Malibu M5 M6 winterization

[OtherBoatisaCessna]

Welp, I got it done today.  First time winterizing with anti-freeze.  For anyone wondering, it works just fine to use a bucket of antifreeze and the hose/water intake on the transom.  Super easy.  I first pulled all the drain plugs and dumped the strainer, put them all back on, closed the raw water intake valve (which took some time to find - for me it is in line on the main water intake going into the sea strainer, not visible from anywhere useful - had to feel for it with my hands), hooked up a six-foot garden hose to the transom and ran it into a bucket with about 5 gallons of antifreeze sitting on the swimstep, fired it up and ran it until antifreeze was chugging out the exhaust.  Very simple, bet I could do it all in less than 30 minutes now.  Thank you all for the help!

Oh, by the way - 70 hours on the boat this season exactly.  I feel pretty good about that!

[Sooner]

I have a ‘21 M5 and mine had all four drain plugs.  I took them all off, disconnected and drained the raw water strainer, and disconnected the ballasts. I’m in Oklahoma so wondering how necessary it is to run antifreeze through it.  

[hethj7]

I have never run AF and been fine.   The only reason I'd potentially want AF is for some corrosion protection, but I wouldn't be concerned about freezing if you drained all those points.   I've survived plenty of cold stretches in the midwest without using AF.   

Part of the reason I love these is that I can drain it all in a matter of minutes with zero tools required and be winterized.  

Edited October 21, 2023 by hethj7

[ahopkins22LSV]

3 hours ago, Sooner said:

I have a ‘21 M5 and mine had all four drain plugs.  I took them all off, disconnected and drained the raw water strainer, and disconnected the ballasts. I’m in Oklahoma so wondering how necessary it is to run antifreeze through it.  

 

2 hours ago, hethj7 said:

I have never run AF and been fine.   The only reason I'd potentially want AF is for some corrosion protection, but I wouldn't be concerned about freezing if you drained all those points.   I've survived plenty of cold stretches in the midwest without using AF.   

Part of the reason I love these is that I can drain it all in a matter of minutes with zero tools required and be winterized.  

I don’t use antifreeze on Michigan either. Never have since owning our first boat in 2013. Never have had an issue. 

[dlb]

31 minutes ago, ahopkins22LSV said:

 

I don’t use antifreeze on Michigan either. Never have since owning our first boat in 2013. Never have had an issue. 

First Malibu was a 2002 in Indiana, never used antifreeze then.  Twenty plus years later the story has not changed.

[peterT]

On 5/25/2021 at 8:41 AM, jcon44 said:

So I actually just spoke to my dealer today about the heat exchanger plug on my M5. I found out last fall when winterizing for the first time that I don't actually have that so I pulled that hose off to drain. I was also not fun. I asked them to add the plug when I there for other warranty stuff. Needless to say they didn't add it and I needed to speak to a few people before they grasped what I was talking about but when they finally spoke to a technician he confirmed some early M5s didn't have it.

What the tech said he does on all M5/6 is pull a hose from the back of the impellor housing and blow the water out the vdrive plug hole. instead of messing with the plug at the bottom, that I don't even have. I haven't looked to confirm which hose he is pulling but will take a look the next time I am on the boat this week to get an idea.

seems like it may help me out and save ya'll (you all) some knuckles..

has anyone else heard or done this?

 

I’m new to winterizing my own boat. Are there 4 blue drain plugs or 5 including the heater? I found 4 of them not sure if I need to do anything additional for the heater? 
Thanks in advance! 

[ahopkins22LSV]

3 minutes ago, peterT said:

I’m new to winterizing my own boat. Are there 4 blue drain plugs or 5 including the heater? I found 4 of them not sure if I need to do anything additional for the heater? 
Thanks in advance! 

The heater is apart of the closed cooling circuit from the block so there is no need to drain it. 

[peterT]

So do you have to do anything at all with the heater? 

[ahopkins22LSV]

4 hours ago, peterT said:

So do you have to do anything at all with the heater? 

Correct.

