Water in Cylinders, Blown Head Gasket

[hanleyclifford]

An axe, eh - do you have any Viking relatives?

[lat 64]

Granpa was a swede. Came over in '06.
Does that count?
I did notice that no one disputes my "measurement" when I have a framing axe in my hand. Maybe I should show my sensitive Side for a change?

Russ the red

[edwardc]

Causes of a cracked block

I'm curious as to the likely ways in which a block cracks. i have a particular theory in my case, but I'd like to hear what others think or know.

I can only think of three ways:

1. Severe localized overheating (clogged passage?)
2. Freeze damage
3. Mechanical impact (say, with a framing axe )

Any others? And which, if any, of these are unlikely or impossible?

Questions, questions!

[ArtJ]

Not an expert, but maybe a thrown rod would crack or break a block?

Regards

Art

[ndutton]

I once had a piston wall fail where the wrist pin attached, essentially a thrown rod. The destruction of the block was massive, looked like someone dropped a hand grenade in there.

I like the extreme temperature theory, either heat or cold and I'm leaning more toward cold.

[edwardc]

I like the extreme temperature theory, either heat or cold and I'm leaning more toward cold.

That was my original thought too, as I've found other evidence that the engine was not properly winterized in the winter of '08-'09. It looks like the P.O. didn't remove the thermostat before circulating antifreeze thru the engine. This would cause the antifreeze to bypass the head & block, allowing them to freeze. And I did find cracks in the old head and the thermostat housing ears. My working theory was that there were also small cracks in the block that went unnoticed until they opened up wide.

But now I'm not so sure. How succeptable is the block to freeze damage? Won't the freeze plugs pop out first? (they didn't)

I'm beginning to lean towards the theory that some local obstruction in the block's cooling passages caused the region around the #3 exhaust valve to be starved of coolant, causing it to overheat and crack.

But I don't know the layout of the cooling passages in the block. Is this kind of blockage even possible? Maybe Don could weigh-in here.

[ndutton]

But now I'm not so sure. How succeptable is the block to freeze damage? Won't the freeze plugs pop out first? (they didn't)

OK, the following is something I learned long ago from an engine builder under exclusive contract to Mercury Marine Division. I didn't confirm it independently so take it for what it's worth.

What are commonly called freeze plugs are actually core plugs, necessary in the block casting process to align and evacuate the internal sand form. While it's true the closing plugs may pop under freezing conditions, that's not their primary purpose and not a guaranty. The core plugs may be strategically located to take advantage of this side benefit however.

Anyway, that's my story and I'm stickin' to it.

[keelcooler]

Niel’s Merc mechanic friend is correct. The old auto and marine engines of the 50’s and 60’ were heavy walled and could withstand freeze expansion trauma dropping the plugs into the bilge. On those old set ups only the manifolds and oil coolers would blow. For the last 20 years Merc has only used GM engines. The 350 cracks on the outside and the 454 likes to crack on the inside push rod alley areas. The small GM 4cyl will some times survive a mushy salt water freeze. The v6 cracks inside and outside. A cooling jacket full of sand or sediment will sometimes not allow proper circulation of antifreeze causing isolated freeze damage.

Our motors tend to collect block sediment on the hot port side away from flow blast at the side plate inlet. That’s why Don has recommended the addition of a rear downward flow hole in the side plate fitting in an effort to direct some flow around the rear cylinder to combat this build up.

Many an a4 block has frozen and lived to run another day. Not so much for our manifolds and heads.