Trojan Boat Forum

The marine service guys "cannot proceed with any more work" for summerizing my engines because a frost plug is rusted on the starboard engine.

I don't know why they can't just charge me for the replacement and continue but that's besides the point of this post

I did find this thread about using some rubber replacements which seems like a good idea and might minimize future rust issues viewtopic.php?f=1&t=3819&hilit=frost+plug

But I don't even know what a frost plug is or how many there are or where to find it / them

Would any of you be so kind to point me in the right direction? Mechanics is not my strong suit but I'm trying.. so please explain it like I'm 5. I will not be offended

Chrysler 250s is what my survey says the twin engines are so I hope that's correct (bonus question: how would I confirm that anyway?)

TIA!

Rubber frost plugs are ok but IMO best suited for emergency repairs or even get you through the season. But many use them as a permanent repair. Brass plugs are the best. Getting the old plugs out and new ones in can be a real challenge. Engine removal is needed sometimes.


Frost plugs are on both sides of the block on the back behind the flywheel and on the front. Also on some heads.

The point of a "freeze" plug (I think that's the more common term) is to pop out when water inside the engine block freezes. So, it's a relief point, hopefully keeping the block from cracking. They are just round metal discs around the size of a 1/2 dollar tapped into the block.

They really are casting plugs or in my link core plugs. But they may save you in cold weather.

https://en.wikipedia.org/wiki/Core_plug

prowlersfish wrote: ↑Thu May 13, 2021 6:08 pm They really are casting plugs or in my link core plugs. But they may save you in cold weather.

https://en.wikipedia.org/wiki/Core_plug

Prowlersfish also hates it when people call the flat plate above an outboard prop an "anticavitation plate." Back to your plug. How rusted is it? Is it leaking? Is it accessible? Any progress on the matter? A picture of said plug might also get you some more ideas, but if a bona fide mechanic type said it is an issue, a replacement plug is probably in your future. Good luck, and please keep us updated.

P.S. I hugged my laptop when I saw that you searched the forum before posting your question. You'd be surprised how may people post questions that are already answered in a sticky.

I do call the freeze plugs a common slang. Just was saying why they really are there. They only save the block in freeze if your very lucky.

And good luck going into a parts store asking for a casting plug. You will get a deer in the headlight look. ask for a freeze plug your good.

I have 2 to replace on my starboard engine block today. The result of improper winterization. They are 1 5/8” plugs. It is not recommended to drive the plugs in striking the inside of the plug (using a socket) because of the possibility of distorting the plug resulting in leaks but because of their location that may be your only option without removing the engine. I have a set of drivers made for freeze plugs that I bought years ago from SnapOn or MAC tools. It has a long handle with a bend about 2” from the end. There is a ball on the end on the handle and a threaded ring holds the appropriate size driver in place. With the bend in the handle and the ability to position the driver at an angle on the ball I have replaced some that were in bad places but that was on cars and pickup trucks on a hoist. I may opt for the rubber expandable ones before I finish. If you use a sealant avoid products that set up hard. You don’t want to glue the plugs in place or they won’t come out if you do have a freeze situation. I normally use #2 Permatex sealant.