why use antifreeze?......

[CliffA]

i'm just trying to learn when i ask this question so please understand i am not taking a position for or against the use of antifreeze in our boat engines during winter storage.....i'm just interested in hearing the pros and cons....sure this has been debated many, many times but i have not found an answer to my basic question concerning this practice....

i understand the primary reason to fill the water passages with antifreeze is to offer the walls of the passages protection from corrosion....what i don't understand is why this is so important because the other 8-9 months out of the year when the boat is being used no one seems to be concerned about this corrosion protection....is the rate of the corrosion somehow accelerated during the winter storage months when no water is being circulated through the engine?..i would think just the opposite is true...since the walls of the water passages are not being exposed to circulating water during winter storage i would think the rate of corrosion would naturally slow on its own even if no antifreeze is used because the walls of the passages would be dry....does the slowing down of the rate of corrosion for 3-4 months out of a year really extend the life of the engine and exhaust components that much?....

personally i have always just drained the water from the engine and exhaust and do not add antifreeze...i currently subscribe to the theory that 'air doesn't freeze' so once the water is drained the engine is freeze protected....i also boat in fresh water so the rate of corrosion is significantly slower for my engine vs. engines used in salt water....

i am certainly open to consdering starting to use antifreeze for the corrosion protection if someone can convince me it is really needed...

thanks....

cliff

 

[northern]

It goes to minus 40 where we are. I have a jetboat with a 350 in it. The engine is cooled by anti freeze via a heat exchanger the exhaust system is raw water. I blow all the exhaust water out with a shop vac after I drain all I can. Since 2009 it has worked for me.

 

[Molson]

adding antifreeze is not required. If drained, air will not freeze. AF with corrosion inhibitors will just help keep rust to a minimum while the engine sits for the winter.

 

[Sprint7TW]

personally i have always just drained the water from the engine and exhaust and do not add antifreeze...i currently subscribe to the theory that 'air doesn't freeze' so once the water is drained the engine is freeze protected....i also boat in fresh water so the rate of corrosion is significantly slower for my engine vs. engines used in salt water....

#1

 

[moparlvr4406]

My thoughts right or wrong.
granted air won't freeze but it wont protect either
corrosion or rust is oxidation and in my thinking the antifreeze not only displaces the small amount of remaining water it would add a barrier to prevent the oxygen from directly contacting the metal adding to the oxidation effects

 

[rabyers1]

Protection against oxidation is the primary benefit of antifreeze over air. Since it is common to leave the drain plugs out if you go the air route, you then create significant air flow thru the water passages, which causes fresh oxygen to continually come into contact with the metal surfaces. This will result in significant oxidation (rust) in that 3 month time period.

 

[Wylie_Tunes]

The single biggest goal with winterizing is freeze protection, i'm sure most would agree. Preventing rust and corrosion with the use of a Marine/RV antifreeze is not a bad thing, especially if your boat is stored for a long period over the winter. For those like us, that have a long boating season and a short lay-up period, I do not think rust/corrosion protection is a must. In fact, im not sure I can recall a boat engine that has ever rusted from the inside out, thus requiring replacement. Although boat service and repair is not my primary thing, I do winterize for some of my long time customers. Most do not feel the need for antifreeze and do not ask for it. For those that do it needs to be done effectively.

I read and hear of so many boaters running 5-10 gallons of antifreeze through their engines on the muffs or fake-a-lake. Then there's some that fire up the engine and wait till they see pink running out the exhaust, then stop, thinking the block is full and protected. There are two holes in this theory. 1) Marine/RV antifreeze is best used @ 100%. its not like automotive coolant that is best effective when mixed with water. So, if there is any water in the block, it will dilute the antifreeze and raising its freeze point. 2) Even is the engine was warmed up with fresh water prior to swapping the hose over to the antifreeze bucket, the thermostat will close as soon as the cold antifreeze hits hit. At that point, the antifreeze will be diverted to the exhaust, which always has fresh water flow regardless of the thermostat, and then exist the exhaust. For those that run a little through til they see pink, have ended up with very little protection. Those running gallons and gallons through, will get some into the block, but it may be diluted and it took a lot to get what you got in there.

IMHO, the most effective way to fill the block with antifreeze for the winter, is to drain the block of all water, remove the thermostat housing and thermostat, and pour the antifreeze in until the block is full. For those will a semi-closed cooling system, you should be good to just run some through the heat exchanger, or just drain the the heat exchanger and leave it.

Also, I do not believe in leaving plugs out and hoses undone during winterizing. This requires more work in the spring. I always leave my boats turn-key ready for spring. Just my $.02

 

[CV-23]

My thoughts right or wrong.
granted air won't freeze but it wont protect either
corrosion or rust is oxidation and in my thinking the antifreeze not only displaces the small amount of remaining water it would add a barrier to prevent the oxygen from directly contacting the metal adding to the oxidation effects

200% correct!!!

