Antifreeze circulation through engine

[JR Bates]

Probably a stupid question, why could you not trim the outdrive down into a drum of marine antifreeze start the engine and circulate the antifreeze throughout the engine? I have a 2000 bayliner 2050 with a alpha one out drive & a 5.0 305 mercruiser engine. It looks difficult to drain all the different areas. The YouTube videos I have watched show 305’s with 5 blue drain plugs to drain. Maybe mine is older but I see no such drain plugs. Maybe the amount of antifreeze needed would be cost prohibitive or something.

 

[Lou C]

NO
1) your impeller will burn up trying to do that
2) unless you drain the engine first, or remove the thermostat, the raw water will not exit the engine on a cool fall day and you will wind up with manifolds full of AF and an engine still with raw water in it, and likely a cracked block in spring.
people don't understand how raw water cooling works, the system has excess capacity, so the thermostat allows hot water to leave the engine, only as much as is needed to maintain a temp that is about the rated temp of the stat. On a cool fall day, idling with no load, it may not open at all, or may only open slightly. So the raw water is still (mostly) in the block. Now when you are running up on plane, engine at normal temp, yes the stat is all the way open because its under load.
There are no short cuts, learn the right way, or pay the price!

SOOOO....
drain it the right way, you can back fill with AF if you want but you must DRAIN or else you will be buying a new engine come spring.

 

[Scott Danforth]

unless your block was modified by welding the lower drain ports closed, you have the drain ports

use them

if you try a block-buster 2000 kit or a scam-co kit, count on a broken block in the spring as Lou mentions

no way around draining unless you park your boat in a 10,000 gallon swimming pool of antifreeze, tie it off and put the boat in gear at full throttle and proceed pushing the bow up against the edge for about 15 minutes, you can not guarantee that the water in the block has been displaced

 

[Scott06]

Probably a stupid question, why could you not trim the outdrive down into a drum of marine antifreeze start the engine and circulate the antifreeze throughout the engine? I have a 2000 bayliner 2050 with a alpha one out drive & a 5.0 305 mercruiser engine. It looks difficult to drain all the different areas. The YouTube videos I have watched show 305’s with 5 blue drain plugs to drain. Maybe mine is older but I see no such drain plugs. Maybe the amount of antifreeze needed would be cost prohibitive or something.

Your plugs may be different if its older. Older ones used hex pipe plugs- there will be one on each side halfway down the block just above the oil pan rail. Not all exhaust manifold cooling fittings have plugs, you just remove the hoses to drain. The big U hose at the front of the block now has a drain plug, but older ones you just pull off the bottom of the hose off the water pup to drain.

I think on larger boats with insane engine compartments big marinas will use a big tank to circulate prop glycol through, but they have hundreds of gallons of it and run the engine for like 15-20 min, checking and topping af %.

Not sure how bad your boat is to acess but I can drain mine in 10 min even fighting a big beer belly thats in the way...

 

[Scott Danforth]

even fighting a big beer belly thats in the way...

Must go with the name......,.LOL

 

[nola mike]

Are the mani drains ¼ npt? Can't remember. Might as well go ahead and drain mine way early this year, and would like to put some type of tool less wing nut fitting on like on the block drains. Usually I winterize multiple times a year...

 

[Lou C]

OMC/Volvo engines use a brass plug with wing nuts on them that you can just put a small adjustable wrench on. Easy and they never break like the silly plastic stuff Merc uses. There’s a fitting threaded into the block and the plug goes into that fitting

 

[nola mike]

OMC/Volvo engines use a brass plug with wing nuts on them that you can just put a small adjustable wrench on. Easy and they never break like the silly plastic stuff Merc uses. There’s a fitting threaded into the block and the plug goes into that fitting

Yeah that's what I have for my block drains

 

[poconojoe]

When I'm done with those engine block drain plugs, I put them and my garboard drain plug in a zip lock bag and tape the bag to the steering wheel. I use electrical tape and put the sticky side out so the steering wheel doesn't get all gummed up. You can use whatever you want, a twisty or ty-wrap...instead of tape.

This way the block plugs are left off, just in case theres any residual water and they wont get lost because they are right in my face on the steering wheel come Spring.

 

[QBhoy]

Your thermostat wouldn’t open by the time you’ve emptied the water out the source, for a start.
just drain it all out…fill it with AF through the hoses and leave it filled with it. All will be well.

