Coolant leaking into 318 cylinder 8

-

thecatsfan

Well-Known Member
Joined
Jul 18, 2019
Messages
71
Reaction score
53
Location
Loveland, Colorado
Purchased a complete 318 long block remanufactured engine during COVID. Project got tabled for a while. Recently got to the point we were ready to fire the engine for the first time. Was about to install the intermediate shaft and distributor. Fortunately, we had the plugs out to make it easier to turn the engine by hand. While turning the engine, we noticed coolant coming out of the spark plug hole from cylinder 8.

Instantly starting thinking cracked head, torn head gasket, leaking intake manifold gasket - all the obvious possible things that it could be - and of course, cracked block. But this was a freshly machined block. Sent a borescope down the intake runner and into the cylinder - nothing visible. Intake is dry as a bone. Started assuming it had to be top end, so I pulled the top end apart. Could not find anything. Had the head tested. Tested perfect. So I reassembled, and hoped it was just the head gasket. Nope. Turned the engine and there is coolant in cylinder 8. Sent the borescope back in, and figured out that if you pull the piston all the way down, coolant starts running in from the bottom. Pull the cylinder up a little bit, and it stops. Coolant is entering from below the piston line. Best guess now is that the cylinder is cracked, but so deep in the hole, that it is below the rings until the very bottom of the stroke. Frustrating. Engine has never been run. I already checked all the obvious questions. No it is not weeping in from the exhaust hole. All intake bolts, and outer exhaust bolts were properly sealed. The engine passes a leakdown test when the cylinders are at TDC. The coolant is definitely coming from below.

Have already sourced another block, but it needs to be machined. Will be pulling the engine this weekend, and pulling the piston out of cylinder 8.

Here is a video of the inside of the cylinder. Most frustrating thing I have ever dealt with.
 
Depending on exactly how far down the hole is, it may be cheaper to have a sleeve installed in that hole, as opposed to machining another block from scratch.
 
so this is where you are after you left off here:


nice to know you found the source of the leak.

as to repair... how much work are you capable of? or willing to do? you could sleeve that one hole, but that means a FULL tear down, which in the grand scheme of things... isn't the most awfulest thing around.

as @PRH said, it may be cheaper to have just the one done, but they still have set up and everything else to get there-- for instance my guy charges $80 a sleeve, but that's inclusive to other machine processes already taking place ie. boring, and decking. so you'd have to talk to your machinist about that. maybe they take mercy on your soul (and pocket book).

however, more to the point... it's 60 over and this one is a problem now. who's to say them other sevens aren't going to exhibit a problem after start up, some heat cycles, a few thousand miles, etc.

weigh that against what a reman short block would run ya and see where the chips fall.
 
Not to mention, sleeving the one cylinder WILL distort the cylinder next to it, that is presumably allready honed to the proper size. Looks to be allready .060 over, I'd chuck it in the scrap bin and start over.
 
If you were closer I would give you a std 318 bare block.
 
At this point, I have no faith in the block. I found a 1967 complete engine, minus the heads, that has never been torn down. I already have it down to the bare block, and will have a local shop go through it completely. I have wasted FAR too much time and money on this project to take shortcuts now.

They will clean it, test it, bore it, deck it, and have it ready to install parts. I am going to use the new pistons, new cam, etc. from the remanned engine. I will probably even use the crank, as my local shop does not turn cranks. Too bad though. This 67 block has a forged steel crank in it.


The only good news. The block I found is a 1967 block, and the car is a 1967 Barracuda. So at least it is now a year matching block.
 
Last edited:
So, the old block is no good because it’s .060 over……..but you’re boring the replacement block .060 over, so you can reuse the pistons.
 
So, the old block is no good because it’s .060 over……..but you’re boring the replacement block .060 over, so you can reuse the pistons.

I have no faith in this block because I do not assume what caused the crack. I definitely do not assume they bored the cylinder holes too thin. For all I know it was frozen, or otherwise stressed, and other problems simply have not shown up yet. If the remanufacturer missed one defect, how many others are barely hidden? The coolant system was not even pressurized. It has never been fired, never been warm, never had coolant pressure. And already had a hole leaking into a cylinder. .060" over bore is very common on 318s. Sure, there are probably some blocks out there too thin to handle it. Some guys have gone to a 4" bore on 318 blocks.

Honestly, the question is not why would I scrap it. The question is, why would I trust it?

Also, this is a 1984 block. It appears they used less metal. 9 of the 10 head studs are wet holes on this block. None of them are wet on the 67 block. Unless someone drilled all the head studs through to the water jacket, this seems to be a block with less metal in it.

