Antifreeze Question

isaacs

Petty Officer 2nd Class
Joined
Oct 15, 2013
Messages
153
My boat runs flawlessly and has never had any rust coming out of the manifolds or engine block when I drain it. So why am I complaining? The price of pure propylene glycol antifreeze, which I have always used, is up to $8/gallon at Home Depot. I'm tempted to either use the cheap stuff (half the price) which contains ethanol, or simply drain it and leave it. Even though It has always been used in fresh water I'm concerned about rust/corrosion. Any thoughts on which of the three options I should take?
 

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
42,059
Any thoughts on which of the three options I should take?

Another oil thread type
My 1994 Rinker 454 and 1995 Formula 502 raw water cooled and "never" had any AF added. Both boats are still running (get messages now and then from owners) and no issues

Oh Edit: other views are coming, hold tight
 

nola mike

Vice Admiral
Joined
Apr 22, 2009
Messages
5,363
Another oil thread type
My 1994 Rinker 454 and 1995 Formula 502 raw water cooled and "never" had any AF added. Both boats are still running (get messages now and then from owners) and no issues

Oh Edit: other views are coming, hold tight
nope, you're right. quick mods, close the thread!
 

Scott06

Admiral
Joined
Apr 20, 2014
Messages
6,440
My boat runs flawlessly and has never had any rust coming out of the manifolds or engine block when I drain it. So why am I complaining? The price of pure propylene glycol antifreeze, which I have always used, is up to $8/gallon at Home Depot. I'm tempted to either use the cheap stuff (half the price) which contains ethanol, or simply drain it and leave it. Even though It has always been used in fresh water I'm concerned about rust/corrosion. Any thoughts on which of the three options I should take?
The cheaper AF i think does not have the corrosion inhibitors that the PG does have.
like AD i also just drain, i do take off the supply hose from the outdrive and use a short piece of old radiator hose to dump a little af down each water jacket. I use about a gallon and figure any residual water trapped in sand or grit gets diluted w af. Also put it down the hose to backwash through ps cooler and out drive pickup holes.

i also boat in fresh water and have never seen any scale corrosion etc an any of my boats jackets, and have maintained boats of Mine or family members that were 34 , 25, and current boat is 19 years old.

so you are fine just draining it and probing the holes in my experience. Others also have their way that im sure works for them
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,957
or simply drain it and leave it.
Ayuh,........ I've run 99% in freshwater, 'n have been just draining everything, for decades, without issues,.....

Air just don't freeze,......
 

ROY WILLIAMS

Chief Petty Officer
Joined
Aug 8, 2022
Messages
400
My MCM 470 engine is the heat exchanger . the auto antifreeze 60% and the distilled water 40% ... My auto engines are over 20yrs and no corrosion ..
I did the 5 yrs ago and changed the antifreeze ...
1984 Camaro ,1996 Impala ,and the 2000 Silverado ....my Boat engine is 1978 ..
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,850
So you are filling the block and manifolds with A-F for winter storage? I would use the cheapest automotive antifreeze, full strength, and drain and recover it in the spring. In freshwater, the RV stuff would probably work just fine, as well, do to very low corrosion potential.

My 4.3LX would use about 4 Gal to chase any residual water (after draining), and to fill it. I boated in salt water, so there was always corrosion in the block and manifolds. You need to shove a wire into each drain to clear it out.

On a related note: Don't forget to grease the steering rod in the bilge. If they corrode, they are a PIA to clean and re-lube.
 
Top