Technical Is my block junk? Freeze crack.....

Pulled my avatar coupe out of winter storage the other day and noticed a small puddle of coolant under the engine. Figured it was a minor leak somewhere. After some looking, found a 3 inch crack in the side of the block about a 1/2" below the deck.
Looks like a freeze crack? It was in an unheated building and the coolant tested to -20. It did get that cold here over winter...
Anyway, I was wondering how bad this is. No coolant in the oil, and it just weeps a bit after the engine cools. While at running temp it expands enough to seal it up.
Will this crack keep expanding? Does it weaken the deck surface? Stop leak and run it? Replace block?

 

Forgot to add, the engine is a small block Chevy if it matters.

 

It could be repaired.... You might have to pull the motor out and disassemble it....

 

If it's a 350, your better off replacing the block...

 

I would peen it with a ballpeen hammer from both top and bottom. Them run some block sealer in the antifreeze. You can also coat the outside with some good epoxy.

 

I have welded cast iron successfully in the past. Preheat and nickel rod. I have also failed miserably. Welding cast iron can be a tricky thing. That being said, I would never even attempt that repair. It might could be done, but WHY? There are at least a couple million sbc blocks out there with no cracks. If that were mine I would clean off that area real well, slap some JB Weld on it and drive the shit out of it while I was looking for or building a replacement.

 

If you were a machine shop owner from Sulphur Springs TX and you had a cracked block in your shop truck you would have invented and used this:

How It All Began: A Mom and Pop Operation
The J-B Weld Company was founded in 1969 by Sam and Mary Bonham. Sam had discovered a need for a “cold weld” product to use in his truck service garage, instead of traditional torch welding. Working with a Texas A&M chemist, he formulated an original “tougher than steel” two-part epoxy and named it J-B Weld. Sam and Mary soon went from selling the product out of their car to auto parts jobbers across Texas, to selling it in stores throughout the U.S. and internationally.

When I was a kid in the early 70's, I helped my grandfather pull an old Farmall tractor he used in the 40s and 50s from the old tractor shed, it had a crack in the block. He drilled a hole on either end of the crack, ground a V in the crack and cleaned it really well. He laid a bead of JB weld in the groove and then "textured" it with a rag or something, and unless you knew where the crack was, you would never have seen it. It didn't leak.

 

I had that happen a few years ago on a 327. Mine cracked so bad it pushed the casting out. I looked into fixes because I also did not have water in the oil. I found a welding rod called muggy weld. Ended up dropping a 350 crate motor in and the 327 sits in the corner waiting to be fixed some day.

 

There's also the ol' school way of repairing the block... The old pipe plug trick....
Maybe someone else here can explain it better than me....

 

Devcon-Metal epoxy or JB Weld....gotta v-groove it, drill tiny holes on each end, clean and prep area very well. Clean and dry is important. Fill with product, use small tool to trowel or smooth, forcing it into the crack/holes. Should be good for awhile. This can also be TIG braised with bronze rod...but block may have to come out if not accessable easily

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Here is an interesting way
Google repairing a freeze crack in a block and several ways come up
Welding, brazing, pinning, resins, additives to coolants

 

I get a newer 350 with a roller cam set up and make the swap worth while..

 

It can probably be fixed, but is it cost effective is the answer. A rare or hard to get block would get more attention on trying to fix it, where a more common SBC would be replaced. I had a 350 do that once, I junked it and bought another block cheaper that trying to fix it.

 

common spot for SBC to freeze crack-too thin there to fix by drilling and tapping over-lapping plugs.welding sometimes works ,but tends to chase the crack along.I'd clean it as well as possible and JB weld it-your'e not out much if it doesn't work!As far as any real repair,I agree its cheeper to replace the block

 

Look at it this way... It’s broke. No matter what you try, you can’t make it worse. I would drain it, drill the ends of the crack, rough up the block, and epoxy/ jb weld it. If it doesn’t work, you’re no worse off than you are now. If it works, you’re a hero.

 

I have a friend who years ago had a casting defect on the side of his Detroit diesel, it was in the water jacket. He took it back to the dealer and they drilled the the spot out threaded the hole and JB welded in a 1 1/2" pipe plug. Held for a million miles.
Todd

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It's a common as dirt SBC block, why waste the time and money trying to fix it so it can let you down in the middle of nowhere. Those blocks are too easy to find to spend the time and effort to save it. take it as a sign it's time to refresh the engine and go on with life.
SPark

 

Drill a hole on each end of the crack,and MIG braze it.

 

Thanks, I'm pretty sure I can seal up the leak. Was more concerned if the crack will keep "running" or if any other issues would happen from having a crack there.
I hate to tear this engine down as it runs great with no other issues. Probably less than 30k miles on it.

 

Can you get to it ti drill each end? Then drill and tap each end and do like the video above. You could even do the drill and tap stitch method. That is a good repair. If you have to pull it to do that I might just change the motor. If it has some expensive machine work I might pull it and stitch it, but if it is a stock motor I would probably replace it.
The glass type block sealers seam to work ok. That should get you the season out of it before you change it. Lots of options. Do you feel lucky?

 

Common area for a freeze crack to occur; also in the valley area, so you might want to check that out also (milkshake oil?). If it's just the outer, then "stitching" it works good, if done by someone with experience (try a diesel repair facility-those engines can cost $$$$$). If it's in the valley also, find another block. I am Butch/56sedandelivery.

 

Don't dick around with any of these half assed solutions. Stitch it up

 

>>>No coolant in the oil, and it just weeps a bit after the engine cools. While at running temp it expands enough to seal it up.>>>

I dunno? Before concluding it's a real 'crack', you might want to try wiping the whole wet-looking area above and below the deck with a dry cloth when its weeping.. Then hold a dry cloth just above the crack and watch if the crack still weeps. The crack might only be a surface imperfection that effectively wicks coolant coming from above. Even if the temp got well below -20*F, I think the coolant would only turn to slush and not freeze solid enough to crack blocks or burst pipes. Jack E/NJ

 

cheaper to replace the block its just a SBC

 

We need to know if it's a 350... Roller maybe or a early '70s 2er4 bolt block.... What's the casting number in back of the block and the vin number??????......

 

The stitch method is a great thing for an expensive or hard to get block or other casting of some sort.....but way too much work for a small block....epoxy or weld and move on....ifnit starts leaking again, then you know the answer

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If not sure if n its cracked, pressure check the system and see where its leaking....cud very well be coming from the head gasket....

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Since it seems to be seeping very little, you have several options.
1- Run it for awhile and see if it seals itself up with some silver seal in the cooling system.
2- Stitch it. About a 2 to 3 hour job. Can be done without tearing the engine down. Rather expensive whether you do
it yourself or have it done.
3- Have it welded by a qualified shop. Finding one of those is not too easy. Here is a pic of a weld on a flathead Ford block where the frozen piece fell clear out. This was a one hour weld job with the engine still assembled.

 

It's definitely a crack. The block is a 4 bolt main 350 from a '75 truck IIRC......nothing real special. Bored .030 with flat tops.
I'm not gonna try to weld or stitch it. Probably just add some stop leak and keep an eye on it over the summer. Look for another block in the meantime as suggested above...

 

You need to replace with a Corvette engine this time!