 

[H20Rat]

When I'm done with those engine block drain plugs, I put them and my garboard drain plug in a zip lock bag and tape the bag to the steering wheel. I use electrical tape and put the sticky side out so the steering wheel doesn't get all gummed up. You can use whatever you want, a twisty or ty-wrap...instead of tape.

This way the block plugs are left off, just in case theres any residual water and they wont get lost because they are right in my face on the steering wheel come Spring.

I like that idea, hard to forget them in the spring!

Replacements are really cheap and having one snap isn't fun, so I usually replacement mine every 3 years or so. I keep a full spare set in the tool box on the boat.

 

[poconojoe]

I like that idea, hard to forget them in the spring!

Replacements are really cheap and having one snap isn't fun, so I usually replacement mine every 3 years or so. I keep a full spare set in the tool box on the boat.

Good points.
I remember replacing the o-rings on one set. Later I bought a new set and wondered why I bothered replacing those o-rings!

I keep my old ones in the boat tool box.

 

[TyeeMan]

You can buy stainless steel wing nut type block drains. I did a couple years ago, they're awesome!

 

[Kubaat3lover]

How about leaving the plugs off? I did it once and no problem but read somewhere its not recommended also in Merc Manual they say do not leave it open.. (?)
I drain the block, then fill with antifreeze to flush and drain AF as well to be 100% sure there isnt any fluid left,

 

[Lou C]

Merc says that they want you to leave it in; that’s the only way it can fulfill its intended purpose (corrosion protection). They say you drain to prevent freeze damage and add AF (& leave it IN) to reduce corrosion.
Putting in AF and draining it is just a waste of money!
Merc says to replace the plugs because air gets to the threads and corrodes the cast iron. I put a bit of OMC gasket sealer on the metal drain plug threads and never had a problem.

 

[Kubaat3lover]

Ok but if You add AF via hoses there is a possibility the thermostat still can be closed right?
I still sleep better if my block is empty... there can be any water residue with AF mixed

 

[Lou C]

It does not matter, at all if it’s closed. To fill the engine after manual drain you simply disconnect the top end of the big hose at the thermostat housing and put a funnel in it. Then fill the engine via that hose till the AF spurts out the neck of the stat housing. Engine is full; reconnect hose. Been doing it this way 19 years and our winters get down to zero. I use either -100 or I mix up a batch of Sierra no tox AF.

 

[tonyjh63]

All I've ever done to mine (Merc 4.3) is remove the blue plastic drain plugs (5, I believe), and that's it. No warm-up, nothing. (No need to warm it up if I'm not putting AF in, correct?). Never gets really cold for days on end here in north Georgia, so I've been safe.
What else should I be doing?

 

[crazy charlie]

I guess I am in the minority however I have used Camco kit for the past 30 years and never an issue.Now ...I have my own way of doing it to be absolutely certain the stat is open but hear me out.I have twin 5.0 XL with alphas.rwc.My antifreeze gets stored in my boiler room 48 hours before winterizing.(my boiler room is very warm) Antifreeze is now warm.When I am combining the AF with water for the 50/50 mix I add warm to hot tap water.The 5 gal Camco tank is now toasty warm.This will assure that the Tstat stays open when switching over from cold hose water to warm AF tank.I run each motor on muffs/hose water until operating temp is reached,then I let it continue to run for another 10 minutes to assure the entire motor is warmed up before switching over to the AF tank.The engine temp will usually climb when the Af is introduced into the drive.Wifey watches the AF tank and yells to me when it gets to 1 gallon to go as I stand ready armed with a can of fogging oil in one hand and MMO in the other hand,Thats when I begin fogging through the carb and stall it out with a dose of MMO while fogging.Im am confident now but when I first started winterizing this way I would open petcocks and manifold plugs for a second or two after winterizing just to make sure AF came out.I have done this approx 60 times with zero issues.You can also just pull the stat when winterizing and bypass the whole warm AF deal .I really like my way.Charlie

 

[H20Rat]

I guess I am in the minority however I have used Camco kit for the past 30 years and never an issue.

How cold does it get? It obviously works for you, but there is a couple gallons of water that you need to displace first, and even then you are still mixing/diluting your antifreeze down. -40 isn't unusual for my winters, so mixing with any remaining water will be a problem.