, 1998
11,693
Canadian Sailcraft 36T Casco Bay, ME
If changing antifreeze, the best thing to do, especially if your engine had or has "Death-Cool" in it, is to thoroughly flush it out, clean it, and start fresh.

To do this on a Westerbeke;

1- Remove t-stat and replace cover housing using a spare gasket

2- Remove HX (might as well clean and have pressure tested)

3- Purge old AF out of engine with pump into 5 gal bucket.

4- Use an acid resistant pump and circulate Rydlyme through engine block to clean cooling passages

4- Flush Rydlyme with water then fill bucket with distilled water and circulate through engine

5- Drain off what you can of the distilled, replace HX, t-stat and add antifreeze. The "Globals" are good. Death-Cool (AKA Dex-Cool) does NOT like all the dissimilar metals in marine engines and can create Dex-Sludge.

Death-Cool Sludge:



6- Purge air and test AF concentration with AF tester..

Circulating Rydlyme:


Connection points:



For air purging I replace the cheap "pet cock" on top of the t-stat housing with a 1/4 turn ball valve. I then add a barb and some clear hose to it. Run the hose well higher than the highest point in the cooling system. Fill the hose with AF using a transmission funnel, open valve and start engine. As the t-stat opens and closes AF will gravity feed into engine and no air will be left in the system. Air=bad. Once the system is no longer taking AF out of the clear tube close the valve and drain the hose back into the AF container..

Air Purging Valve:
 
Feb 8, 2009
118
Sabre 34 MK-1 Annapolis, MD
An ideal to live up to!

Somehow, my engine isn't quite clean enough to eat off of. And if I were to use a nice white carpet as a work surface for major engine repairs, it wouldn't be as clean as Main keeps his.

Seems I have to step up my game just a little....

Harry
 
Jul 1, 1998
3,062
Hunter Legend 35 Poulsbo/Semiahmoo WA
Water Heater coolant removal: < 5 seconds!

I changed from Green to Orange (DexCool) on a 2GM20F - .......... The hard part was getting the antifreeze from the lower part by the water heater - Used a drill pump to suck out the anti-freeze into bucket. .........

The drill pump did the trick to suck out the anti-freeze in the hose going to the water heater (there are no drain points that low).
There is one very easy way. Here is my (formerly) secret trick: Use your air horn.

Disconnect the two hoses at the engine, put one in a bucket and the other up TIGHT against the air horn and lightly push the button. Guaranteed that in less than about five seconds all the coolant will be out of the lines.

Keep it simple. Works every time!
 
Dec 30, 2009
680
jeanneau 38 gin fizz sloop Summer- Keyport Yacht Club, Raritan Bay, NJ, Winter Viking Marina Verplanck, NY
hi all, I have a winterizing ? a little off the original subject here,I usually remove my sea water pickup and place in a 5 gal bucket with a hose, and run the engine for 5 minutes then put the pick up into a fresh gallon bottle of anti freeze and run till solid green come out the exhaust, shut down. The fresh water side of the engine already has anti-freeze, is this method good for me Haverstraw NY area?? thanks Red