Cracked block - what to do?

[CO MJ]

I was real confident I had antifreeze in my coolant, apparently not. Blew a hole in one of my freeze plugs, but the only leak I could see was coming out of the hole in the plug. I thought I got lucky and went to replace it today, started to press it in and noticed a drip on my shirt, put a light up in there and it looks like a nice big crack under the second freeze plug. Not sure why it only now decided to start leaking.

 

I know for a fact I already had exhaust gas in my coolant already, presumably a crack or leak somewhere in the cooling jacket, and I planned on driving this engine into the ground, but it runs just fine and I was hoping it would be something less stupid than forgetting antifreeze that killed her. 

Is this even worth considering repair? In my head, if the engine comes out, I will only put a new one back in, but money is also a factor.

If I'm really done and I need a new block, where are people getting reman engines these days? Does it matter what year or vehicle it comes out of? I have a renix 4.0 as is. Not sure I have it in me to pull an engine from a yard, but what are feelings about that? Worth rebuilding before installing?

 

[eaglescout526]

36 minutes ago, CO MJ said:

was real confident I had antifreeze in my coolant, apparently not

Haha, sorry I couldn’t help but laugh a little. I presume you mean oil in your coolant. Because those two are the same thing in the automotive world. 

[89 MJ]

29 minutes ago, eaglescout526 said:

Haha, sorry I couldn’t help but laugh a little. I presume you mean oil in your coolant. Because those two are the same thing in the automotive world. 

I think he means that he only had water in the cooling system based on this:

1 hour ago, CO MJ said:

I was hoping it would be something less stupid than forgetting antifreeze that killed her

 

 

I have no issues with putting used engines in my vehicles, however I am quite particular about them. I do not rebuild them, but I like for them to have around or less than 125,000 miles on them. I also will not buy one without hearing it run first to verify that it does not smoke or knock. I'll typically do intake, exhaust, valve cover, and oil pan gaskets while they're out. I also like to clean and paint them, but that's pretty optional. 

[CO MJ]

14 minutes ago, 89 MJ said:

I think he means that he only had water in the cooling system based on this:

 

 

I have no issues with putting used engines in my vehicles, however I am quite particular about them. I do not rebuild them, but I like for them to have around or less than 125,000 miles on them. I also will not buy one without hearing it run first to verify that it does not smoke or knock. I'll typically do intake, exhaust, valve cover, and oil pan gaskets while they're out. I also like to clean and paint them, but that's pretty optional. 

ah yeah water only

That's also my concern since you can't start anything up in a yard, even with the 30 days or whatever they typically give you, what a nightmare it would be to pull and install it just to find out it has significant issues and having to bring it back to the yard. Unfortunately I don't have any space to take a doner vehicle, so i think buying a pulled and tested engine or a reman unit is the only way I'll be able to do it confidently, and the used engines don't seem to be significantly cheaper than a reman long block unfortunately

[gogmorgo]

That’s a tough spot for a fix. I have a 2.5 with a crack in the same spot, right by the motor mount. It pulls it open when you rev the engine. Took me a while to find the leak because it would only release any pressure while on the throttle when the crack would open up.

This is probably due more to stress over time and possibly a casting defect than a freezing issue.

 

I used a block repair in a can type of product and it stopped it leaking for a bit, but not a permanent fix. I dumped a regular stop leak product in it for a temporary fix while having the truck shipped a little over a year ago and it hasn’t started leaking from the crack again but I’ve had to flush plugs of stop leak out of my heater core three times now.

 

Engine block cracks can be welded carefully under the right conditions. There’s also a time consuming technique of drilling and tapping a hole at the end of the crack for a tapered pipe plug, drilling and tapping another hole overlapping the first plug and so on until you’ve covered the entire length of the crack with overlapping tapered plugs. 

 

But if there’s other apparent issues with the engine that would indicate a rebuild is imminent, it may better to find another engine to rebuild instead.

 

I also don’t have much issue with a used replacement. I’d be more inclined to buy a complete but rotten donor vehicle that I can start and drive than to get a junkyard engine, but if you’re paying someone else to do it one engine swap is a fair bit cheaper than two. And if you’re struggling to find a Renix engine, Cruiser54.com has a tip for dropping in an HO.

