Engine Freeze?

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bcatlin

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Hello all - I haven't logged onto BoaterEd in a long while, however this afternoon I found an issue with my boat and, well...this is the first place I thought of for help.

A few weeks ago I pulled and winterized my 4.3l Mercruiser. I ran antifreeze through the muffs and used at least 4 gallons to ensure that antifreeze was in and water was out. After some recent freezing temps nights I went out to cover her before the snow starts falling. I reached in to check the engine and squeezed one of the water intake pipes and it is frozen. I can't squeeze it. I disconnected the pipe and it smells like antifreeze but seriously, the pipe is frozen at the lower elbow. The end I removed is 'crystalized' as I would expect.

Now I'm worried. Did I winterize correctly? I've done this method for years without issue and to be honest I wouldn't normally check on it after winterizing.

Any advice? Anything I can do? Should I worry?

Thanks!
Bcat
 
Did you run the engine long enough for thermostat to open, before you can link through it?
 
Same engines here. I only winterize by draining the engine (5 blue plugs) removing, 1 at a time, the 4 hoses attached to thermostat housing (top right & going clockwise, but doubt that makes a difference) fill each hose with at least half a gallon of antifreeze with large funnel, total of 2 gal/engine. Anything else in the engine is just air. 20 years with this boat; 22 with prior boat, and 6 with my 1st. Never a problem.
 
Thanks Guys! I'm pretty sure I ran the engine long enough for the thermostat to open (fingers crossed).

I think what I will do is defrost the engine slowly this week and drain the contents and refill with antifreeze...so I can sleep at night.

Thanks again,
Brian
 
Personally I would not do it that way. It is risky on a raw water cooled engine. I don't understand why people do other than they don't have to stretch to reach the engine drains. You are counting on the stat opening far enough long enough to get the raw water out of the engine. Keep in mind that the thermostat acts as a gate valve, it allows water to leave the engine when the water gets hot enough to open the stat. When you start the engine when its cold, you have water coming in that's cold, it doesn't open the stat because there is no load on the engine, so it all goes out the exhaust. The stat may or may not open enough for raw water to exit the block. So for example if the engine has a 160* stat, if the temp gauge is below 160 you can be pretty sure the stat is not open but even if it is at 160 it does not mean its open far enough to allow all the raw water out of the engine (approx 3.5 gallons). That's why its risky.

You are better off pulling the plugs, rod them out so they drain (there's a few gallons of liquid in a 4.3) disconnect the bottom end of the big hose from the stat housing to the circulation pump let that drain...drain the manifolds...and disconnect the raw water intake hose at the stat housing, point it down so it can drain.

After it has all drained and you poked all the holes to make sure rust flakes don't clog the drains, you can back fill with antifreeze if you want. But proper draining is all you need to do to prevent freezing. Adding AF just reduces corrosion. Not a substitute for draining.

And I don't like either -50 or -60 if your temps get down to or below zero. They both slush up and get hard then. Put a gallon in a freezer set at zero or a little below and see what happens, yes it does not expand but I would not want that in a cast iron engine at zero degrees F. I use either -100 or I mix up some Sierra no tox PG antifreeze with freeze protection down to -26*F if mixed 50/50 with water.

Those winterizing kits can be used on an engine with closed cooling as long as the flow is pressurized to avoid wearing the impeller, since sometimes gravity is not enough vs water pressure from a hose. But I feel they should NOT be used on raw water cooled engines! And I don't believe you will find that procedure in factory shop manuals. They will say to manually drain, poke the holes and back fill with AF.
 
I agree with Lou, it’s exactly what I do and never had a problem. I do add antifreeze and then drain it out as an extra precaution, but it’s not required. I feel better knowing that there is not water hung up somewhere in the motor.
Jim
 
Remember you have to understand how raw water cooling works. In a raw water cooling system you actually have excess cooling capacity. So, the way its set up, the excess cooling water is dumped out the exhaust, and the stat opens as needed, to keep the engine close to the opening point of the thermostat. What builds heat in the motor is load, and idling on the water hose, there is not much load. So it may not open enough and you get either no antifreeze in the motor or a weak antifreeze/water mix. Don't be mislead by the fact that marinas do it this way, they use a trough and keep recirculating the AF to keep it hot enough, to make the stat stay open. If you are stuck on doing it this way, try this: crack open a block drain into a paper cup and put what comes out, in the freezer set at zero. See what happens.
 
Guys, it only takes a few minutes to remove the T-stat. When you go that route, no need to worry if it is open or not.
 
Hi Guys! Thanks again for all the input! I'm happy to see BoaterEd is still the place to come for some great opinions.

I have taken the advice here and re-winterized my 4.3l. Pulled the plugs, drained everything (water/antifreeze) replaced the plugs and filled with -50 antifreeze. Hopefully that covers it for this year. Next I will just pull the plugs from the start.

You've also answered another question that arose from me replacing the plugs...one broke off as I was tightening it (I will get all new plugs in the spring). So when I poured the antifreeze in, it drained back out though the broken plug. I will not worry about this over the winter and just leave it dry and like I said will replace all next spring.

Thanks again,
Brian
 
Pretty hard to break those blue plugs! While you're ordering new ones, make sure you get a few extra 'O' rings.
 
quote:
Originally posted by bcatlin

Hi Guys! Thanks again for all the input! I'm happy to see BoaterEd is still the place to come for some great opinions.

I have taken the advice here and re-winterized my 4.3l. Pulled the plugs, drained everything (water/antifreeze) replaced the plugs and filled with -50 antifreeze. Hopefully that covers it for this year. Next I will just pull the plugs from the start.

You've also answered another question that arose from me replacing the plugs...one broke off as I was tightening it (I will get all new plugs in the spring). So when I poured the antifreeze in, it drained back out though the broken plug. I will not worry about this over the winter and just leave it dry and like I said will replace all next spring.

Thanks again,
Brian

Click to expand...


what's the coldest that you get in your climate?
if down to zero then the -50 or -60 isn't recommended but the -100 is. Take a look at West Marine's antifreeze guide....
 
I winterize only after running the boat from my marina to where I winter store, about a mile away. I know the stat is fully open by then. I shut off the water main and add 4 gal of -100 in the strainer. Everything is winterized; raw water pump, trans cooler, and engine before the boat is even lifted out of the water. The boat is pulled into the slings with dock lines. I then still pull the blue plugs just to be sure there isn't some pocket of raw water somewhere.
 
Thanks again everyone!

The head of the blue plug literally snapped as I was snugging it into place. I've ordered 5 new ones and will replace them all in the spring.

Take care and stay healthy!
Brian
 
I might consider holding finger over the hole in the blue drain plugs and proceed to fill the engine with antifreeze. It will mix with any water in pockets. Then take your finger away and let what drains out just drain out. Any pockets of water are gone which is what you worry about when just draining the block for winter.
 
True that will work, order some of the metal drain plugs and coat the threads with Merc perfect seal or Evinrude gasket sealer or even Permatex Aviation sealer and install them. If you leave the plugs out over the winter the threads can rust. So I'd replace em. Plastic plugs were not one of Merc's better ideas.
 
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