[platon20]

On 9/28/2023 at 11:02 PM, OtherBoatisaCessna said:

Welp, I got it done today.  First time winterizing with anti-freeze.  For anyone wondering, it works just fine to use a bucket of antifreeze and the hose/water intake on the transom.  Super easy.  I first pulled all the drain plugs and dumped the strainer, put them all back on, closed the raw water intake valve (which took some time to find - for me it is in line on the main water intake going into the sea strainer, not visible from anywhere useful - had to feel for it with my hands), hooked up a six-foot garden hose to the transom and ran it into a bucket with about 5 gallons of antifreeze sitting on the swimstep, fired it up and ran it until antifreeze was chugging out the exhaust.  Very simple, bet I could do it all in less than 30 minutes now.  Thank you all for the help!

Oh, by the way - 70 hours on the boat this season exactly.  I feel pretty good about that!

After you run the antifreeze do you take the blue plugs out again and leave them out during the winter?

 

[hethj7]

1 hour ago, platon20 said:

After you run the antifreeze do you take the blue plugs out again and leave them out during the winter?

 

I think that would defeat part of the purpose of running antifreeze and I would leave them in for corrosion protection.  
 

I just winterized today - no antifreeze for me, as usual. 

[Pilotguy]

This will be my first winter without using antifreeze. I have the M5 and my boat is kept in heated storage all winter as it has for the prior winters. 

1 hour ago, platon20 said:

After you run the antifreeze do you take the blue plugs out again and leave them out during the winter?

The last two winters I would run antifreeze through the heat exchanger and then pull the blue plugs draining the antifreeze. It varies person to person but this is what I was taught by the master mechanics at the marina I worked at and bought the boat from. 

[Cole2001]

A lot of techs run antifreeze as a failsafe in case any water gets trapped when draining. For whatever reason, sand, air lock or anything were to get in the way. 
Another reason why it’s good to turn the engine over with the plugs out to spit any remaining water. 

[SurfinLSV2021]

23 hours ago, platon20 said:

After you run the antifreeze do you take the blue plugs out again and leave them out during the winter?

 

 

23 hours ago, platon20 said:

After you run the antifreeze do you take the blue plugs out again and leave them out during the winter?

 

That's how I winterize my 2021 M5. Pull plugs and leave out until next season after filling with antifreeze.

[ahopkins22LSV]

14 hours ago, SurfinLSV2021 said:

 

That's how I winterize my 2021 M5. Pull plugs and leave out until next season after filling with antifreeze.

I’m struggle to understand this process. Doesn’t all of the antifreeze just drain out after filling since you are leaving the drain plugs out?

[dizzygti]

I winterized my M6 for the first time yesterday.   Super simple to do, takes longer to get to the plugs than to remove them.    Ended the "season" with 228 hours on the engine, not bad for first boat ownership!    

[platon20]

On 10/30/2023 at 7:31 AM, ahopkins22LSV said:

I’m struggle to understand this process. Doesn’t all of the antifreeze just drain out after filling since you are leaving the drain plugs out?

Yes I think so.  This year I just ran the boat for 20 mins on idle while using raw water coolant, then I ran 10 gallons of antifreeze into the engine after the engine had reached normal operating temp.  Then I just left the drain plugs in, instead of removing them.

I also have a temp controlled garage with a backup generator and a bilge heater, just for extra protection.

I think it's better to leave the drain plugs in after running the antifreeze thru the engine.

[csleaver]

There shouldn't be any significant risk of freeze damage on the M5/M6 engines during storage as long as the raw water drain plugs and strainer bowl are removed, and it is possible to verify that they have drained.  I would not normally recommend reinstalling the plugs and strainer bowl during storage with the newer plastic drain plugs, unless it is absolutely necessary.  Testing the coolant mixture with a refractometer is also a good idea to ensure the closed cooling system is protected to the proper level, depending on how cold temperatures are expected to be.  Concentrated coolant can be added and run through the closed cooling system for storage if required, depending on the freeze protection level needed.

The only advantage I have really seen by running the engine and pumping RV antifreeze into the raw water system is the ability to reinstall the drain plugs and check for leaks while still protecting the system from freeze damage during storage, instead of waiting for spring to install the plugs.  It can also dilute any raw water that may have been trapped in the system.

Even undiluted RV -50 degree F antifreeze can turn to frozen slush between 0 to 14 degrees, and may freeze solid at 0 to -50 degrees F without the risk of actual bursting damage to the cooling system in most cases.

