Changing Coolant

[Dockhead]

It's that time of year again . . .

Time to change the antifreeze/coolant in generator and main engine.

You do do this, don't you? The anticorrosion package wears out, and you really need to change it as called for in the manual. Especially if you an engine with aluminum parts in contact with the coolant, like the larger Yanmars.

Only problem is the mess it makes. I have never been able to figure out a way to do this other than just drain it into the engine room bilge. Which then requires laboriously pumping it out with an oil change pump and humping it out for disposal. And then cleaning the bilge afterwards.

Is there another way to do it?

[Kenomac]

Glad you brought this up. We have the same engine, how do I drain the old coolant? Where is the drain plug?

[Dockhead]

Originally Posted by Kenomac

Glad you brought this up. We have the same engine, how do I drain the old coolant? Where is the drain plug?

I have always done it by pulling hoses off. But this makes a big mess and I'm sick of it, hence this thread.


This engine can particularly be damaged by failing to change the coolant, so be sure to do it. It's got lots of alu in it.

[Snowpetrel]

My nanni has a nice little tap on one side, drains 90% of the coolant, but the HX/manifold can be a fiddle to drain fully, still I usually end up with some mess to clean up.

[thinwater]

It isn't that the additives wear out that quickly. They last just as long as they do in your car. It is that there is a greater risk of chloride (sea water) leakage into the coolant. The condemning limit on chloride is typically about 1-2 part per thousand seawater in the coolant.

(water requirements from ASTM D3306)
Contaminatant in Water Maximum PPM
Chloride 25
Sulfate 50
Hardness 20

Sail Delmarva: A Marine Winterizing, Antifreeze, and Engine Coolant Primer

Chloride is a real bad actor in engines that are basically designed for cars and trucks. You will find that the recommended change intervals for the same engine in generator service is more in line with vehicle service.

[paulajayne]

Mityvac Fluid Evacuator — 2.3 Gal. Reservoir, Model# MV7201 | Oil Extractors| Northern Tool + Equipment

Shop around as they can be much cheaper.

[Dockhead]

Originally Posted by paulajayne

Mityvac Fluid Evacuator — 2.3 Gal. Reservoir, Model# MV7201 | Oil Extractors| Northern Tool + Equipment

Shop around as they can be much cheaper.

I have something comparable to this, but that doesn't answer my question -- where to stick the hose? With oil it's obvious, but with coolant, not.

[Dockhead]

Originally Posted by thinwater

It isn't that the additives wear out that quickly. They last just as long as they do in your car. It is that there is a greater risk of chloride (sea water) leakage into the coolant. The condemning limit on chloride is typically about 1-2 part per thousand seawater in the coolant.

(water requirements from ASTM D3306)
Contaminatant in Water Maximum PPM
Chloride 25
Sulfate 50
Hardness 20

Sail Delmarva: A Marine Winterizing, Antifreeze, and Engine Coolant Primer

Chloride is a real bad actor in engines that are basically designed for cars and trucks. You will find that the recommended change intervals for the same engine in generator service is more in line with vehicle service.

Thank you for this extremely interesting information, which has advanced my knowledge about antifreeze.


One eye-opener for me was that ethylene glycol is not toxic to marine life and biodegrades easily. I had no idea -- I thought it would be harmful to marine life as it is harmful to us. So this suggests that I could just pump it overboard rather than going through the hassle of sucking it up and humping it away.

[Exile]

Thinwater's post suggests that changing coolant more often may be advisable for any of our marine engines regardless of aluminum content. Never knew so thanks.

Along the lines of DH's comment about coolant being biodegradable/not harmful to marine life, I have also heard it's OK for home septic systems and thus to pour down the drain. There are nevertheless strict pump-out prohibitions where my boat is so probably wouldn't go that route.

Like DH, every time I've done this it's been a big mess. Next time I plan to use my vacuum pump to get as much as I can out of the overflow & manifold, drain from the bolt just underneath the thermostat, and then use a deep pan underneath the lowest hose. Famous last words . . . probably still be a big mess.

There are some friendly engine guys around the yard I am at right now. I'll ask around and report back if anything more enlightening is uncovered.

[Frankly]

Just replaced the coolant on Cbreeze earlier this week (3GM30) and used a 16 oz plastic soft drink bottle. Opened the drain valve with the plastic hose discharging into bottle. When the bottle is near full turn off the valve, and dump the bottle contents into a bucket. Repeat 8 or 10 times. Clearances in the motor box/ pan are such that the 16oz bottle is about all I can get below the engine. Took a little time and attention but was the least messy I have tried over the years.

I use a little 12Volt SS pump I purchased from Harbor Freight for the engine oil and pumping the transmission oil from a cut off plastic milk jug that I drain the transmission into. Best I have come up with so far and I have tried several different pump/ arrangements for over 50 years of this messy operation.

[rwidman]

My engine has five different drain points. I tried capturing the used coolant but I missed a lot and had to clean the bilge anyway so now I just drain it into the bilge.


I pump it out and into a bucket with one of the long plastic manual bilge pumps available at any marine retailer. Then I pour it into a five gallon gas jug reserved for this purpose, take it home, and try to find a place that will accept it for recycling or as hazardous waste. That is the hardest part, nobody wants it.


It only takes a few minutes to pump it out and rinse the bilge. This leaves me with a clean bilge as a bonus.


I think it's a terrible idea to dump used engine coolant into the water we boat in. If nothing else, at least dump it where it will get treated.

[arsenelupiga]

hard to believe your setups are that difficult. Mine yanmar 3jh5e x 2 change of coolant is 10 min task. 2 vents where one gets out 70 % of coolant.

More difficulty with heating as one has to ensure no airlock.

However, simply replacing 70 % each year instead of each 100% every 2 years as per manual seem to be easy way.

[a64pilot]

I know when sufficiently diluted ethylene glycol is allowed to be disposed of in storm drains.
Myself I have installed a prestone flush kit in my water heater exchanger hose, I hook up the water hose to it and open my drains on the engine and run water through it until it comes out of the engine clear, let it drain, close the drains and refill with antifreeze looking for a 50% mix, its as simple as that.

I was going to install a coolant filer and run the type of coolant that you can run permanently, but found out about the likely hood of contamination with seawater and scrapped that idea.

"Ethylene glycol does not persist in large amounts in ambient air because breakdown is rapid (half-life in air is 8-84 hours). In environmental exposure situations, its low vapor pressure precludes substantial inhalation exposure at ambient temperatures, and its poor skin absorption prevents significant absorption after dermal contact. Ethylene glycol is miscible with water and will leach through soil to groundwater. It biodegrades rapidly in soil (half-life, 2-12 days). The half-life ranges from 2-12 days in surface water and 4- 24 days in ground water. Because it is not fat soluble and biodegrades rapidly, bioconcentration and bioaccumulation are insignificant (Agency for Toxic Substances and Disease Registry 1997)."