engine drain plug

[rreale]

I started my boat yesterday in my yard with the muffs. its a mercruiser 454. after about 45 seconds i saw a water leaking into the bilge.

i found a hole above the starter. and found a brass plug in the bilge.

any reasons why this could have come out???
i didn't see any other leaks. can i damage the engine running it with a plug missing. The other 3 are in.

can i just order a new plastic one.

any other ideas/help would be appreciated.
I have had the same guy winterize my boat for the last 9 years. no problems ever.

 

[imported_TheMan]

Re: engine drain plug

If you are talking about the brass cap looking object, that is one of the core ("freeze") plugs. Do some searches and you will see from Don S that they are not designed to prevent freezing and are just an artificat from casting.

Anyway, if that is what you found you could have freeze damage to your block. Its also POSSIBLE, but unlikely, that the thermal expansion changes could allow it to pop out. It takes a lot of pressure to install them... and quite a bit if pressure to pop them back out.

Now if you found a threaded piece, that might just mean the drain plug was not replaced and you have to reinstall it.

As far as damage.. if you don't have water staying in your block, then you don't have adequate cooling and could have all sorts of problems (warping, burning, etc). Running for a short time (minutes) you might be okay.

So did you find an actual core plug or a drain plug?

 

[rreale]

Re: engine drain plug

a core plug. it was brass, about 1.5 to 1.75 inches in diameter.


i will check the oil to see if there is any water in it.
what else should i check for?

 

[imported_TheMan]

Re: engine drain plug

In all honesty you should have the entire block disassembled and checked out. If the plug popped out due to freeze damage and improper winterization, you could have cracks in everything (heads, block, intake manifold, exhaust manifold). Only way to know for sure is to check.

Now, me being not the most cautious person in the world would probably replace the plug and run it. Like you said, check for water in the oil. ALso, do a compression test to make sure the heads are sealing and you don't have any cracks in the cylinder walls. After you verify that, run the engine for a while. Check the oil again for water. Then check your spark plugs for any steam cleaning. Make sure you don't see any water dripping from anywhere too...

 

[Gary H NC]

Re: engine drain plug

Take the old core plug to Napa and get the rubber replacement.
It will work for now until you find out if you have other leaks or damage.

 

[rreale]

Re: engine drain plug

i checked the oil (via the dipstick) about 18 hours after running it. i didn't see any evidence of water. the oil looked the normal new oil color not foamy or cafe latte like.

i will be towing it back to the dealer that winterized it. hopefully he will stand behind his work. i have a receipt.

 

[Bondo]

Re: engine drain plug

I have had the same guy winterize my boat for the last 9 years. no problems ever.

Ayuh,... I guess that's no longer True,... Hopefully no other damage occurred....

The Only explanation for a coreplug in the bilge is Freezing, with Water...

Good Luck,+ Welcome Aboard...

 

[rreale]

Re: engine drain plug

What type of questions should i ask my mechanic when he checks it over. I assume he would do a compression check. does he need to test each cylinder. any other tests he should do???

 

[Bondo]

Re: engine drain plug

Ayuh,... I would think Pressure Testing the cooling system would be the 1st order of business...

 

[rreale]

Re: engine drain plug

My mechanic looked at it and says there are no problems. he mentioned that the block would crack on the opposite side of the plug that blew out

he says he will just push the plug back in. He thinks the problem started because I left the boat in the water too late last year. i looked at the historical weather data and it was cold. some days stayed below freezing all day last november. He said he thinks wind blew in blower vents and froze the water and pushed the plug out a little bit, but not all the way. when he winterized it with the anti freeze solution he didn't notice any leaks. he said during the winter with the cold temps, the plug go pushed out.

I know i left the boat in awful late last year. there were still some on the lake when i took mine out. i always thought i was protected because the water was till warm (45-50 degrees). but maybe not. he says if you want to leave it in late, to tape up the blower holes, when its not in use.

 

[imported_TheMan]

Re: engine drain plug

If your mechanic is fully competent, then great! Looks like you've avoided any problems.

When he "looked at it", what did he actually do?

I'm also curious why he said the block would crack on the opposite side that blew out. Are the wall thicknesses any different? And what about internal damage that is independent of pushing out a plug.

 

[rreale]

Re: engine drain plug

not sure what he did. he says he has seen this many times.
the other day a friend of mine told me the same thing about a crack on the opposite side. the mechanic said he didn't see any. he also said no need to do a compression test, everything is fine.
he knows everything about boats. you can explain your problem to him and he always has a answer. he seemed to blame the problem on me for leaving the boat in the water too late.

 

[jam1ej20]

Re: engine drain plug

On saying that the block will crack on the opposite side is only assuming that the "freeze" plug saved the side that it popped out of, thereby cracking the opposite side since it stands to reason that both sides actually froze yet only one side was "lucky" enough to push the plug out. This is flawed logic and you could still have problems and cracks internally. Get a second opinion.