Unfortunately there is no one single answer for each engine.
The only answer is this: However much PG (propylene glycol) it takes, so that what is coming out the exhaust exactly matches the strength of what came out of the bottle.
In our shop we use sight refractometers and occasionally hydronic heating system test strips. This is done so we know exactly what it takes on my own boat and on our customers boats. Every boat will be different depending upon hose lengths, flow characteristics, HX capacity, muffler capacity, engine driven refrigeration, and impeller condition.
Testing really only needs to occur once and then the exact amount recorded so it can be repeated the next year.
It is important to know that PG antifreeze should not be diluted. The rating on the bottle is the burst point, not the freeze point. Little things like draining the strainer and muffler, before sucking the PG in, can help you use less and keep the dilution to a minimum. Course at about $4.00 per gallon it is often easiest just to suck in more to be safe.
The safest bet, if you want to use minimal PG, is to use a -100 that can be diluted slightly before issues happen.
Basically none of the PG antifreeze products should be diluted. The -50, -60 & -100 are all general guides for undiluted burst points and they are not set in stone or standardized tested freeze or burst points.
-50 for example contains only about 30% by volume, propylene glycol. Reducing that concentration, through dilution (the water already in the raw water loop), to just 12.5% PG by volume, raises the BURST POINT to about 20 F which is a far cry from -50 @ 30% PG by volume. In this example you can see that just a little dilution raised the burst point by 70f!
If you want to save money on the number of gallons of AF you buy it is a good idea to drain the raw water side first. Alternatively just use more antifreeze so you know it is not diluted. Engines are expensive, PG is cheap.
The raw water side on our boat can hold over two gallons of raw water between the strainer, hoses, HX, water-lift muffler and our refrigeration heat exchanger. This can mean major dilution and in Maine that is not a good idea.. This is why I often drain it first before sucking in the -60f or -100f PG and then test it with a sight refractometer. Now days I know exactly how many gallons it takes because I have tested what came out the exhaust. It takes about 5 gallons of AF to keep within the safe burst point range for Maine.
If you read the label on -60 for example it says copper pipes may burst at -60F but that plastic is only protected to -26F, gotta love small print, and this is undiluted. HX tubes are very, very thin copper and are likely more fragile than PVC. However many boats have plastic sea strainers. Even -60 PG has the potential to pop your plastic HX at -26 when not diluted at all.
Generally speaking many of the -50F RV propylene glycol products do not have an anti-corrosion additive, but some do. Most notably the-50, -60 and -100 versions sold by West Marine do have the anti- corrosion package. Usually the -60 PG or -100 PG "RV" products do have anti-corrosion additives but the -50F often does not.
You can also buy hydronic boiler antifreeze, which is PG with anti-corrosives designed for protecting hydronic heating systems. It is very high quality stuff. They generally come in 5 Gal buckets made by folks like Hercules Chemical and sold as Cryo-Tek, and brands like No-Burst. These products however are very expensive, nearly $20.00 gal but are -100 rated and have very, very good anti-corrosion packages as many hydronic boilers are steel not just cast iron. Is this over kill, pretty much... The -60 or -100 PG from West Marine is a lot less money.
You can buy -100 from Hamilton or West, with corrosion additives for around $10.00 gallon.
West Marine Pure Oceans -50° (-46°C) Marine Antifreeze provides the ultimate in cold weather and corrosion protection for drinking water systems and all engines.
Note: The burst point of PVC pipes used in most drinking water systems is about -10°F (-23°C). When winterizing water systems in regions where temperatures can fall below -10°F (-23°C), we recommend using West Marine Pure Oceans -100°F (-73°C) Marine Antifreeze.
Before you suck any antifreeze in through the sea water strainer or engine consider the following:
#1 The -50f pink stuff (propylene glycol) is not intended to be diluted nor is the -60 or -100.
This quote is from Camco one of the largest producers of "RV" antifreeze.
Quote:
Originally Posted by Camco
Q. How much water should I add to your -50 RV Antifreeze to achieve a -25 burst protection?
A. Camco -50 RV Antifreeze should not be diluted. It is a pre-diluted solution that is designed to be used full strength. Additional water dramatically alters the expansion properties of the solution, making an adequate burst protection difficult to achieve.
