98' Sunsetter 5.7 "monsoon" winterizing question

[pnwsunsetter]

What's up everybody. I'm new to the forum, fairly new to owning a ski boat. Most of my boating experience is saltwater fishing. I searched for days and haven't found anything related to an idea I have for winterizing the engine on my boat. 

The craft in question is my 1998 Malibu Sunsetter direct drive equipped with the 5.7 Monsoon engine.

I have one of those cordless Milwaukee transfer pumps and I also have 10 gallons of automotive coolant. I know my way around mechanics pretty well as I used to wrench professionally. My question is, can I simply run my engine and pump coolant into it with the transfer pump using a garden hose exactly how I do after each day on the lake? 

 

Typically after each lake day, I take the time to "rinse" out the engine cooling system with water from the garden hose as there is a slick attachment for such that I installed inline on the main cooling line. This method would also allow me to attach my garden hose to the engine as I always do and use my transfer pump to force coolant into the garden hose and through engine as it's running. I would then Run it long enough to see visual evidence of coolant coming out of the exhaust. 

 

Would this idea work instead of going through the typical motions of draining everything? Just an idea. Thanks. 

[smileysteve]

51 minutes ago, pnwsunsetter said:

also have 10 gallons of automotive coolant.

This is a great way to poison some fish if not some mammals too.

You should use RV style coolant for your fresh water system. Ethylene is toxic and doesn't degrade well, vs ethanol and propylene are safer https://rvlife.com/techtipsrv-antifreeze-not-all-the-same/

It's also unclear to me how your proposed method is easier than draining everything. (I can drain everything on an inboard in less time than it takes to get the transfer pump from the garage). If your winter is long, it's not the worst to get some RV antifreeze in there to prevent corrosion, though.

[pnwsunsetter]

11 hours ago, smileysteve said:

This is a great way to poison some fish if not some mammals too.

You should use RV style coolant for your fresh water system. Ethylene is toxic and doesn't degrade well, vs ethanol and propylene are safer https://rvlife.com/techtipsrv-antifreeze-not-all-the-same/

It's also unclear to me how your proposed method is easier than draining everything. (I can drain everything on an inboard in less time than it takes to get the transfer pump from the garage). If your winter is long, it's not the worst to get some RV antifreeze in there to prevent corrosion, though.

Thank you for your reply. I apologize if I articulated my post in a manner that made it easy for a one to assume that I would simply release the coolant into the water during first startup in spring. I know better than that, and it would also blow my.mind to think people actually do that. I guess these days a person has to break every little thing down that they do in order to avoid confusion online. So with that being said I want to make it clear that I have containment methods in place in my garage to capture the coolant during startup in spring. A giant rubber inflatable splash pan similar to what you see race car drivers put under the race cars in the pits. It will hold dozens of gallons of fluids. It's called a best management practice containemt, or a BMP. 

 

As a new person to this forum, I'm just simply trying to gain some inside knowledge in regards to boating and maintenance therein. Thanks for your reply. 

[justgary]

If you routinely boat in salt water it may be best to convert your engine to closed cooling by adding a heat exchanger.  You would then run coolant full time through the engine block and not expose it to salt.  Winterizing would consist of dumping the raw water side of the heat exchanger and the exhaust manifolds.

It would also be a good idea to switch to stainless manifolds so you no longer have to deal with rotting out cast iron ones every few years.  The best way to hydrolock your engine is by ignoring the telltale rust ring around the riser bases.  The risers will eventually dump water into the cylinders as they begin to leak.

[csleaver]

From my experience you need to run the engine for at least 15-20 minutes while recirculating the antifreeze from the exhaust to the intake to prevent it from being diluted by the sea water already in the system.  It is easier to just drain the cooling and exhaust system.  Running the engine using antifreeze for a few minutes without first draining it will result in a very diluted antifreeze mixture that will provide very little freeze protection. 

[oldjeep]

4 hours ago, csleaver said:

From my experience you need to run the engine for at least 15-20 minutes while recirculating the antifreeze from the exhaust to the intake to prevent it from being diluted by the sea water already in the system.  It is easier to just drain the cooling and exhaust system.  Running the engine using antifreeze for a few minutes without first draining it will result in a very diluted antifreeze mixture that will provide very little freeze protection. 