[shawndoggy]

16 hours ago, csleaver said:

There shouldn't be any significant risk of freeze damage on the M5/M6 engines during storage as long as the raw water drain plugs and strainer bowl are removed, and it is possible to verify that they have drained.  I would not normally recommend reinstalling the plugs and strainer bowl during storage with the newer plastic drain plugs, unless it is absolutely necessary.  Testing the coolant mixture with a refractometer is also a good idea to ensure the closed cooling system is protected to the proper level, depending on how cold temperatures are expected to be.  Concentrated coolant can be added and run through the closed cooling system for storage if required, depending on the freeze protection level needed.

The only advantage I have really seen by running the engine and pumping RV antifreeze into the raw water system is the ability to reinstall the drain plugs and check for leaks while still protecting the system from freeze damage during storage, instead of waiting for spring to install the plugs.  It can also dilute any raw water that may have been trapped in the system.

Even undiluted RV -50 degree F antifreeze can turn to frozen slush between 0 to 14 degrees, and may freeze solid at 0 to -50 degrees F without the risk of actual bursting damage to the cooling system in most cases.

@csleaver, what's the disadvantage of reinstalling the plugs after draining?

[csleaver]

2 hours ago, shawndoggy said:

@csleaver, what's the disadvantage of reinstalling the plugs after draining?

The only issue with reinstalling the drain plugs while the boat is in storage is that any residual raw water in the system can no longer drain, but this is unlikely to cause a real problem.  When Malibu drains the raw water before shipping the boat to a dealer, they also leave the drain plugs out.  Perhaps, that is why it is also tends to be my preference. 

[amartin]

I am way late to updating the crew, but I now have a '23 25 LSV.  I winterized it a few weeks ago.  Took longer than it should have the first time to get a lay of the land and figure out where every thing was.  However, there was no way that the 4th plug was coming out, as it backed right up to a stringer.  I could get my hand on it, but because of the stinger and how far down it is in the hull due to the walkthrough, there was no way to grab it other than between 2 fingers, which obviously was not going to provide the torque required.  Other 3 plugs were a piece of cake.  I wasn't too concerned, as there was no cold weather in sight.

I took the boat to the dealer last week for some other warranty items and requested that they put the whip / drain hose on that fitting as was mentioned earlier in this thread.  I figure that they must keep a midget short person with really small hands on staff just for these occasions.  Low and behold, we have a pretty good cold snap coming so I figure that this will work out well.  I spoke to the service manager today to verify that it was ready for the cold and he told me that they no longer install the elbow / hose whip due to failures of the plastic elbow causing some over heating issues - this per Malibu.  He also said that the 4th plug down by the heat exchanger does not need to be pulled and that they are not pulling it on any boats that they are winterizing.  Any water in that section will drain when the V-drive plug is pulled.  He also said that malibu has been shipping them boats with that plug installed, but the other plugs not installed...  

Seems to me that if it wasn't needed that it would be more cost effective to remove the entire piece and just use hose?  Anyone else have any thoughts on this?  Below is a picture from the aft end looking forward at the 4th plug.  It took some contortion to even get a phone down there for the picture, so it is not nearly as accessible as it appears in this photo.

[BlindSquirrel]

Pretty sure that used to be just hose before they updated it and added that pug. At least on my brother's 2018 25LSV M6. I remember pulling that hose off when we winterized it. Which is what I would do on yours to confirm or disprove there is no water in there. It was not easy to get to, hanging upside down, but water for sure came out of it on his.

[klntime]

if worried you can always just disconnect hose from water pump, blow a little air, even with your mouth is fine, that will get any remaining water trapped out with vdrive plug removed.  Make sense?

[hethj7]

Yea, my 2019 didn’t have the plus.  I pulled the hose from the bottom of the heat exchanger and definitely got water out.   But perhaps, there is enough expansion space in the rubber hose after other points are drained it is okay.  
 

I would be skeptical as that isn’t what the manual calls for.  But, document the dealer direction and if it freezes, tell the dealer to expedite getting you back on the water in the spring.  I do think enough water comes out via other points that if damage occurs it may be to hoses and the exchanger and not to other major components.  But that is speculation.  

[hethj7]

7 minutes ago, BlindSquirrel said:

Pretty sure that used to be just hose before they updated it and added that pug. At least on my brother's 2018 25LSV M6. I remember pulling that hose off when we winterized it. Which is what I would do on yours to confirm or disprove there is no water in there. It was not easy to get to, hanging upside down, but water for sure came out of it on his. 

 

He had a 2018 M6?