#2 Your engine has a strainer (unless you by-pass it and drain it), hoses, HX and wet exhaust system that will already be full of water. One or two gallons of -50 pink stuff may not sufficiently prevent a freeze up if diluted with the 1+/- gallon of fresh water probably already in the system. Due to flow characteristics what you suck in does not always directly displace or expel what was already in there it "mixes"...
#3 If your vessel has engine driven refrigeration, like a Sea Frost unit, be sure to drain the refrigeration HX before sucking in the antifreeze as this alone contains at least a gallon of water.
Here in Maine we can see -20f to -30f. On occasion the occurs for up to a week at a time. It is critically important that if using the -50 antifreeze NOT be diluted and that it can withstand the temps in your region. You don't want to be buying a new HX, Water Lift or raw water pump..
I often drain all hoses, the wet exhaust water lift, sea strainer, engine HX and a Sea Frost HX before sucking any antifreeze through if I don't already know what the boat takes.. This allows me to buy less antifreeze as it is not getting diluted. Up here in Maine I often use the -100 stuff for a couple bucks more but only because of our potentially really low temps.
Nearly every spring I hear of someone at the local yards who froze their engine (RWC), HX , engine driven refrigeration HX or heat exchanger. I have also seen split sea strainers and seacocks that were not properly drained or winterized.
The power of ice is immense. This is a very heavy duty 1.5" bronze ball valve that was improperly winterized!!
If it can do this to a massive ball valve the ultra-thin copper tubes in your HX are no match...
Merely "seeing pink out the exhaust" does not tell you what the freeze point is or how diluted it has become. Engines & parts are expensive, antifreeze relatively cheap. When in doubt, or lacking proper test equipment, suck in an extra gallon or two or three.
I would suggest running more through, like four to five gallons, or draining the system before sucking it in will be less costly then a new HX or other frozen parts. Best bet is to check the freeze point of what is coming out the wet exhaust by catching it with a cup or bucket..
This is an impromptu video showing how I winterize my RW circuit.
The only answer is this: However much PG (propylene glycol) it takes, so that what is coming out the exhaust exactly matches the strength of what came out of the bottle.
In our shop we use sight refractometers and occasionally hydronic heating system test strips. This is done so we know exactly what it takes on my own boat and on our customers boats. Every boat will be different depending upon hose lengths, flow characteristics, HX capacity, muffler capacity, engine driven refrigeration, and impeller condition.
Testing really only needs to occur once and then the exact amount recorded so it can be repeated the next year.
It is important to know that PG antifreeze should not be diluted. The rating on the bottle is the burst point, not the freeze point. Little things like draining the strainer and muffler, before sucking the PG in, can help you use less and keep the dilution to a minimum. Course at about $4.00 per gallon it is often easiest just to suck in more to be safe.
The safest bet, if you want to use minimal PG, is to use a -100 that can be diluted slightly before issues happen.
Basically none of the PG antifreeze products should be diluted. The -50, -60 & -100 are all general guides for undiluted burst points and they are not set in stone or standardized tested freeze or burst points.
-50 for example contains only about 30% by volume, propylene glycol. Reducing that concentration, through dilution (the water already in the raw water loop), to just 12.5% PG by volume, raises the BURST POINT to about 20 F which is a far cry from -50 @ 30% PG by volume. In this example you can see that just a little dilution raised the burst point by 70f!
If you want to save money on the number of gallons of AF you buy it is a good idea to drain the raw water side first. Alternatively just use more antifreeze so you know it is not diluted. Engines are expensive, PG is cheap.
The raw water side on our boat can hold over two gallons of raw water between the strainer, hoses, HX, water-lift muffler and our refrigeration heat exchanger. This can mean major dilution and in Maine that is not a good idea.. This is why I often drain it first before sucking in the -60f or -100f PG and then test it with a sight refractometer. Now days I know exactly how many gallons it takes because I have tested what came out the exhaust. It takes about 5 gallons of AF to keep within the safe burst point range for Maine.
