Question on Winterizing an MPI

[Tafflad]

Just changed my boat, first time I have had an MPI engine (4.3) with the single point drain down (blue wheel)
Previously when I have had boats winterized, they have left it with engine full of antifreeze, and removed the serpentine belt.

Had winterizing done on Friday by Mercruiser dealer, they just drained it down – using the single point Blue wheel, and left the Serpentine belt in place.
When I asked, I was told they got engine hot, then using the single point drain down on MPI, drain it and inside is left dry - so there is no need for anti-freeze.
Is this correct ? …. I had thought that anti-freeze also prevented any corrosion of block due to condensation with freezing temperatures.

Boat is dry stored in a boat shed.

 

[Don S]

Re: Question on Winterizing an MPI

Antifreeze is NOT required or needed, but used by SOME saying it prevents corrosion.

Using only the single point drain without checking to see if all the drains are clear to drain IS a problem.

 

[Tafflad]

Re: Question on Winterizing an MPI

On the single point drain ... I thought opening the Blue drain knob - drained all .... sort of following the name "Single point drain"

If this is not the case what else has to be drained down ?

 

[Don S]

Re: Question on Winterizing an MPI

That is how it's supposed to work, and it does ............. on paper.

Problem is, there is no way to verify each and every section that goes into that single point drain system is drained. You could have one side of the block plugged up with mud, sand, rust or whatever, and not know it. So it freezes, that one side still has water in it, and bingo, cracked block.
Even with the engines that had the multi point drain (all the plugs and hoses you had to remove) you still had to make sure the holes were clear after removing the plug. Usually done with a screw, nail or small screwdriver to make sure the water was out.
You can't do that with the single point drain.

 

[Tafflad]

Re: Question on Winterizing an MPI

You can't do that with the single point drain.

The Mercruiser agent did the job, so would expect in done correctly.
For my education ... what else would I need to do after opening the single point drain ?