Winterizing the Mercruiser MX 6.2 MPI

stonyloam

Vice Admiral
Joined
Mar 13, 2009
Messages
5,827
Wow! And if that mechanic makes a mistake and the antifreeze is diluted, the burst protection of that antifreeze could go from -50 to +10 and you are done. I have nothing against antifreeze, but unles you drain the engine first you can never be 100% sure. So I agree with the Dodge man, anytime you use antifreeze to flush the water out of a block you are taking a big chance.
 
Last edited:

HT32BSX115

Supreme Mariner
Joined
Dec 8, 2005
Messages
10,083
My mechanic runs my boat up to temp an d then switches a valve on the hose he has a y type connection while the boat is running it circulates antifreeze through the entire system while the boat is running

If your engine is closed cooled, that's way works well.

If your engine has open or raw water cooling, I would find another mechanic.

If it's already been done for this season, Be sure the block is drained completely before your first freeze. Otherwise, you're "rolling the dice".............
 

littlerayray

Lieutenant
Joined
Feb 17, 2013
Messages
1,456
After the antifreeze has been circulated it is subsequently drained leaving antifreeze in the block as a precaution over raw water this method works here your method works where you are
There's more then one way to skin a cat and I will continue to use antifreeze as it has not hurt my block and in 3 years and we get temperatures in the minus 40s
 

littlerayray

Lieutenant
Joined
Feb 17, 2013
Messages
1,456
Here is an exert from the mercruiser manual recommending propylene glycol for cold storage
 

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
42,691
Come on now, lets not get in one of those contest here. We all know that Merc says fill with antifreeze, the only issue was not draining everything first. If after the system is completely drained putting antifreeze in is an option. Whether its needed after draining is where the opinion comes in
 

stonyloam

Vice Admiral
Joined
Mar 13, 2009
Messages
5,827
Yeah, that is a horse of a different color, if you're draining the system after the antifreeze that will be fine, since you are not relying on the antifreeze to displace the water in the block.
 

HT32BSX115

Supreme Mariner
Joined
Dec 8, 2005
Messages
10,083
Yeah, that is a horse of a different color, if you're draining the system after the antifreeze that will be fine, since you are not relying on the antifreeze to displace the water in the block.
The main thing we all want to do, is prevent one of the casual readers of these threads from thinking that it's "OK" to put their lower unit in a "tub" of 50:50, or "draw" up the mix using a flush adapter and think it's "all good"!!

You can probably do this, but you must FIRST drain the block and/or REMOVE the T-STAT so that ALL the MIX circulates in the block. (BUT understand that the residual water in the block WILL further dilute the "mix" in the tub if you let it drain back into the tub!!)

If you DO NOT remove the STAT, you CANNOT ensure that you'll get an adequate concentration of AF in the block.

This process breaks a good many blocks every year and some people come here asking why they have water in their oil after "winterizing" the way their favourite "pet" mechanic does (or after reading about it in a boating forum!!) !!

As long as you drain ALL the water from a block, you're "good".

If you choose to pour AF into the block afterwards (mixed at the correct concentration) Knock yourself out.......... You're still good!
 

littlerayray

Lieutenant
Joined
Feb 17, 2013
Messages
1,456
Sorry ht it just bugs me when people say don't use anti freeze and why wouldn't you if it gives you that added protection
 

HT32BSX115

Supreme Mariner
Joined
Dec 8, 2005
Messages
10,083
Sorry ht it just bugs me when people say don't use anti freeze and why wouldn't you if it gives you that added protection

It's probably because that benefit is not really measurable. That last engine I had *never* got AF in the 39 years My dad and I owned it and in fact didn't even get drained every year either (because it spent it's entire life in a garage during storage.

Many people don't do anything except drain the block for the life of the engine. (pretty much everybody I know) None of us have had ill effects as a result.

So even though a major engine/drive manufacturer suggests doing it (but doesn't make it mandatory) tells me that it might not really be required. (maybe their lawyers had them put that in there so they could always have an "out"..... My 1997 Owners manual only says that Winter Layup should be performed by an "Authorized Mercruiser Dealer"

Every year that I have been on this site, around APR-JUN, someone has come on complaining of a cracked block/water in the oil etc, and when asked, they claimed the engine was "winterized"...........