If you read the label on -60 for example it says copper pipes may burst at -60F but that plastic is only protected to -26F, gotta love small print, and this is undiluted. HX tubes are very, very thin copper and are likely more fragile than PVC. However many boats have plastic sea strainers. Even -60 PG has the potential to pop your plastic HX at -26 when not diluted at all.
Generally speaking many of the -50F RV propylene glycol products do not have an anti-corrosion additive, but some do. Most notably the-50, -60 and -100 versions sold by West Marine do have the anti- corrosion package. Usually the -60 PG or -100 PG "RV" products do have anti-corrosion additives but the -50F often does not.
You can also buy hydronic boiler antifreeze, which is PG with anti-corrosives designed for protecting hydronic heating systems. It is very high quality stuff. They generally come in 5 Gal buckets made by folks like Hercules Chemical and sold as Cryo-Tek, and brands like No-Burst. These products however are very expensive, nearly $20.00 gal but are -100 rated and have very, very good anti-corrosion packages as many hydronic boilers are steel not just cast iron. Is this over kill, pretty much... The -60 or -100 PG from West Marine is a lot less money.
You can buy -100 from Hamilton or West, with corrosion additives for around $10.00 gallon.
West Marine Pure Oceans -50° (-46°C) Marine Antifreeze provides the ultimate in cold weather and corrosion protection for drinking water systems and all engines.
Note: The burst point of PVC pipes used in most drinking water systems is about -10°F (-23°C). When winterizing water systems in regions where temperatures can fall below -10°F (-23°C), we recommend using West Marine Pure Oceans -100°F (-73°C) Marine Antifreeze.
Before you suck any antifreeze in through the sea water strainer or engine consider the following:
#1 The -50f pink stuff (propylene glycol) is not intended to be diluted nor is the -60 or -100.
This quote is from Camco one of the largest producers of "RV" antifreeze.
Quote:
Originally Posted by Camco
Q. How much water should I add to your -50 RV Antifreeze to achieve a -25 burst protection?
A. Camco -50 RV Antifreeze should not be diluted. It is a pre-diluted solution that is designed to be used full strength. Additional water dramatically alters the expansion properties of the solution, making an adequate burst protection difficult to achieve.
#2 Your engine has a strainer (unless you by-pass it and drain it), hoses, HX and wet exhaust system that will already be full of water. One or two gallons of -50 pink stuff may not sufficiently prevent a freeze up if diluted with the 1+/- gallon of fresh water probably already in the system. Due to flow characteristics what you suck in does not always directly displace or expel what was already in there it "mixes"...
#3 If your vessel has engine driven refrigeration, like a Sea Frost unit, be sure to drain the refrigeration HX before sucking in the antifreeze as this alone contains at least a gallon of water.
Here in Maine we can see -20f to -30f. On occasion the occurs for up to a week at a time. It is critically important that if using the -50 antifreeze NOT be diluted and that it can withstand the temps in your region. You don't want to be buying a new HX, Water Lift or raw water pump..
I often drain all hoses, the wet exhaust water lift, sea strainer, engine HX and a Sea Frost HX before sucking any antifreeze through if I don't already know what the boat takes.. This allows me to buy less antifreeze as it is not getting diluted. Up here in Maine I often use the -100 stuff for a couple bucks more but only because of our potentially really low temps.
Nearly every spring I hear of someone at the local yards who froze their engine (RWC), HX , engine driven refrigeration HX or heat exchanger. I have also seen split sea strainers and seacocks that were not properly drained or winterized.
The power of ice is immense. This is a very heavy duty 1.5" bronze ball valve that was improperly winterized!!
If it can do this to a massive ball valve the ultra-thin copper tubes in your HX are no match...
Merely "seeing pink out the exhaust" does not tell you what the freeze point is or how diluted it has become. Engines & parts are expensive, antifreeze relatively cheap. When in doubt, or lacking proper test equipment, suck in an extra gallon or two or three.
I would suggest running more through, like four to five gallons, or draining the system before sucking it in will be less costly then a new HX or other frozen parts. Best bet is to check the freeze point of what is coming out the wet exhaust by catching it with a cup or bucket..
This is an impromptu video showing how I winterize my RW circuit.