 

[alwhite00]

I drain it, run pink through it and then drain everything again. pink is not so much for the engine but all of the other passages/hoses that I am not 100% sure are drained.

LK

 

[sea hare]

IMO, letting the block sit empty with no AF is no different then the 6 mos it sits with lake water in it. There are no corrosion inhibitors in my lake water the last time i checked.

 

[ZZ13]

IMO, letting the block sit empty with no AF is no different then the 6 mos it sits with lake water in it. There are no corrosion inhibitors in my lake water the last time i checked.

I guess this is close to a thread hijack, but fogging fits right in there with me as well as something I just don't understand. People go 3-6 months during the season and never start their boat. Suddenly its going to sit a few months in cold weather and you gotta fog???

 

[sea hare]

I guess this is close to a thread hijack, but fogging fits right in there with me as well as something I just don't understand. People go 3-6 months during the season and never start their boat. Suddenly its going to sit a few months in cold weather and you gotta fog???

True, but protecting the cylinders is a much higher priority to me then a little rust in the waterjackets. A can of fogging oil is only like $3 and usually lasts me 2 seasons... so, what the heck...lol

 

[KHE]

My Dad has a 1976 Slickcraft with the Mercruiser 888 powerplant. Every fall, he drains the water from the block and manifolds and reinstalls the plugs. There has never been an issue with rust in 36 years...

 

[280DA]

Usually 40 below every winter here. Just pulled out the blue plugs, let's drain all water in the bilge, that's it that's all. Make sure that any drain hole is clogged. No problem at all. My boat is raw cooled. Worked for last 11 winter seasons.

 

[Larry]

IMO, letting the block sit empty with no AF is no different then the 6 mos it sits with lake water in it. There are no corrosion inhibitors in my lake water the last time i checked.

If the iron of the water jackets stay filled with water they rust at a much slower rate then if they were dry and exposed to air. There are rust inhibitors in AF, why would you not want to give your engine just a little extra protection? Sometimes with the cold to warm temp changes durring the Winter couses your engine to sweat (inside and out), which will promote rust...

 

[Lazy Daze]

I have fired up many a boat that sat with either no water in it, or just water for extended periods of time. The color of the water that comes out the exhaust is NOTICEABLY rusty colored. I have NEVER seen rusty water coming out of an engine that had AF in it for extended lengths of time. Remember, sometimes "I've never had a problem" could be better stated as "I haven't had a problem... YET".

 

[sea hare]

If the iron of the water jackets stay filled with water they rust at a much slower rate then if they were dry and exposed to air. There are rust inhibitors in AF, why would you not want to give your engine just a little extra protection? Sometimes with the cold to warm temp changes durring the Winter couses your engine to sweat (inside and out), which will promote rust...

I understand what youre sayin, and dont disagree, but I feel that my engines will be far worn out from use before it rusts to death

 

[MonacoMike]

Corrosion build-up will slow the heat transfer making the engine run hotter...

MM

 

[Woody]

If the iron of the water jackets stay filled with water they rust at a much slower rate then if they were dry and exposed to air. There are rust inhibitors in AF, why would you not want to give your engine just a little extra protection? Sometimes with the cold to warm temp changes durring the Winter couses your engine to sweat (inside and out), which will promote rust...

Actually I think this is backwards. Because water is needed in order to rust, that exposed to just air will rust slower.

 

[MonacoMike]

If the iron of the water jackets stay filled with water they rust at a much slower rate then if they were dry and exposed to air. There are rust inhibitors in AF, why would you not want to give your engine just a little extra protection? Sometimes with the cold to warm temp changes durring the Winter couses your engine to sweat (inside and out), which will promote rust...

Actually I think this is backwards. Because water is needed in order to rust, that exposed to just air will rust slower.

Rust is oxidation most rapidly formed in an environment with the required oxygen accelerated by moisture (water) allowing the oxygen to to react with iron hydroxides froming the corrosion. This rust consumes the iron to create a new material that can grow larger than the original material.

A drained, moist, oxygen filled marine engine is the perfect environment for the accelerated creation of this rust. This corrosion is not near a conductive as the original iron for heat transfer which is what the cooling system is all about. we also have not discussed the cost of manifold and risers in this thread but antifreeze is chaep compared to the cost of these hard parts.

I think anyone not using antifreeze is taking a risk and would de-value their boat for me as a purchaser for two reasons. One if they are willing to take that risk what other risks did they take, like cheap oil etc? Two what interior corrosion will I have to pay for?

MM