4.3 - Is this what a cracked block looks like?

[ShoalSurvivor]

Kind sirs,
My bilge pump fired up yesterday. I was quite surprised? and it kept firing. about 1/hour? 1-2 gallons of water.
Upon first inspection, I found a poor seal and probably bad valve on a water line. This didn?t seem to be enough?
Upon further inspection, found significant corrosion an evidence of water dripping from the starboard side, forward portal of the engine block (right under the engine mount). Doesn?t look like anything serviceable in there? and my guess is that it?s really bad.


Engine is a 2004 4.3 Alpha I Gen II. The original was also a 4.3, but replaced 2-3 years ago with a Repower 4bbl 4.3 engine.
drive SN: 0L102679 1.63R is stamped in, but 1.81R is hand written next to it.
Engine S/N: 90004747


Many thanks in advance for your assistance!
Michael

 

[bruceb58]

Looks like the block drain might be leaking. Hard to tell from pics if there is a crack.

If it's really dumping that much water, should be easy to find and take a pic of it.

Do you have freezing temps in your part of the country?
If so, did you drain the block during he winter?
Have you been running this summer and this just happened?

 

[ShoalSurvivor]

The riser drain plug is most definitely leaking, but that's not the source. The pinhole in the valve could be the source.
Certainly, i will replace the plug and re-check for leak, but, my real question is:

Is the corrosion in the "portal" behind the engine mount a typical indicator of a bad block?

There are four of these portals, 3 are clear, the one near the bad valve is corroded. I cannot feel inside because it's blocked by the engine mount. It's possible that the corrosion just happens to be where the water wound up, and may have been sprayed there, but when the engine is running, it looks like water is pouring out of the corroded looking "portal".

In Southern California... what does freezing temps mean?

 

[bruceb58]

Where in So Cal? That's where I am. Unless you are in the mountains, you very likely do NOT have a cracked block.

 

[poconojoe]

Your first picture just looks like the drain fitting needs to be sealed and tightened. Or it might just be ok. The second looks like the block plug needs to be replaced. That looks like where the leak may be. That plug seems to be badly dislodged. (some people call them freeze plugs).

 

[Rick Stephens]

Yup, go get yourself some brass core plugs and replace them. Beats a cracked block any day :^)

 

[Fun Times]

In Southern California... what does freezing temps mean?

That's the days when you have to put on a lite sweater and debate wearing pants vs longer shorts.

Joking aside, it's still a good idea to drain the water out of the engine block, exhaust manifolds and any oil coolers if probable just to be on the safe side November - February as you never know what could happen. It's cheaper insurance.

Have you tried running the engine and looked for water flowing/dripping.

 

[bruceb58]

Out of curiosity, were the core plugs in this new engine brass or steel?

 

[ShoalSurvivor]

I live coastal San Diego. We boat year round.

I don't know the material of the core plugs.

I have run it and the water appears to run out of the "portal" (or whatever the round pocket behind the mount is called). There is corrosive build up there too. Could be the core plug. I'll check that out.

I will replace rhe

 

[Bondo]

I have run it and the water appears to run out of the "portal" (or whatever the round pocket behind the mount is called). There is corrosive build up there too. Could be the core plug. I'll check that out.

Ayuh,..... What you are callin' "Portals" are the holes used to remove the sand used in the castin' process of the block,.....

The little round chunks are Core Plugs, 'n automotive are steel, where as marine core plugs are brass,....

Core plugs are a resistance fit in their bores, 'n are driven into place,....

If you lift the motor atad, remove the motor mount, 'n install a new brass core plug,...
You'll need to realign the motor/ drive with an alignment bar to finish the job,....

 

[ShoalSurvivor]

That's better news than I expected. Thanks for explaining the brass plug.

i service the lower unit but have not done an alignment myself. I do most repairs myself. Do I need a hoist? I'll read up on alignments.

 

[Bondo]

Do I need a hoist?

Ayuh,.... Ya need a way to support the weight of the motor on the corner yer removin' the motor mount from to replace the core plug,...
Donno yer boat, so can't say how you oughta be doin' it,....
A big ole 2x across the gunwales might work for ya,... donno,...

I'd do 'em All, as ya know the rest are gonna rust out,.....

For the alignment, the motor rests on it's mounts, as you adjust 'em, with a wrench,....

Btw,.... Donno when it'll happen, but there's 2 more core plugs, behind the flywheel,....
The motor will have to come out to change 'em,....

 

[ShoalSurvivor]

They were steel, not brass. So... they've been replaced! Now 1% of my boat should be good for a few years

 

[Rick Stephens]

Don't forget that there are two core plugs on the front of the engine and two more on the back under the fly wheel.

 

[biggjimm]

Yeah, looks like steel plugs & as Bondo & Rick pointed out, there are a few more that are a little harder to get to, as in you have to pull the motor & remove the flywheel, that being said, you know how many guys find water pouring out of their block & think "it's probably just a core plug" only to actually find a big ol' crack in it. The answer is almost all of them. Ha. Changing a few core plugs beats a cracked block any day, huh?