Yup.  Cue the 2023 - I cracked my block after winterizing (wrong) thread 

Edited September 19, 2022 by oldjeep

[pnwsunsetter]

12 hours ago, justgary said:

If you routinely boat in salt water it may be best to convert your engine to closed cooling by adding a heat exchanger.  You would then run coolant full time through the engine block and not expose it to salt.  Winterizing would consist of dumping the raw water side of the heat exchanger and the exhaust manifolds.

It would also be a good idea to switch to stainless manifolds so you no longer have to deal with rotting out cast iron ones every few years.  The best way to hydrolock your engine is by ignoring the telltale rust ring around the riser bases.  The risers will eventually dump water into the cylinders as they begin to leak.

We absolutely do not put our Malibu in salt water. I failed to mention we are fresh water pleasure boaters only. Thanks for the information about the rust rings. Thankfully there are none on ours. 

11 hours ago, csleaver said:

From my experience you need to run the engine for at least 15-20 minutes while recirculating the antifreeze from the exhaust to the intake to prevent it from being diluted by the sea water already in the system.  It is easier to just drain the cooling and exhaust system.  Running the engine using antifreeze for a few minutes without first draining it will result in a very diluted antifreeze mixture that will provide very little freeze protection. 

Thanks for this! This is something I have no experience with! Didn't even think about the dilution factor. Also, I failed to mention we do not run our Malibu in salt water. The "rinsing" I spoke of in my OP is a habit I picked up during childhood. My dad always rinsed the engines out no matter if they were ran in fresh or salt water. 

7 hours ago, oldjeep said:

Yup.  Cue the 2023 - I cracked my block after winterizing (wrong) thread 

Definitely won't be happening 😂 

[pnwsunsetter]

So after reading the replies and soing more in depth research, I decided to break down and just pay to have it winterized at a local marine shop. Allowing someone else to work on my stuff goes against my better judgment, however this is uncharted territory for me and I feel like it's the best choice. The local shop told they will fog the engine. They explained it and it makes sense to me. I'll be changing the engine oil & filter myself as well as the fuel filters. 

I also have 10 (yes, 10) of those DRI-Z AIR things that I'm placing all about in the boat as well as a small fan and 40 watt incandescent light bulbs (trouble lights). 

My thought process is to over do it in hops of not missing anything. 

[lake4life]

If you don’t drain the engine then you will need to get it up to running temp before you circulate the coolant.  If you don’t get it up to temp so the thermostat is open then the coolant will not be fully circulated.  Best practice is to first drain then circulate the coolant, although some say coolant isn’t even necessary if you completely drain it.  For me coolant circulation after completely draining is cheap insurance.

[Bluefishcay]

One tricky place for the monsoon (vortex) engine is the driver side block.  There is a knock sensor and it needs to be removed to drain the block.  Not an obvious drain.  My boat has a cracked block due to not draining the block. 

[stonelx]

FWIW, I have a 2003 monsoon, and only drain the two sides of the manifolds, yes one is a knock sensor... a few hoses on the front around the impellor and near the transmission cooler, and the sync garden hose at the back of the engine. (Which just connects the two manifolds, not sure if the 98 has that hose)

I only run RV environment safe antifreeze through the heater core that sits underneath the dash (If you have a heater), and through the marine shower pump in the trunk. (If you have a shower)

Use an air compressor to flush the water out, and then add the antifreeze and flush that out.

I also just pour a cup of the RV antifreeze through the manifolds just to coat it. It then drains out into the bilge and then onto the driveway. 

After the engine has dried out for a week or so, I place both plugs of the manifolds back in to prevent possible corrosion of the threads. Paint on some copper anti-seize to the threads.

I'm in -35C winters.  

Original owner. 

 

Edited September 21, 2022 by stonelx

[IdahoAxis]

@pnwsunsetter- Random question, but did you recently purchase this boat at IWS? Super clean black & white Sunsetter LX? If so, that was my sister's boat. Great boat, hated to see it go.

[UWSkier]

There is a PDF somewhere that details this process on a Monsoon.  It's super easy.  Only part it misses is the heater core.