Adding anti-freeze at strainer to winterize a closed cooling system?

villain style

villain style

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Oct 10, 2006
1,710
Safe Harbor Marina Kent Island, MD
Boat Info
2006 44 DA
QSC 8.3s
Engines
Cummins QSC 8.3s 500HO
On a 1995 5.7L with closed cooling, and specifically just asking about adding the anti freeze to it for winterizing the engine, not the rest of A/C, Generator, water systems, etc...If I was to add anti freeze directly into strainer with engine running until it comes out of exhaust is that sufficient? Also, assumes I fog carb once I see A/F come out exhaust... Would that do it?????

Thanks....
 
question...... is the boat in or out of the water ?

In the water......make sure your seacock valve is closed.....add pink thru the top of the strainer.........and fog at the same time. I usually run fresh water thru the strainers for a while to flush the coolers then pink.

You should be fine.
 
that should do it. also, once out of the water open seacocks since the last sectin of the hose probably did not get pink, or pump that section of hose out and put in some pink.
 
Thanks for the replies. The boat is lift kept so am able to remove hose either at raw water intake or strainer to feed A/F there...... I was getting some input to open drain plugs at heat exchangers and riser/manifolds to drain water before adding A/F at strainer and was confused as to why that would need to be done???
 
Only thing I would add is make sure you have a large enough resevoir or funnel to feed the strainer and engine. Your going to be amazed at how fast it will suck it through. For instance we use 3 gallons to run through the genny and another 3 gallons for the A/C system. Maybe overkill but better to be safe than sorry.
This year I made large resevoir out of a 5 gallon bucket. I added a valve to the bottom and a section of 3/4 hose on the end of that to feed the raw water hoses on the necessary system being winterized. If you make something like this just make sure the inside diameter of everything, valve and hoses, is large enough to provide proper flow.
Good luck!
 
If yo dont have a service manual..get one. Know the difference of the cooling system. Even tho you may have closed cooling, there si still that portion of raw water cooling that feeds to the risers and the heat exchanger for closed cooling.
The two systems differ and know which plugs drain the right ones. You need not drain the closed section for winterization if properly protected with antifreeze.
As for the raw water cooling sytem protectin for winter. you can drain the system as manufacturer suggests and some owners will just connect a bypass off the outdrive inlet or in you have inboards with strainer, make a bypass off the strianer.
In the past when I had 7.4L, I/O, I bypassed the outdrive inlet and made a make-shift reservior for winterization. I used a 5 gallon painters bucket, 1-1/4 inch fitting off the bottom of bucket and hose to the engine bypass. My engine would be previously brought up to temperature, know the capacity of the system and then open the valve. Once I used the entire reservior I stopped the engine. This method saved me alot of mechanic dollars and when I saw a freak 70 degree day in December, I didnt hesitate to take the boat out and then winterize it again.
It worked for me for over ten years this way. Now I take the easy route my current 2003 engines have a blue plug system and air release drain system.
 
The theory behind draining the water from your blocks and even pulling the little screws on the fiberglass exhaust units is to get as much water out so that the anti-freeze is going through at 100% rather than mixing with water and then exiting...you would see pink coming from the side of the boat but it would be a diluted solution.

Here is what I do:

Step 1: run engine to temp to get oil warm
Step 2: change oil and filter
Step 3: close seacock
Step 4: drain exhaust/and block
Step 5: run engine with pink stuff going into strainer

Also, I only lay up from Dec thru Feb/Mar with some use during the winter. Even so I have spoke to several Merc Product Managers and Customer Support Techs at in-service events like Yacht Expo and it has been explained to me that the added step of fogging the engines for this short amount of time (I would always dump a little 2-stroke oil into the fuel filters and run the engine for a little), is not required and would not be harmful if it were skipped. I am not advising that this is what anyone does as I am not a pro but I am letting you know what I do/have done for years.
 
My process has been to first shut off the fuel. That requires removal of a wire on the bulkhead fuel solenoid, because the knob on mine changes from auto to on.

The fuel filter is removed and refilled w/ half engine oil / half fuel.

The engine is run until it dies from fuel starvation. Near the end of that process I fog the air intake w/ the flame arrestor removed.

Once the engine has died I stick the intake water hose into a bucket of anti-freeze and use the starter to crank four gallons through the engine. The strainer is drained first and filled w/ anti-freeze too.

This way works for me 'cause I don't have to worry about timing the end of anti-freeze w/ the end of fuel.
 
For start-up in the spring I use the Mercruiser computer tool and the Mercruiser fuel pressure tool to turn the fuel pump on and bleed air from the rails.

This is soooo much better than cranking and cranking and cranking to purge the air 'till it starts. It is easy too.
 
Also, prior to all this I stick the raw water intake hose into a 5 gallon bucket of fresh water.

The engine is run w/ a garden hose filling the bucket while the engine drains the bucket. The engine always wins, so I shut down, wait for it to fill and re-start, to flush the salt water and warm the engines.

The oil and filter is also changed while the engines are warm.

The fuel filters are replaced in the spring when commisioned.
 
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