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Freeze Damage

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bdf

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Looking for help on assessing freeze damage. Live in NC where we have broken historical records for low temps and extended days below freezing - not a good year to skip winterizing. Tried to take precautions with heat in the engine compartment but underestimated the cold. I anticipate some ostracizing and deserve it but hope to move beyond that and determine how much damage exists.

I have observed at least one freeze plug is blown but do not know how many there are and where they are. Does anyone have a diagram to help locate the plugs or general advice on how to assess the overall damage? Guessing I'll need to replace the blown plugs (assuming I can get to them) and then start it up to look for leaks.

Appreciate any advice (and well wishes),
bdf
 
Ayuh,.... Can't tell ya where the core plugs are, unless ya tell Us what motor ya got,....
 
bondo said:
Ayuh,.... Can't tell ya where the core plugs are, unless ya tell Us what motor ya got,....
Click to expand...

Details, details....so this isn't the clairvoyant marine engine forum?....my bad....

Engine:
Mercruiser MCM 4.3l / Family 6M9XM04.32VC / D.O.M. Feb 2006

I gather there might be 6 freeze plugs with at least two behind engine mounts that would require engine removal to replace. Are all 6 freeze plugs visible for inspection? To determine if a plug needs to be replaced, do I simply look to see if it is flush with the motor (one completely popped and sits in the bottom of the engine compartment)?

My initial thought was to wait for a warming trend, visually inspect the freeze plugs and replace as needed, fire it up and look for leaks. Unless of course the engine needs to be pulled to replace a plug(s).

Thanks in advance for your insights,
bdf
 
"Freeze" plugs often do not get pushed out from frozen engine blocks cz that's not really what they are there for. They are there to help get the sand out of the casting at the foundry. The correct term is "core plug". Just so you know. OK now let's hope that the water jacket of the engine did not crack.
You really should remove the engine to get at the core plugs. There are a couple on the rear of the engine hiding behind the flywheel. If you want peace of mind on the water (who doesn't) you'll want to inspect those. If one just fell out, that's probably not good as it would mean the hole it is pressed into has opened up somehow.
You won't really know anything until the engine has thawed out of course, but the worst case scenario is that you will be buying a new (remanufactured) short block and switching over the existing components from the dead lump. A chevy 350 short block is about 1500-2000 if that helps at all. Good luck!
 
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bdf said:
Engine:
Mercruiser MCM 4.3l / Family 6M9XM04.32VC / D.O.M. Feb 2006

I gather there might be 6 freeze plugs with at least two behind engine mounts that would require engine removal to replace. Are all 6 freeze plugs visible for inspection? To determine if a plug needs to be replaced, do I simply look to see if it is flush with the motor (one completely popped and sits in the bottom of the engine compartment)?

These are NOT freeze plugs..... they are casting core plugs (aka Welch plugs) that have become necessary for the casting process.

If a cold and long enough freeze caused one or more casting core plugs to be pushed out or their bores, and if no damage occurred to the cast iron, you are very lucky!


My initial thought was to wait for a warming trend, visually inspect the freeze plugs and replace as needed, fire it up and look for leaks. Unless of course the engine needs to be pulled to replace a plug(s).

You could insert the rubber/expandable type plugs for a test.
Click to expand...
 
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Thanks for the quick reply. I am not holding out much hope that the block is not damaged. Do you have a rough estimate on the cost (labor and additional parts) beyond the cost of the short block? I'm guessing the cost of the block is the easy part.....
 
depending on the winterizing procedure and if its only the block then about 2K for a long block, possably new manifolds and risers.
average parts swap time with install 10-15 hours
 
bdf said:
Thanks for the quick reply. I am not holding out much hope that the block is not damaged. Do you have a rough estimate on the cost (labor and additional parts) beyond the cost of the short block? I'm guessing the cost of the block is the easy part.....
Click to expand...

Suggestion:
First learn the extent of the damage.... if any. Most Marine engines that have suffered from freeze damage will still start up.

Once you have this info, you can move forward.


.
 
Just because the "freeze out" plug popped, does not mean you don't also have a cracked/warped head(s) and cracked manifold or elbows. Oil cooler , if equipped not immune to damage.
 
[h=3] [/h] Freeze protection is not the original purpose of the casting core plug (aka welch plug).
These plugs are simply used to close off the open ports in the casting. The ports were formed by supporting arms of the sand "core" which was used to form the hollow jackets within the interior of the cylinder block casting while molten iron was being introduced.
Thus the proper term is "core plug" or "casting core plug"!

The occasional freeze that DOES push the casting core plug out that also just happens to prevent cast iron freeze damage, is simply a random occurrence.......... and a lucky one at that.

However, for some of the more expensive engines, these ports are threaded, therefor the core plug is also threaded. These do not push out easily from an H2O freeze .... of which should be Ethylene Glycol, NOT water!

While the early engine castings did use casting core ports (that were closed off after the casting process), I'll suggest that the term "freeze plug" originated way back when automobile owners routinely used H2O for coolant (in lieu of today's Ethylene Glycol mix or equivalent).
During a freeze, the core plugs would be pushed out, randomly saving the cast iron cylinder block.

In a misnomer fashion, average Joe began referring to these as "freeze plugs".



.

 
Sorry to hear of your freeze issue. I would do the temporary rubber plug for those that came out to test as suggested.
I don't know that it's necessary but I drain the intake manifold and all hoses along with the block on my 4.3 VP for layup.
Curious, is/was your boat still on the water.
 
daves69 said:
Sorry to hear of your freeze issue. I would do the temporary rubber plug for those that came out to test as suggested.
I don't know that it's necessary but I drain the intake manifold and all hoses along with the block on my 4.3 VP for layup.
Curious, is/was your boat still on the water.
Click to expand...

We have a temporary reprieve in cold weather so I hope to get out and inspect the engine today. As noted above, I am not holding out much hope. I'll see if I can find some of the temporary plugs locally. Are these typically available at a local auto parts store? The boat is not in the water - it is next to my house which added to my false sense of security that I could monitor the temp of the engine compartment.

LifeIs(still)Good
 
OK, replaced the casting plugs and started it up only to find that there are cracks in on. both sides. If my ignorance is not already apparent, it will be now. What are the units on either side of the engine called that the water circulates through? Those are both cracked. Are this part of the core block or can they be replaced separate form the block?

bdf

tried to upload an image but failed to upload (no error message)...is there a size limitation?
 
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well then minimally I have two cracked exhaust manifolds.....and at least two plugs that will need replacing (2 of the four I found were popped)...think it is time to start looking for a reputable mechanic....
 
In years past I've repaired some freeze damage on 4 cyl. GM blocks and manifolds. It might work for you if you don't run the boat very hard. I'd put in the plugs, and start it up. If no water gets in the oil, the block may be fine. The manifolds don't have much pressure on/in them. If the cracks just dribble, clean the cracked area real well and JB weld them. I've JB welded a 8-9 inch crack through the water jacket on two 4 cyls, and a couple of exhaust manigolds. It'll last 3-4 years before ya need to change it. If you're sking or running at high rpms much- I wouldn't take that approach.
 
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