Antifreeze drain/flush replace.

[DougM]

Changing the antifreeze on my Yanmar 2GM20F is on the agenda because its due (probably overdue).This is not one of my favorite tasks Does anybody who does their own have any easy tried and true ways of doing this?
My boat is still on the hard, and I want to do the change before re-launching. I don't want to just drain it into the bilge then try to pump it out into a bucket. because I believe that is a bad idea for environmental reasons and because the bilge is presently clean and dry.
The next question is who will take and properly dispose of the old antifreeze?

 

[Ron20324]

I'm with you, Doug, with my B323. I have the antifreeze and distilled water to mix it 1/2&1/2. Even though I try (with both antifreeze and oil) I spill some. Dirt happens. Since I've owner a boat, I've never thrown away an old piece of clothing, because there are a lot of uses for them. IIRC there is an antifreeze tank at the marina located by the used oil tank.

 

[Gunni]

I wouldn't do it out of the water unless you can devise a method to run the engine. You need to circulate the flush, and then circulate the new AF, bringing up your level to full.

Pull out your manual and ID the coolant drain petcock locations. One will be on the low end of your heat exchanger, another likely below your freshwater water pump and a third on the other side of the engine. Fit a drain tube of proper diameter and direct the flow into a basin or bucket.

Fill and flush with fresh water, blow out the HW heater loop.

If you marina doesn't have a used AF drum, your municipality does.

If your boat has a engine loop to a hot water heater consider now as a good time to switch to one of the new industrial propylene glycol diesel antifreezes, non toxic for your potable water system exposure. Fleet guard and Starbright make highly rated products.

 

[NYSail]

Getting ready to do the same with my new boat..... When I replace mine, I always remove and replace the thermostat during the flush to quicken the process. A good time while you're in there.... my opinion. Also I am replacing all the hoses as well. Why not.....

 

[CaptainSV-SecondStar]

I echo the previous comments, particularly with the need to run the engine to circulate the coolant. That's particularly important when changing types of coolant too.

As for collection, the method I've found that works is doubled up tall kitchen garbage bags strategically placed under the petcocks. Additionally, I attached a clear plastic tube to each petcocks Dorian to further guide the fluid into the bags. If you are diligent this catches all the coolant and clean water flush, then I tie up the bags and put them relatively quickly into a Home Depot bucket. The bags will eventually leak but allow me to get them into something I can cover/put a top on and transport to our local municipal reclamation site.

 

[Ron20324]

Thinking of Captains post, I wonder if anyone has changed out the petcock to put in a shutoff valve and hose barb? IIRC they are maybe 1/4 threads?

 

[Gunni]

My petcocks all have a shutoff valve and a nipple to hold a drain hose.

 

[CaptainSV-SecondStar]

Gunni - same here. Even with nipples or hose barbs the challenge is where the line can lead from there. For Second Star, even with decent engine access and some bilge space below (and to port of the engine below the 2nd petcock) I can't get a bucket or other inflexible receptacle into the space, not to hold the volume of liquid coming out of each. And this task from my experience works best using gravity not working against it. Hence the plastic bags (which from an environmental perspective I do not like but they work) in the spaces below the petcocks to catch the liquid draining through the tubes.

If others have other or better practices, love to hear and learn!

 

[Gunni]

SecondStar; All you need to do is configure a siphon. Use a longer tube. Place your buck in a convenient location where the drain tube end will be lower than the petcock nipple. Make sure your coolant cap is off. When you open the petcock you will flood the tube and start a siphon. I cut my drain tubes so that I can drain all three petcocks to the same bucket at the same time.

 

[Scott B]

If your boat has a engine loop to a hot water heater consider now as a good time to switch to one of the new industrial propylene glycol diesel antifreezes, non toxic for your potable water system exposure. Fleet guard and Starbright make highly rated products.

Something I would not have considered, but I would guess leaks within the hot water tank would allow anti-freeze in the potable water.

 

[CaptainSV-SecondStar]

Gunni, thanks. I thought of that but doesn't the final level of the fluid need to be below the level of the nipples? If so, I haven't thought of / figured out a place for the bucket to meet that requirement.

 

[BigEasy]

I have to drain & flush mine also this weekend. Actually I am dreading it because I know its going to take half a day and probably going to be a mess. Gunni, do you suggest removing the thermostat to get a quicker flush. I am converting from the standard solution to the extended life solution. My understanding is that the system needs to be flushed with fresh water about 3 times to ensure all of the old stuff is cleaned out before replacement with Havoline extended life / non silicate concentrate mixed with distilled water. Depending on the condition of the old coolant, I might also do a Prestone cleaner flush first followed by fresh water flushes.

 

[thinwater]

Changing the antifreeze on my Yanmar 2GM20F is on the agenda because its due (probably overdue).This is not one of my favorite tasks Does anybody who does their own have any easy tried and true ways of doing this?
My boat is still on the hard, and I want to do the change before re-launching. I don't want to just drain it into the bilge then try to pump it out into a bucket. because I believe that is a bad idea for environmental reasons and because the bilge is presently clean and dry.
The next question is who will take and properly dispose of the old antifreeze?

Given that this is a fresh water boat (not chloride in the AF risk) and that engine hours are probably very low, 8 years is probably safe, just like a truck that is run little.

Salt water boats change more often due to risk of chloride contamination through the HE.

 

[dlochner]

To take some of the guess work out, use a refractometer to measure the specific gravity of the antifreeze. This model also works on battery fluids. http://amzn.to/2oyoXXr (Amazon Link)

 

[Gunni]

Gunni, do you suggest removing the thermostat to get a quicker flush. I am converting from the standard solution to the extended life solution.

I find that the coolant will drain just fine with the thermostat in place because there is drain both above (HE) and below (water pump) and the thermostat is not air tight. Earlier I was advised by Mack Boring to use an extended life coolant, but I believe the extensive research of Thinwater and his colleagues demonstrates that it more important change coolant often AND use a cavitation-protective coolant like the OAT types. Thinwater recommended my Fleetguard PG coolant. One benefit is that it is much more effective at heat exchange - which would potentially benefit a Gulf boater.

 

[Gunni]

doesn't the final level of the fluid need to be below the level of the nipples?

Given the engine install of a Beneteau, then engine bay configuration, and the amount of coolant being drained you should easily be able to find a location adjacent to the engine where a 5 gallon bucket can be placed and the siphon drain tubes routed.