Do pushed out frost plugs mean cracked block ?

[jimmoe]

I'm thinking about buying an '87 Starcraft 19' w/a 4.3L omc with the following info regarding the engine...

"He was able to shift the boat manually so there is no outdrive or gear problems. He also found that the frost plugs on the side of the block were blown out the side from freezing at some point. With how the motor sits in the boat it is impossible to tell for sure if the block is cracked or not, but there is a chance it is. There was no water in the oil, so it is possible that it is just the frost plugs, but there is really no way to know for sure without taking it out and inspecting it. The boat is currently winterized, but I do not have the time, money or space to try to fix it or look further into the motor issue."

I realize we could use more info like "has it been run that way?... if so, what did exhaust look like?...was the coolant level low at the time?.....was there oil or coolant in the bilge below the motor?....

I thought I'd pose a question while waiting for the addtn'l info.

My question is....if the block was cracked, wouldn't there definitely be water or coolant in the oil even if it had not been run in that condition ?

 

[Scott Danforth]

Re: Do pushed out frost plugs mean cracked block ?

they are Core plugs, not frost plugs. they are to remove the green sand from the casting process.

if you have had freezing to push out a core plug, you should pressure test the block, you will most likely have a crack. if you dont have a crack, consider it time to buy a lottery ticket.

with a small crack, you may or may not have a leak

 

[jimmoe]

Re: Do pushed out frost plugs mean cracked block ?

Thanks, Scott.....that's the kind of info I need.

 

[Bondo]

Re: Do pushed out frost plugs mean cracked block ?

My question is....if the block was cracked, wouldn't there definitely be water or coolant in the oil even if it had not been run in that condition ?

Ayuh,.... You have to Assume the block is Cracked....

The core plugs aren't a viable indicator...

When it thawed, the water could easily run out the core plug holes, rather than through the Cracks...

 

[Howard Sterndrive]

Re: Do pushed out frost plugs mean cracked block ?

There was no water in the oil,

never is with a cracked block
the water is UNDER the oil
oil and water do not mix well, so the water sits on the bottom- you pull the dipstick and see only oil

If you loosen the dipstick fitting from the bottom of the oil pan, you will see the water running out the threads (unless someone already purged it)

 

[jimmoe]

Re: Do pushed out frost plugs mean cracked block ?

Here's a little more info...
the freeze happened prior to this year
it was in the water this spring but only to find out it did not shift
it has been started since and seems to run good and exhaust looks good
the mechanic did not mention oil or coolant in the bilge

I'm aware all this does not mean there is no problem.....
briefly, how does one go about doing a pressure test on the block?
(can it be done without dismantling the heads, etc?)

 

[Howard Sterndrive]

Re: Do pushed out frost plugs mean cracked block ?

briefly, how does one go about doing a pressure test on the block?
(can it be done without dismantling the heads, etc?)

it has to be done without dismantling anything

remove water feed hose to thermostat hsg (green arrow)
disconnect water hoses from exhaust manifolds
use 5/8" bolts or pieces of wooden dowel etc to block hoses at X's
put 5 or 10 psi air in at green arrow.
listen for hissing

 

[Howard Sterndrive]

Re: Do pushed out frost plugs mean cracked block ?

the mechanic did not mention oil or coolant in the bilge

coolant?
it has closed cooling?

 

[fishrdan]

Re: Do pushed out frost plugs mean cracked block ?

How much do they want for it and how much are you willing to spend? Be aware OMC has been out of business for years, so you are buying into a problem right there.

I agree with the others about the pushed core plugs, the block (and manifolds!) are to be thought of as cracked, until proven otherwise. If the block and manifolds are not cracked, but the core plug behind the flywheel is pushed out, you will need to remove the engine to get them installed again, big pain. Then there's the shifting problem, just an adjustment, bad cable or drive problems?

I think you would have to get the boat for almost nothing, to ensure you don't get taken. IE: the repair costs could be more than the boat is worth...

 

[tpenfield]

Re: Do pushed out frost plugs mean cracked block ?

Jimmoe . . .

I think you already know enough about this boat/engine to walk away. So, you should walk away.

 

[jimmoe]

Re: Do pushed out frost plugs mean cracked block ?

here's the description......

"I bought this boat last week and was told it ran great but wouldn't shift. It has a 4.3 with a omc outdrive.The boat has always been covered on the lift or in the garage so the interior is in excellent shape. No soft floor or worn out carpet in this boat. The outside has a few dings that you would expect in a 15 year old boat, but is in overall good condition. There is a little oxidation or fading in the back, but with some elbow grease and time it will come out and look like new. Now to the bad. I brought the boat to the marine to have it winterized and have the shifting problem looked at. He found the the shifting problem is minor and looks to be a simple cable adjustment. He was able to shift the boat manually so there is no outdrive or gear problems. He also found that the frost plugs on the side of the block were blown out the side from freezing at some point. With how the motor sits in the boat it is impossible to tell for sure if the block is cracked or not, but there is a chance it is. There was no water in the oil, so it is possible that it is just the frost plugs, but there is really no way to know for sure without taking it out and inspecting it. The boat is currently winterized, but I do not have the time, money or space to try to fix it or look further into the motor issue. The boat sits on a heavy duty galvanized roller trailer with 2 brand new tires. I need this thing gone ASAP, so make me an ....."

The pics looked good, boat and trailer. He was asking 900.
I ran across it looking for a trailer...it would cost me a tank of gas and who knows how much to get rid of the boat&motor...............I (shamefully) offered him $300 but suggested he try the other 2 guys that were interested. His bottom line $600.
It's too bad but ya'll are right....it could easily cost more to fix than it's worth.

It probably doesn't have closed cooling....I don't know much about other I/O's, (kind of a dummy), I was thinking it would be like my 470.

Great photo and explanation, Howard!

 

[sschefer]

Re: Do pushed out frost plugs mean cracked block ?

Don't know if this was said yet or not but I thought I'd read where the boat was recently run. If it didn't fill with water from those plugs being pushed out then they didn't go all the way and that might mean that the freeze wasn't all that bad and the block is o.k. Not very likely but it could be. It could also mean that they were replaced once before and were never set correctly, I've seen that too. Either way, you're gonna have to pull the motor to fix that so you might as well just go through it while it's out. Or.... walk away.

 

[Bridar]

Re: Do pushed out frost plugs mean cracked block ?

From your posts, there doesn't seem to be any obvious issues with the outdrive. If I were in your shoes, I would factor in the price of a longblock and decide if the overall boat is what you want (to keep, operate & maintain), and if it will be worth enough on the market should you decide to sell it later.

I agree 100% with the guys about the core plugs. Eventhough we Canadians also call 'em "frost plugs", they were never designed to protect an engine from freezing. You must assume the water jacket is cracked until proven otherwise. Unfortunately, you would need to pull the engine, replace the core plugs, and pressure test the block to find out. Not something a person normally does prior to purchasing a boat.

If you do end up buying it in the $600-900 range, and the block tests out okay, you would certainly be ahead financially. Just don't gamble on that (unlikely) possibility.