The cost to sleeve one cylinder, then bore it, hone it, check the adjacent cylinder and possibly have to clean it up, then deck the block again, is not going to be cheap. It is not going to save me a ton of cash over machining an entire block. It is a nominal cost savings to risk finding other issues with the block. And I will have the block sonic tested before it is bored. If I have to buy pistons, I have a brand new unused set of .060 pistons I can sell, and recoup a little cash.
 
Last edited:
As a rule the LA block can go .040 over. I know its a subject of debate but I've always remembered that .040 for some reason.
 
As a rule the LA block can go .040 over. I know its a subject of debate but I've always remembered that .040 for some reason.
Remember that doesn't take into any consideration for how much corrosion there is inside the water jackets. And all it takes is a pin hole. His block would have leaked at .040 just as easy.
 
When I had the 'Killer6' block done .060" over in '86, one hole was porous, & had to be sleeved. That block would've been ~20yrs old at that point, now it is pushin' 60, time is not kind....and flawed castings are still out there waiting to be "discovered".
Every old mill should be sonic checked & pressure tested. Luckily, Carl spotted the warning sign as He progressed, & sent Mark over to let Me know & decide.
 
I know bore size has been debated to death. Search this forum or a Google search and that debate has been going on for years. Some guys say .040". Some guys say more.

With an unmolested block, at least I have something to build from. I will trust my shop to tell me if it can or cannot handle going .060" over. Right now I have a $4K paperweight and I have to move forward with something.
 
Warranty is expired already, and when I contacted them, they did not even answer my email.
It was never used, if it was something else I would understand, but this is an engine. You will be surprised that depending on the situation, some people have too much pride in their work and will fix an issue like this just to keep a good reputation. (They might not cover 100% and there may be other compromises, but it's better than nothing.)

If they don't fix it, document everything, take lots of good photos and give them a negative review everywhere. If they f**ked this motor job up, who knows how many more they did?

Also, contact them via telephone.
 
It was never used, if it was something else I would understand, but this is an engine. You will be surprised that depending on the situation, some people have too much pride in their work and will fix an issue like this just to keep a good reputation. (They might not cover 100% and there may be other compromises, but it's better than nothing.)

If they don't fix it, document everything, take lots of good photos and give them a negative review everywhere. If they f**ked this motor job up, who knows how many more they did?

Also, contact them via telephone.


Won’t matter if he calls them or sues them. The laws on this were settled long ago.

The warranty is what it is and it’s in writing. Implied Consent law covers this too.

Obviously if he calls them and explains to them the circumstances they MIGHT, MAYBE, COULD help him out.

But I doubt it and it is worth a try.

I’ve questioned these warranties and called the lawyer that wrote out the warranty where I worked at the time and he told all of us the warranty was iron clad.

We got sued twice while I was there. Didn’t lose either.
 
get another block and swap the innards over...its a 318 right ? still a dime a dozen basically... there is no major monetary loss IMO that cant be recouped .
 
Put a sleeve in it and go.

Anything else and you are just wasting money for no good reason.
Sleeving the engine is just as much work as a new block and similar cost. To sleeve the engine, I have to tear it down to completely bare. The shop will not touch it otherwise. The shop will have to sleeve it, bore it, hone it, check adjacent cylinders, redeck the block. I already talked to the shop about it, and they said I am looking at minimal cost difference.
 
Last edited:
It was never used, if it was something else I would understand, but this is an engine. You will be surprised that depending on the situation, some people have too much pride in their work and will fix an issue like this just to keep a good reputation. (They might not cover 100% and there may be other compromises, but it's better than nothing.)

If they don't fix it, document everything, take lots of good photos and give them a negative review everywhere. If they f**ked this motor job up, who knows how many more they did?

Also, contact them via telephone.

I am not saying you are wrong. I am saying, I don't want to play this game twice. And I am not a big fan of fool me twice. I really do appreciate your advice and perspective. The story is a lot longer with the entire project than I will bother you with.

I have a block from a running engine, and am already on my way down that path.
 
I am not saying you are wrong. I am saying, I don't want to play this game twice. And I am not a big fan of fool me twice. I really do appreciate your advice and perspective. The story is a lot longer with the entire project than I will bother you with.

I have a block from a running engine, and am already on my way down that path.
Your doing the right thing. Those mid 80s 318 blocks are crap anyway. Almost every one I have looked at are cracked on the deck surface to those open head bolt holes. They are THIN. Sell off those cheap rebuilder .060 pistons and bore the replacement block the min required to clean up.
 
-
Back
Top