Froze the block--what to check now?

[cheburashka]

This is in reference to a Mercruiser 140, early '70s vintage.

I'm new to this, and I'm learning. Learned a big one today. I thought I had drained the water from the entire system by pulling the water hoses on the outdrive, but it appears that I didn't drain the block. We had a two month hard freeze here. When I started the engine today there was water everywhere. Preliminary examination shows two freeze plugs on the port side of the block are completely out of their holes. I've replaced these (they're accessible with the motor installed) and got it running again, but discovered that I had a broken flange on the lower thermostat housing. I've ordered new parts for the thermostat housing--it had been welded once in the exact same place and I'm thinking maybe the engine had been through a hard freeze before. I've checked, and the oil is still transparent, so I don't think there are any internal problems, but I haven't run it enough to really know.

Main question--is there any chance at all that it can be saved? Secondary questions-- Are there other water passages that could have cracked? I know the freeze plugs aren't intended to be a cure-all for fools like me who don't drain their blocks, but is it possible that the freeze plugs and the t-stat housing took up all the force of the freeze leaving me with a block that's still usable? Third question--are there other freeze plugs that I should know about that have probably blown? Fourth question--how can I be sure that I've solved all of the leak problems (assuming it can be done with the engine in the boat) before I put it back in the water? I've heard you can use compressed air, but I wouldn't know how to pressurize the system.

Thanks for any help you can give me. And yes, I know it was a stupid thing to do. Rest assured, you can say nothing that will match the cold glare I get from my wife, who asked me to have the marina winterize the boat.

 

[HT32BSX115]

Re: Froze the block--what to check now?

I would say that you have destroyed the engine by not draining it. And when you drain it you MUST remove the drain valves poke a piece of wire into the holes to get the small pieces of rust out that can prevent you from draining out all the water.

You could replace the soft (they're NOT freeze plugs!!) plugs and plug up all the holes and see if you have any leaks by pressuring up the block with compressed air. BUT if you cracked the thermostat housing with ICE you can BET that there are cracks in the rest of the block.

I would start looking for a long block or another engine.



Sorry my friend....it's a hard lesson to learn but it's VERY common....welcome to the club!



Regards,


Rick

 

[Manipulator]

Re: Froze the block--what to check now?

check to see if you have power steering cooler and an engine oil cooler. They tend to crack fairly easily. We found both to be cracked on my dads boat this year. They still had water in them. Doh!

 

[cheburashka]

Re: Froze the block--what to check now?

Thanks for the quick response.

No, there's no power steering or oil cooler. It's a pretty simple old engine. I'm going to gamble a bit and replace the parts I know to be broken, just in case. I'm hoping that if there are cracks, they're external and can be fixed with a good metal-filled epoxy. I'm a bit concerned at this point because the engine isn't idling well, which could mean that water is getting into the cylinders. I guess now it's just a matter of waiting until the new parts arrive so I can see if there are additional cracks.

I may be able to fabricate a plate to cover and seal the thermostat housing. If I do that, covering the entire hole that it was fitted to, will I be able to pressurize the block? Is the thermostat housing the only entrance/exit for the water jacket?

 

[Bondo]

Re: Froze the block--what to check now?

I may be able to fabricate a plate to cover and seal the thermostat housing. If I do that, covering the entire hole that it was fitted to, will I be able to pressurize the block? Is the thermostat housing the only entrance/exit for the water jacket?

You'll need to Block the T-stat,.... The Water Circulating Pump,+ the Exhaust Manifold to Pressure Test the Block........

Main question--is there any chance at all that it can be saved?

Ayuh,..... Miracles sometimes Do happen....... If your Issues Are all External.....

Are there other water passages that could have cracked?

Oh Yea,......Many.......

Third question--are there other freeze plugs that I should know about that have probably blown?

Ayuh,....... There's a couple Behind the Flywheel.........

--how can I be sure that I've solved all of the leak problems (assuming it can be done with the engine in the boat) before I put it back in the water? I've heard you can use compressed air, but I wouldn't know how to pressurize the system.

Either Run it on the Hose,..... Or a Pressure Test are your Options.....

 

[cheburashka]

Re: Froze the block--what to check now?

OK. So it looks like the outdrive has to come off so I can check the freeze plugs behind the flywheel. Probably a good idea to pull it anyway. I've only had the boat for a year and I've never removed it, so it could probably use an inspection.

Could you explain more about why the exhaust manifold needs to be blocked off? Do I have to pull it, or can it be blocked at the outlet? I can see why the water circulating pump outlet needs to be blocked, but if the entire thermostat junction is sealed up at the block, isn't the exhaust manifold then out of the water jacket circuit?



Thanks

You'll need to Block the T-stat,.... The Water Circulating Pump,+ the Exhaust Manifold to Pressure Test the Block........


Ayuh,..... Miracles sometimes Do happen....... If your Issues Are all External.....


Oh Yea,......Many.......


Ayuh,....... There's a couple Behind the Flywheel.........


Either Run it on the Hose,..... Or a Pressure Test are your Options.....

 

[Bondo]

Re: Froze the block--what to check now?

To check the Coreplugs in the Back of the motor,......
It'll have to be Pulled,.... Along with the Flywheel,+ it's Cover.......
I'd just Run it,+ Look for the Leaks 1st........
But,.... Pulling the Drive,+ having a Look See is still probably a Good Idea.......

Could you explain more about why the exhaust manifold needs to be blocked off? Do I have to pull it, or can it be blocked at the outlet? I can see why the water circulating pump outlet needs to be blocked, but if the entire thermostat junction is sealed up at the block, isn't the exhaust manifold then out of the water jacket circuit?

The Manifolds can be isolated by Clamping the Hose Shut,.....That's the Inlet...
You Can't block off the water dump ports in the Riser.......This is the Outlet....

The Water Circulating Pump mounts Directly Onto/ Into the Cooling Jacket,......
You've got to isolate it Somewhere....... Capping the Hose Ports will work.......

 

[Don S]

Re: Froze the block--what to check now?

Might want to read this about Freeze Plugs

 

[cheburashka]

Re: Froze the block--what to check now?

I guess my terminology is imprecise. I'll start calling them welch plugs. For the record, I never expected them to protect the block from cracking in a freeze. I just messed up.

Bond-o, when you say "it'll have to be pulled" do you mean the entire block, or just the outdrive? Can you pull the flywheel with the engine still installed on its mounts?

 

[Don S]

Re: Froze the block--what to check now?

You will have to pull the engine out of the boat, remove the flywheel cover (which is the rear engine mounts) then you can remove the flywheel.

 

[whywhyzed]

Re: Froze the block--what to check now?

please post back if the block is cracked internal or not too - i am curious. I had a welded 3.0 in an old boat I bought (never noticed till i took the manifold off years later) it never got water in the oil - it had a big weld too so it musta froze good.

 

[cheburashka]

Re: Froze the block--what to check now?

Hey KJDKJD,

I've pressure tested the block, and there doesn't seem to be any internal damage. There is an external crack in the head, so I'll need to replace it. I've got my fingers crossed, but I think I may have avoided cracking the block. If not, I'll have a new head and thermostat housing assembly for sale on ebay.