 

And I knew what you meant when you said antifreeze in the coolant. Coolant is the juice that flows through the cooling system, whether that juice happens to have an antifreeze additive in it or is just muddy river water is pretty irrelevant to its function as coolant. I’m all for pedantry but only when and where it matters.

[CO MJ]

43 minutes ago, gogmorgo said:

That’s a tough spot for a fix. I have a 2.5 with a crack in the same spot, right by the motor mount. It pulls it open when you rev the engine. Took me a while to find the leak because it would only release any pressure while on the throttle when the crack would open up.

This is probably due more to stress over time and possibly a casting defect than a freezing issue.

 

I used a block repair in a can type of product and it stopped it leaking for a bit, but not a permanent fix. I dumped a regular stop leak product in it for a temporary fix while having the truck shipped a little over a year ago and it hasn’t started leaking from the crack again but I’ve had to flush plugs of stop leak out of my heater core three times now.

 

Engine block cracks can be welded carefully under the right conditions. There’s also a time consuming technique of drilling and tapping a hole at the end of the crack for a tapered pipe plug, drilling and tapping another hole overlapping the first plug and so on until you’ve covered the entire length of the crack with overlapping tapered plugs. 

 

But if there’s other apparent issues with the engine that would indicate a rebuild is imminent, it may better to find another engine to rebuild instead.

 

I also don’t have much issue with a used replacement. I’d be more inclined to buy a complete but rotten donor vehicle that I can start and drive than to get a junkyard engine, but if you’re paying someone else to do it one engine swap is a fair bit cheaper than two. And if you’re struggling to find a Renix engine, Cruiser54.com has a tip for dropping in an HO.

 

And I knew what you meant when you said antifreeze in the coolant. Coolant is the juice that flows through the cooling system, whether that juice happens to have an antifreeze additive in it or is just muddy river water is pretty irrelevant to its function as coolant. I’m all for pedantry but only when and where it matters.

Definitely possible it was already there, we just had our first freeze of the year and I just assumed that was the cause since it also popped one of the expansion plugs. Either way, it's leaking just sitting in the drive so I guess I'll need to address it. If I can get that plug back in without pulling the intake/exhaust I may just try to keep it going for a while and just keep the coolant topped off until I can get around to swapping in a new block, but if it keeps leaking like this I think she's done for.

 

Unfortunately I don't think my landlord would approve of a doner in the driveway so I think it'll have to be a reman long block or gamble on a junkyard unit

[89 MJ]

4 minutes ago, CO MJ said:

Unfortunately I don't think my landlord would approve of a doner in the driveway so I think it'll have to be a reman long block or gamble on a junkyard unit

In that case, I think a reman unit might be the better way to go. You won’t have to clean it or worry about it having issues, it can be dropped in and ran. Plus it’ll have a warranty. 

[CO MJ]

1 hour ago, 89 MJ said:

In that case, I think a reman unit might be the better way to go. You won’t have to clean it or worry about it having issues, it can be dropped in and ran. Plus it’ll have a warranty. 

$500 plus bits and pieces from the junkyard vs $2500 and unknown lead time from a remanufacturer is quite the difference though, I'll have to think on it. May attempt the jb weld and put some stop leak in it just to see how many more miles I can squeeze out of her

[89 MJ]

16 minutes ago, CO MJ said:

May attempt the jb weld and put some stop leak in it just to see how many more miles I can squeeze out of her

This is probably the route I'd go until it warms up. It also gives time to save some money. When I did the swap, I had a little over $600 in bits and pieces, but I know I can go overboard when doing things like this. 

[gogmorgo]

I did an engine swap on my back lawn at a rental place about ten years ago. I hauled home a $350 rotten no papers but good running XJ, parked it next to the MJ, threw down a couple sheets of plywood to roll the engine crane around on. Took me about a week of evenings after work to get everything swapped over, maybe including the Saturdays to get everything buttoned up. I swapped engine trans and tcase together, likely wouldn’t have taken as long if I’d only moved the engine over, or if I wasn’t lone wolfing it. Then I donated the XJ shell to the local volunteer fire department for extraction practise, and they hauled it away for me.

I also watched some kids do an engine swap in a square body Chev in my college dorm parking lot, looked like they went from a straight six to a big block. They didn’t attempt to hide what was happening, spent a weekend on it, and didn’t make a mess. No one batted an eye as best as I could tell.