How to check if block is cracked?

scottyb

scottyb

New member
So the 4runner started overheating on the highway on my way to Denver a few weeks ago. I wasn't too far outside of Fort Collins, so I decided to limp it home while riding on the shoulder. I ran until the temp got close to the max, and then I would shut it down and let it cool for a while. It took about 2hrs to go 10 miles. In retrospect I should have had it towed, but it's past that now.

After getting it home I started to inspect. I saw the coolant overflow reservoir bubbling, white smoke out the exhaust (it smelled a little sweet, but I didn't want to huff exhaust too long trying to determine just how sweet), and the engine was drinking coolant like Gatorade. So, I determined it was the head gasket. I tore into the engine, got a gasket kit, and finally got the heads off.

I brought the heads to Napa's machine shop and they cleaned them up, but unfortunately they found they were both cracked...

IMG_0278.jpg~original


IMG_0277.jpg~original


IMG_0279.jpg~original


So now I know I need new heads, but I wanted to verify that the block isn't cracked before I go find some. Is there a good way to check besides a visual inspection (I can't see anything obvious)? What are the common failure points? I don't really want to remove the crank and pistons and bring the block to a machine shop, but if I need to that's what has to happen.

Any help is appreciated
 
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Thumbs up for smokin both heads!!! I doubt your block is cracked. Cast iron vs. aluminum. Cast almost always wins. But if you got the motor down that far unbolt the bell housing and rebuild it. If your already buying head gasket set and heads what a little more for some bearings.
 
attitudeofgratitud said:
Thumbs up for smokin both heads!!! I doubt your block is cracked. Cast iron vs. aluminum. Cast almost always wins. But if you got the motor down that far unbolt the bell housing and rebuild it. If your already buying head gasket set and heads what a little more for some bearings.
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True enough =)
 
Have the machine shop check the block for cracks as well before starting any rebuilds. At this point isn't it cheaper to buy a complete used engine?
 
IanB said:
Have the machine shop check the block for cracks as well before starting any rebuilds. At this point isn't it cheaper to buy a complete used engine?
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Well the issue is cost. It looks like I can pick up used cylinder heads for about 200 a piece, where a used engine is about 1500 on ebay. I would like to rebuild, however money is really tight and I need some transportation so i really just need to find the quickest way to make it drive-able
 
scottyb said:
Well the issue is cost. It looks like I can pick up used cylinder heads for about 200 a piece, where a used engine is about 1500 on ebay. I would like to rebuild, however money is really tight and I need some transportation so i really just need to find the quickest way to make it drive-able
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I would start calling wreckers and see what a used engine is worth. Also try looking on craigslist for local partouts and that kind of thing. Complete engines can be had for cheap if you find the right deal. Is the engine on ebay used, or remanufactured?
 
IanB said:
I would start calling wreckers and see what a used engine is worth. Also try looking on craigslist for local partouts and that kind of thing. Complete engines can be had for cheap if you find the right deal. Is the engine on ebay used, or remanufactured?
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The ebay engines are lightly used (under 60k miles). However, I did check out car-part.com, which is a database for most salvage yards, and found an engine with 140k on it for $850 nearby. Not too bad, but it's still 450 more than 2 cylinder heads... Plus if I get the cylinder heads, I can replace the head gaskets and a number of other seals. The way I see it is:

Used engine:
-no/minimal reassembly required ( I do have an engine hoist, so no problem there)
-less wear than my 180k motor

Used cylinder heads:
-cheaper (provided that the block isn't cracked)
-I have already torn the engine apart, so I can replace all the gaskets
 
scottyb said:
The ebay engines are lightly used (under 60k miles). However, I did check out car-part.com, which is a database for most salvage yards, and found an engine with 140k on it for $850 nearby. Not too bad, but it's still 450 more than 2 cylinder heads... Plus if I get the cylinder heads, I can replace the head gaskets and a number of other seals. The way I see it is:

Used engine:
-no/minimal reassembly required ( I do have an engine hoist, so no problem there)
-less wear than my 180k motor

Used cylinder heads:
-cheaper (provided that the block isn't cracked)
-I have already torn the engine apart, so I can replace all the gaskets
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I'm assuming that with 2 cracked heads and your stated concern for the integrity of the block, that you would want to have the block checked over before throwing new heads and a bunch of seals/gaskets at it? How much disassembly is required to check the block over and what cost is associated with this step(I'd ask your machine shop that question to be sure)? It might be $450 well spent to get a complete engine with lower miles, just something to think about.

Either way, good luck getting it back on the road quickly and cheaply.
 
IanB said:
I'm assuming that with 2 cracked heads and your stated concern for the integrity of the block, that you would want to have the block checked over before throwing new heads and a bunch of seals/gaskets at it? How much disassembly is required to check the block over and what cost is associated with this step(I'd ask your machine shop that question to be sure)? It might be $450 well spent to get a complete engine with lower miles, just something to think about.

Either way, good luck getting it back on the road quickly and cheaply.
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Yeah, good point. I will call around and get some quotes
 
Hey man, I just got out of the same boat and both my heads were cracked too. I have 206K on mine. Your block is probably fine, mine was and my cracks were in the same spots. If ithe block is cracked, it'll be cracked where the heads seal up so you should be able to see that pretty easily. If it's cracked on the side or something, you'd probably know about it because it would usually be leaking.

I did the full rebuild, got new (used) heads, resurfaced them and the block, and it all cost me $2,236.00 total w/ a 1 year warranty. That included all labor, even the removal and installation of the engine in my truck too. She runs like a brand new truck now!
 
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brian2sun said:
Hey man, I just got out of the same boat and both my heads were cracked too. I have 206K on mine. Your block is probably fine, mine was and my cracks were in the same spots. If ithe block is cracked, it'll be cracked where the heads seal up so you should be able to see that pretty easily. If it's cracked on the side or something, you'd probably know about it because it would usually be leaking.

I did the full rebuild, got new (used) heads, resurfaced them and the block, and it all cost me $2,236.00 total w/ a 1 year warranty. That included all labor, even the removal and installation of the engine in my truck too. She runs like a brand new truck now!
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Yeah it sucks a little, but I tend to be an optimist so I like to see it as an opportunity to learn about the motor=).

I am also starting to agree that the block probably isn't cracked. I can't see any cracks after a close inspection of the mating surface on the block, there is no coolant in my oil, and there is no leaking on the outside so I think I should be good.

After calling a machine shop it is only $100 to get the block magnafluxed, however to do that I have to remove the internals. And if I remove the internals, it was recommended to me to replace the rod bearings, crankshaft bearings, piston rings, etc (rebuild).

So as it stands:

1) The preferred route: Remove the internals, magnaflux the block, rebuild the engine: ~$2,236.00 (brian's cost)

2) Low risk: Used engine: ~$850 + $340(warranty) ~$1190

3) Riskier route, but cheaper: Get used heads, install the gasket kit I bought: ~$450

Because of budget I'm going ahead with option 3. I would love to rebuild but I'm not quite out of college yet so there are no extra funds for that. There is a risk of a cracked block, but I'm willing to take the chance. Thanks for the help reasoning through this one
 
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