Replacing Freeze Plugs

[Shank85]

Greetings,

I've been getting my '94 Sport Nautique ready for summer and had changed the oil, replaced the impeller, and put all the plugs back in. I fired it up with a fake a lake, and noticed that there wasn't any water coming out of the exhaust. I quickly shut it down, fearing that I had messed up the impeller installation process. I took the impeller back apart and it had been getting water and was still in good shape. I started it up again, and still no water out of the exhaust. I again only let it run for about a minute, maybe two at the most. Once I was able to get a second pair of eyes on the engine compartment, we noticed water coming out of the engine block. Two of the freeze plugs had popped out. We winterized it, but probably not as well as we should have. With all that said, I'm having trouble figuring out how to tap in the new plugs. I bought two new brass plugs. They aren't as shallow as the ones that popped out, but I don't think that will be too much of an issue? The angle of the engine and the area I have to work with have me scratching my head. Ive read in other posts that a socket with an extension can work. Any other ideas? One of the other issues is that the one plug is directly behind the right forward motor mount, and is even harder to get to. Other questions related to this: There seems to be a debate on whether or not to put any kind of sealant on the plugs before installing them. Lastly, is there anything else I should be concerned about after having run the engine a few times with the plugs out? I appreciate all and any help. Thank You!

[hal2814]

As far as access, you may have to pull the engine or at least lift it and get the mount out of the way. There’s a fair chance you have more problems than the plugs themselves. Those plugs are used for casting, not freeze protection. You can get some rubber plugs that are easy to install to check the rest of your engine is running properly. That’s not a permanent solution but I’d do that before investing a lot of time in getting the brass plugs in. You may end up pulling the engine anyway. You don’t need sealant for the brass plugs unless they’re not a tight fit. Some people use sealant anyway. That’s fine but you’ll get a bunch of different opinions on what kind. Good luck! Hopefully you were just on a hill or something and it’s just the water in that part of the water jacket that froze.

[Shank85]

Thanks for the detailed response! I’ll plan to get some rubber plugs then and just run it like you said. If I learn anything new I’ll follow up and post it on here.

[Nautiquehunter]

hal2814 is spot on that is exactly what I would do it . After you get the freeze plugs sealed run it and keep checking the oil for water it will look like a chocolate milkshake if water mixes with the oil also watch the temp gauge for over heating. It is possible there is no permanent damage but you will be very lucky.

[Shank85]

Today a friend and I put a rubber plug in the "easier" freeze plug hole, and we were actually able to get a brass one in behind the motor mount. It wasn't pretty, but with a socket extension and smaller than ideal socket, we were able to get the brass one in. The motor mount actually assisted in being able to hold the extension in place while we hammered on it. Initially it did leak after installing it, but with a little extra tapping, we got a tight seal on it. Ran it up, and water was coming out of the exhaust, and the temperature stayed cool. We are going to try and drop it in the water tomorrow and take it for a spin. I'll let ya know how it goes.

[Nautiquehunter]

Good deal maybe you got lucky.

[hal2814]

That’s encouraging. At this point I’d do compression and leak down tests and then take it on the water while stopping periodically to check the fluids.

[functionoverfashion]

How long did you run it on the trailer? I'd let it run for quite a while, maybe 20 minutes at a time, check the oil, then another 20 at least, check the oil again. Just to be sure, before going on the water. A small crack can take a while to make a milkshake out of the oil.

[Shank85]

We took it out on the water a few days ago and she ran great. It was very concerning though. We were getting really hot water that was pooling in the hull. Could not spot anything coming out of the engine and it seemed to be originating up in the bow. We went out the next day and discovered that the heater core up front had cracked. I forgot we even had one as we really don’t use it. We capped the inlet and outlets from the engine and now it’s all good to go. Bad part is the hot water also fried the bilge. I’ll never half *** a winterization again. I really didn’t think I did, but I obviously didn’t do something right.

[functionoverfashion]

Heater cores are pretty sensitive, yeah. They're like a canary in the mine, if your boat gets too cold the heater core seems to always be the first to go. If you got away with a cracked heater core and fried bilge pump, you are very, very lucky indeed. Keep checking your oil, but it sounds like you might be in the clear.

Cheers!

[charlesml3]

For sure the heater core. Those will freeze very easily. The metal in the core tubes is very thin (it has to be) and it doesn't take much to freeze and split them. Pull it out and install a new one. Should be fine.

You should consider yourself extremely lucky. That engine froze hard enough to eject the casting plugs. Usually when that happens you have a crack in the block somewhere.

-Charles