Cracked block 6.9 IDI

[Gonzo5927]

Hey guys…. Super bummed. Was doing a coolant flush on my new to me 6.9 IDI (1986 F-250) and I guess removing all the sludge and rust in there opened up an old crack. I noticed a drip and crawled under it on the passenger side behind the starter and there’s an old rusty spot which I noticed when I bought the truck but it’s got a small coolant leak coming from it now and a crack is visible from the coolant beading (about 1.5-2”). Not sure where to go from here maybe clean it up and slap some JB weld on it until I can pull the engine at a much later date? I’ll post pictures when I get home tonight. Wasn’t thinking about it at the time.

Any advice would be much appreciated.

 

[FrozenMerc]

From your description, that is probably quite repairable. Pull the motor, tear it down, pin and braze the crack, and reassemble. Or build the motor you always wanted while you have it out, provided time and funds allow.

 

[Gonzo5927]

Thanks @FrozenMerc that’s really good news.

I already planned to pull the engine to replace leaky seals eventually when I have the time and space… and yes maybe a few small upgrades I’ve found from sleuthing the IDI forums.

Do you think I should drill the edges of crack for the temporary JB weld fix? Which JV product do you think would be coolant safe.

On the braise and pin. Not a problem, I’ve never braised before but I’m sure I can figure it out. Which pins have you seen used with success? I’ve heard Lock-N-Stitch recommended before

 

[FrozenMerc]

I hate JB weld, so I have no recommendation there. Getting it out, cleaned up, and properly inspected should be your first step. Once you know exactly what is going on, the repair path will probably present itself. Lock-N-Stich makes a very good product, but it may not be required depending on the location and geometry of the crack.

 

[hacked89]

I like JB weld if you want to hack things it works. I had a GM engine with cracked heads and I jb welded the heads to the block and daily drove it no issues.

Merc covered the right way to do things.

 

[Gonzo5927]

Merc, when you say the pins might not be necessary so you mean braiding alone might be acceptable? How does one determine what will be required?

I know I need to get the engine out and inspected. I didn’t expect to need to do this so early though. I still need to devise how I’ll be hoisting a 900 lb engine vertically out of the engine bay.

This is a learning project for me. I’m new(ish) to all of this.

 

[franklin2]

If you want to drive it and then work on it later, put some stop leak in it. I have had good luck with the Prestone Super Sealer.

https://www.pepboys.com/prestone-radiator-stop-leak/product/1137983

I have tried others, some of them are too aggressive and stop other things up. But the Super Sealer if it can work, stops the leak without clogging up everything else. When you drain the coolant later on, you will notice a jelly looking blob in the coolant, that is it.

 

[Jesus Freak]

I like JB weld if you want to hack things it works. I had a GM engine with cracked heads and I jb welded the heads to the block and daily drove it no issues.

Merc covered the right way to do things.

If it's just some common junk and you gotta keep it rolling, that's what's up. I'd blue devil a 4.6 or 5.4 and run it till it dies. But our 6.9/7.3s require more dignity! I'd love be able to say to some unknowagable person, "my engine block is brazed". "BRAZED" doesn't that just sound classy?

 

[XOLATEM]

On the jb weld thing....I rarely use it unless there is no other option..

I think I already told the story about fixing a broke starter motor with it on a weekend...the whole end cap was shattered...

I don't know if I told y'all about fixing a chrysler valve body with jb in an area that had a factory defect...someone did not set up a milling machine right and opened up a hydraulic leak...I have no idea how the thing ever made it as long as it did...unless the first owner just did not realize that the unit would not shift into 3rd....

I hope to never find any block cracks...but you never know...

Sorry to hear about it...good luck on getting it straight...

 

[XOLATEM]

"my engine block is brazed". "BRAZED" doesn't that just sound classy?

if you add 'furnace' brazed...you are now hitting a line drive past the outfielder...

Jesus Freak
But our 6.9/7.3s require more dignity!

Amen, Brother...!!

 

[Jesus Freak]

It's neat to see what some old timers did to patch the blocks on old farm tractors too.

 

[Rdnck84_03]

I can tell you that I tried the JB weld repair on a 7.3 powerstroke block that was cracked just above the starter. It held for about a year.

It was a very bad crack though, from a crackhead having straight water in it a couple years ago when we got a few -20 nights.

James

 

[rreegg]

If it's just some common junk and you gotta keep it rolling, that's what's up. I'd blue devil a 4.6 or 5.4 and run it till it dies. But our 6.9/7.3s require more dignity! I'd love be able to say to some unknowagable person, "my engine block is brazed". "BRAZED" doesn't that just sound classy?

Had to look it up for context but Blue Devil is a stop-leak brand, was getting it conflated with Blue Demon filler metals and initially though you were talking about welding things back

 

[Jesus Freak]

Had to look it up for context but Blue Devil is a stop-leak brand, was getting it conflated with Blue Demon filler metals and initially though you were talking about welding things back

Blue devil is legendary for head gasket sealing.

 

[Rdnck84_03]

Had to look it up for context but Blue Devil is a stop-leak brand, was getting it conflated with Blue Demon filler metals and initially though you were talking about welding things back

With the correct prep work and some nickel rod it can be welded. I have welded up differential housing before.

James