I've seen people right on this site try to say that it's OK to use AF drawn up into the engine via a "tub" or using "Muffs" etc. ALL without emphasising draining FIRST.

Truth be known in many of these cases, , there even WAS a mention of someone also suggesting draining some place in their discussion but as it turns out, some *thought* they'd be "OK" "at least doing the AF" because "they didn't have time to remove the drain plugs and poke around with a piece of wire" or couldn't find them all etc............, and thought they'd be fine, or actually got away with it the last couple of years etc etc etc

So, I guess to sum it all up. There's nothing "wrong" with pouring AF in your engine. (like I said above, You're Good!)

It's just NOT the most important aspect of "winterization". FULLY draining the the block IS.
 

lg260ss

Petty Officer 3rd Class
Joined
Jun 25, 2011
Messages
81
I am definitely in the "always drain first camp". And if I am going to back fill with antifreeze, I use the purple -100 AF from west marine. I have put the -50 in the freezer and guess what, It freezes. Not solid of coarse, but I'm not taking a chance that there is any water left in there.
 

bspeth

Senior Chief Petty Officer
Joined
Aug 30, 2013
Messages
758
Sorry ht it just bugs me when people say don't use anti freeze and why wouldn't you if it gives you that added protection
They say that because it does not give you extra protection,just makes you sleep better.Fine.Its not wrong( with the correct mix) but you don't need it.
 

stonyloam

Vice Admiral
Joined
Mar 13, 2009
Messages
5,827
The reason that a block cracks is that when WATER freezes it expands about 9%, and if the block is full it has no where to go and creates enough pressure to burst the block. While it is true that -50 RV antifreeze will solidify at about +10 F it DOES NOT EXPAND enough to cause damage until the temperature reaches about -50 F. -100 RV AF solidifies at about -60 F and protects down to about -100 F. If you properly drain the water from the block any small amount of water left will have plenty of room to freeze and expand and cause no damage, so you are protected to ANY TEMPERATURE. If you choose to refil the block with antifreeze after draining that AF will be diluted a bit and be slightly less effective, but probably not enough to make any real difference. So winterizing step #1 is DRAIN THE WATER FROM THE BLOCK. Step # 2 is whatever;)
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
71,133
Why does Mercury state in my owners manual "For additional assurance against freezing and rust, fill the cooling system with a mixture of antifreeze and water" If it is a boating wives tale?

Ayuh,...... It's called Marketing,.... Create a Market for after the initial sale,....

It keeps Dealers in business,....

If yer smart enough to Drain, any, 'n all water outa yer boat, 'n it's driveline, ya got nothin' to worry 'bout,....
Air, just Don't Freeze, atleast on this planet,.....

'n yer motor sees tons of sand, 'n debris all summer long, the rust is pretty much irrelevant in the equation,....
That's why ya remove the drain, 'n poke the hole out with a nail or deck screw,.....
I got a nice 3" ssteel deck screw in my boat workin' pail,... ;)
 

Merc4ever

Petty Officer 1st Class
Joined
Feb 14, 2009
Messages
232
Great video! Thanks a million I used it to winterize mine this year and it was a great help. Would it hurt to leave the antifreeze out if I get it good and dry and leave drain valves open to allow air to circulate?

You're welcome, I'm glad I helped somebody. I don't really think it would cause any major damage but like I said earlier my owners manual says: "For additional assurance against freezing and rust, fill the cooling system with a mixture of antifreeze and water"
 

Merc4ever

Petty Officer 1st Class
Joined
Feb 14, 2009
Messages
232
Ayuh,...... It's called Marketing,.... Create a Market for after the initial sale,....

It keeps Dealers in business,....

I agree when it comes to things like oil Mercury is guilty of that but I've never seen them push or recommend Mercury brand antifreeze.

Do they even make a Mercury brand antifreeze?
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
50,423
I agree when it comes to things like oil Mercury is guilty of that but I've never seen them push or recommend Mercury brand antifreeze.

Do they even make a Mercury brand antifreeze?

yes they do. Mercury part number [h=3]877770Q 1[/h]
 
Top