Cylinder Scar Armchair Technicians speculate

[19963.4lsr5]

For those not following along in my repair thread.......what I thought was a bad head gasket is far worse.

This engine came out of our 96 after it got totaled after being T-Boned on the drivers front wheel. It had 230,000 miles on it at the time of the accident.

I ran the engine periodically over the next 2 years until I found something to put it in. I can't see what looks like corrosion happening after the accident.

Zoom in on the scar and tell me what you think. This engine ran great in both 4Runners until the antifreeze started leaking through the cylinder wall.

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[LittleCaesar]

Did something break off in that cylinder? Ouch. Did you ever perform a compression/leak down test on it before the HG leak?

Just another testament to how good Japanese engineering can be.

 

[19963.4lsr5]

It never had any indication there was something wrong until the water vapor at cold startup. So I never thought to do any testing.

I can't see the impact of the accident transferring the ring scars to the cylinder. It looks like it was rust.



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[Desertwind16v]

Wow that is some deep pitting. At this point it doesn't matter what caused it, the block is probably junk. It looks so deep that getting it bored out might not even be possible let alone worth the cost.

 

[sleepydad]

For those not following along in my repair thread.......what I thought was a bad head gasket is far worse.

This engine came out of our 96 after it got totaled after being T-Boned on the drivers front wheel. It had 230,000 miles on it at the time of the accident.

I ran the engine periodically over the next 2 years until I found something to put it in. I can't see what looks like corrosion happening after the accident.

Zoom in on the scar and tell me what you think. This engine ran great in both 4Runners until the antifreeze started leaking through the cylinder wall.

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That is what it looks like when you run something in your cylinder.

http://www.toyota-4runner.org/3rd-gen-t4rs/256595-p03050-cylinder-5-misfire.html#post2990537

To me it looks like somebody tried to do a JB weld fix that cylinder. After some time with the grinder.

 

[Gary Blake]

Well my armchair view would say it was probably a void in the original casting that became exposed when the engine developed and little bit of normal wear on the cylinder wall. Just going by the depth and horizontal band the scar seems to be following

Can't see it being corrosion in an area that is continually bathed in oil and wiped down by the piston rings. Don't see any signs of corrosion in the deepest parts unless you cleaned it all out. Looks more like a rough casting edge.

Just guessing though, probably worth a whole 2 cents. Maybe someone with metal casting experience can chime in.

Gary

 

[19963.4lsr5]

Wow that is some deep pitting. At this point it doesn't matter what caused it, the block is probably junk. It looks so deep that getting it bored out might not even be possible let alone worth the cost.

I'm certain that's the source of my coolant leak.


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[96RedRunner]

Elbow on workbench thoughts. What your water jackets look like rust wise?
Looks as the water jacket side of cylinder rusted through to piston side.
The piston stroking kept polishing the edge of corrosion, as it got worse the combustion heat caused the pitting? make any sense?

 

[19963.4lsr5]

It could have been corrosion. And eroded from the water jacket into the cylinder wall. I just feel it didn't happen after the accident. And with the miles on it when we bought it I didn't think it sat long. It was driven until the suspension and current tires were shot and then dumped. I don't remember the coolant looking horrible but it got all fluids changed.


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[audiness]

Well my armchair view would say it was probably a void in the original casting that became exposed when the engine developed and little bit of normal wear on the cylinder wall. Just going by the depth and horizontal band the scar seems to be following

Can't see it being corrosion in an area that is continually bathed in oil and wiped down by the piston rings. Don't see any signs of corrosion in the deepest parts unless you cleaned it all out. Looks more like a rough casting edge.

Just guessing though, probably worth a whole 2 cents. Maybe someone with metal casting experience can chime in.

Gary

I agree with this diagnosis

 

[19963.4lsr5]

I'm pretty sure it could be resleaved to repair the block.




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[19963.4lsr5]

This is the rear cylinder on drivers side. It's very evident with a finger nail.

What the heck happened to this engine in the past. I need to see if this block has a serial number and see if it's from another vehicle.


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