winterizing question

[kbryant]

Hello,
I have a MerCruiser 2011 4.3 MPI. I live in Northern WI. Question, After I get all the water out of the block do I leave antifreeze in the block over the winter or drain that as well ?

 

[Scott Danforth]

Hello,
I have a MerCruiser 2011 4.3 MPI. I live in Northern WI. Question, After I get all the water out of the block do I leave antifreeze in the block over the winter or drain that as well ?

I personally left the AF in the block over winter when I lived in the land of beer and cheese. however that is up to you. technically, drained = winterized as air doesnt freeze (assuming the last thing you did was drain after all the other pre winter items such as oil change, gear oil check ,drive alignment check, etc.)

Antifreeze will prevent any rust build-up. Assuming you are using -100F PG and not the -50F RV PG

 

[kbryant]

I personally left the AF in the block over winter when I lived in the land of beer and cheese. however that is up to you. technically, drained = winterized as air doesnt freeze (assuming the last thing you did was drain after all the other pre winter items such as oil change, gear oil check ,drive alignment check, etc.)

Antifreeze will prevent any rust build-up. Assuming you are using -100F PG and not the -50F RV PG

Thank you very much for the info. I appreciate your time. I think I would like to leave the AF in the block just to keep the rust out.

 

[Scott06]

Hello,
I have a MerCruiser 2011 4.3 MPI. I live in Northern WI. Question, After I get all the water out of the block do I leave antifreeze in the block over the winter or drain that as well ?

From two different people on this site you will get three different answers.

Some leave PG antifreeze with corrosion inhibitors in there to prevent corrosion of water jacket. Others like my self (upstate NY) just drain it and be done with it. I do chase the hoses with a little AF to get any residual water out but leave it dry.

The issue people run into is when sucking up the cheap pink stuff RV AF (this is not PG it is mostly alcohol) they dont drain the block first and the cheap AF gets diluted.

Where marinas have huge revesiors/tubs of PG and are checking the concentration of PG while running the engine for long enough time to get all the water out and mixed with proper strength PG this is great to leave in the jacket and what merc now reccomends.

our boats have lasted 33 years, 25 years , and now 30 on the current one just draining ... other than a like surface rust there is no scale in the jacket.

 

[kbryant]

Thank you for taking the time to reply. I appreciate the information

 

[youmansjason]

I prefer to drain it fully and flush with a little propylene glycol based anti-freeze (not the cheap RV stuff) to make sure all of the water is out, and then I fill the block with propylene glycol for the rust/corrosion protection. The cost difference for propylene glycol based anti-freeze is insignificant compared to major engine damage (and gives me peace of mind all winter).

I do live in the south (North GA), but we still get several days in a row with below freezing temps and I've never had an issue.

 

[Grub54891]

I use -100 for mine. Drain all water, hook up muffs, at times I use a pump for running it through as some boats have the motor mounted water pump and those don't prime well on just a hose. On my little 3.0 I simply drain as it's easy to get all the water out. I leave the -100 in as it's fine in there. Never froze a block and have done hundreds of them over the years working at a marina.

 

[crazy charlie]

Hello,
I have a MerCruiser 2011 4.3 MPI. I live in Northern WI. Question, After I get all the water out of the block do I leave antifreeze in the block over the winter or drain that as well ?

Drain the manifolds and risers prior to draining the block.After draining the block fill risers and manifolds with AF and fill block with AF.This is more difficult, time consuming and more expensive than just draining but it is the best possible care you can provide to your engine.Charlie