Mercruiser 5.7 winterizing question (about petcock)

[Danny Troy]

Today I winterized the 220DA I just bought, and removed the two upper blue plastic petcocks. I was able to loosen the port side lower brass petcock, and drained quite a bit of fluid from it. When I attempted to loosen and drain the starboard side lower petcock it wouldn't budge. I didn't want to force it for fear of breaking it off in the block. Is draining one side sufficient? I filled the engine with pink AF, so I'm thinking it should be ok. Any thoughts?

 

[Larry]

If you are sure your T-stat was opened or removed and you got about 5 gallons of anti freeze through the motor you will be fine. I never would open the pet cocks on my raw water cooled motors only because I knew I would be snaping one or creating a leaking one down the road, If you are getting 5-6 gallons of anti freeze through you are fine, it will flush out any water left in the motor.

 

[Danny Troy]

Good to hear that. And yes, I did warm it up enough to open the thermostat, and put in almost 5 gallons of anti-freeze. It was coming out of the outdrive "pink" qute a while before I shut it down, so I'm sure it's all anti-freeze in there.

I was just contacted by the prior owner and he said that he did loosen both lower petcocks to drain water, but I hear you about causing a needless potentional problem down the road. If I ever snapped that lower petcock off in the block it would be quite a job getting the remaining bit out to put in a new one.

 

[sr330daguy]

Humm I'm not convinced that this method is safe.How can one be convinced that the "pink stuff "displaced all the water in the block and manifolds?It may be diluted.Just my 2 cents.

 

[Larry]

All the passages in the block and the manifolds create a conduit, there is no pooling of fluids when the engine is running, it is like pouring the anti freeze through a hose. I am not saying that it doesn't mix a little at first but if you get at least 5 gallons through the motor you can be sure that you got anti freeze everywere that it needs to be.

 

[Canuckohio]

I have a 300 Sundancer with twin 5.7 on the North Coast ( Lake Erie). For winterizing , I just make sure that the pink antifreeze is all they way through the system and the engine was warm enough so the thermostat was open. I then spary some fogging oil in the carbs bit by bit so internal parts are coated and then kill the engine. Most of my friends with similar boats do not drain the manifolds, but make sure that there is plenty of antifreeze throughout the engine and drive.

 

[Danny Troy]

Yes, I'm trying to figure out why so many recommend draining, if it's filled with antifreeze. I would think there would be less chance of corrosion if it's filled with antifreeze, and air can't get at it.

On the other hand, the Seloc Mercruiser manual recommends draining, but doesn't mention antifreeze???

 

[Weave]

Drain and THEN fill with antifreeze.....You want to poke around the petcocks too....Soooo much scale and sediment could have blocked some of the water from draining....Trust me, you would be surprised how much can be blocked.
Just my 0.02....It's a LONG winter to spend worried.

 

[Daddubo]

When you say you are filling the engine with Pink are you running the engine and putting through the lower unit and circulating it, that is the only way you can make sure you have complete protection. If you are just some how pouring it in you aren't getting through the whole engine, heat exchanger risers and lower water pump hose. The thermostat will close on you before you could get the Pink through it. Pink is like premixed antifreeze if you add any water to it like what would be in the engine you will raise the freezing point.
I generally use automotive antifreeze because it does have anti corrosion additives in it but I drain the water first. The only way you will be sure you have enough antifreeze in it at the right strength is to drain some out and test it but I 'm not sure if it test the same as glycol if not put it in your freezer and see what happens.
With the petcock you can try to heat the block up with a propane torch and try to take the whole petcock out and then replace it with a ball valve and plug then you will never have to worry about it not opening but you will still probably have to poke it it break up the scale. That is my $.02 .