Winterizing question on my newer 4.3L MerCruiser

mtcaves

Cadet
Joined
Jun 17, 2008
Messages
20
I have a new motor that was installed last year. I bought the boat this year and the guy who I purchased it from said make sure you pull all 5 plugs on the engine. There are five. One each on the manifold and one on the from below and to the right of the water pump and two on the block both left and right. They are a blue twist off type of plug so no tools are required. I thought about dumping some RV antifreeze in from the top down. Should I put the plugs back in and then put some RV antifreeze in it?

The engine is a 4.3L V6 I/O Manufactured in 2007

Thank you for any help.

Allen Caves
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,187
Re: Winterizing question on my newer 4.3L MerCruiser

Allen, I recommend filling the block and manifolds with straight automotive antifreeze. My 4.3LX always had residual water in the block and mannys after they finished draining. I dumped a little AF into each hose and waited for it to appear at the drain, and then replaced the plugs an filled it up.

Also dump some AF down the raw water intake hose and watch for it at the raw water intake on the outdrive. Recover the AF next spring and save for reuse. You will need 4.5 gal or so.
 

180shabah

Rear Admiral
Joined
Mar 26, 2005
Messages
4,995
Re: Winterizing question on my newer 4.3L MerCruiser

A little residual water is of no concern. With all of the empty space in the block it has room to expand without damage.

When you drain, don't forget to probe the holes for rust scale.
 
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