Coolant in cylinder 8 on 318

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thecatsfan

thecatsfan

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Trying to help my sister get her 67 Barracuda back on the road. She bought a crate 318 during COVID. I finally got the opportunity to put it in the car for her over the winter. Got all the way to filling fluids, priming oil, and getting ready to install the intermediate shaft and distributor. Turned the engine over very briefly without spark plugs and see coolant coming out of spark plug hole for cylinder 8. This is a long block that was fully assembled, and supposedly bench tested. Pull the intake thinking maybe something is leaking there. Seemed unlikely but obvious place to start. Nothing. Gaskets and silicone around water jackets look well sealed. What else could it be? Head gasket?

Bit the bullet and pull the head, and nothing visibly obvious there. I am stumped. Has anyone ever seen coolant in one cylinder like that? No idea how coolant is getting pulled into that cylinder.

Edited: Obviously one of the things I instantly thought of was a cracked block. But this engine has new sleeves, so I don't think that is even a possibility.

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Do a cylinder leak down test just put air in cylinder with valves closed ,you can level engine and fill block with water and look for bubbles coming from water jacket with intake off ,on another note make sure your intake bolts are not to long and bottom out in the end holes they may feel tight will bottom out and NOT compress the gasket
 
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teringer said:
Do a cylinder leak down test just put air in cylinder with valves closed ,you can level engine and fill block with water and look for bubbles coming from water jacket with intake off ,on another note make sure your intake bolts are not to long and bottom out in the end holes they may feel tight will bottom out and NOT compress the gasket
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Reassembling far enough to do a leak down test is probably the best next step if I cannot visibly find anything.

Intake was well sealed, and coolant was definitely not coming from intake side. Intake runner was bone dry.
 
Warped head or deck, cracked head. Gonna have to pull it down.
 
So, here is a question. This is a newer LA block - early 80s. The head bolt holes are not blind. 9 of the 10 actually go into the water jacket. Should there be sealer on these bolts?
 
Cant see, what intake gaskets were used? It can happen, using metal gaskets, water port near intake port, short circuit.
 
i don't mean to question your mechanical prowess, but... are you sure it was coming out of the cylinder and not the exhaust stud that's right next to it?

i only ask because that stud is so close and it is wet.
 
Might be dribbling out of the last exhaust stud in the head since the two end holes on each head go through to water. Where "I" would start first would be a pressure test to the cooling system. That will tell you pretty quickly.
 
thecatsfan said:
So, here is a question. This is a newer LA block - early 80s. The head bolt holes are not blind. 9 of the 10 actually go into the water jacket. Should there be sealer on these bolts?
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Yes, but it shouldn't be getting through there and the head gasket just filling it up, no way.
 
That is a lot of coolant, if it is exiting the spark plug hole. Remove the head & the problem should be obvious.....
 
The head is off, and there is nothing obvious. I thought the same thing. Was really expecting a visible problem with head gasket or something like that.
 
RustyRatRod said:
Might be dribbling out of the last exhaust stud in the head since the two end holes on each head go through to water. Where "I" would start first would be a pressure test to the cooling system. That will tell you pretty quickly.
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A pressure test is where I should have started. But the leak was enough that I expected to find something obvious, and just started disassembling to find it. And found nothing. Good news is with a new sleeved cylinder, I can pretty much rule out the block. Think I am going to have the head tested since it is off. Then I am down to just making sure the head gasket is properly installed, torqued and everything well sealed.
 
thecatsfan said:
A pressure test is where I should have started. But the leak was enough that I expected to find something obvious, and just started disassembling to find it. And found nothing. Good news is with a new sleeved cylinder, I can pretty much rule out the block. Think I am going to have the head tested since it is off. Then I am down to just making sure the head gasket is properly installed, torqued and everything well sealed.
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Well, the problem there is "pretty much" ain't "good enough". Have you got the head off yet? Hopefully something obvious will jump out at you. I'm lazy at back reading. Is the sleeve in #8? If so, that would be HIGH on my list of suspects.

Ok, I back read TWO posts and see you have the head off. lol If nothing obvious, I would be really leery of #8 if that's where the sleeve is. You can still have it pressure tested, but at this point, it will need to be a bare block to get that done.
 
This could be something simple as, while it was being disassemble after the bench testing maybe some antifreeze could have spilled into the intake. Such as the upper coolant hose, which can hold a fair amount of antifreeze on a hurried removal.
 
RustyRatRod said:
Well, the problem there is "pretty much" ain't "good enough". Have you got the head off yet? Hopefully something obvious will jump out at you. I'm lazy at back reading. Is the sleeve in #8? If so, that would be HIGH on my list of suspects.

Ok, I back read TWO posts and see you have the head off. lol If nothing obvious, I would be really leery of #8 if that's where the sleeve is. You can still have it pressure tested, but at this point, it will need to be a bare block to get that done.
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Every cylinder is sleeved, unless I am losing my mind. Unless later blocks came sleeved from the factory - which could be. I do not claim to know all the different engines Mopar made well.

It does look to me like the head gasket was barely compressed.

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Dicer said:
This could be something simple as, while it was being disassemble after the bench testing maybe some antifreeze could have spilled into the intake. Such as the upper coolant hose, which can hold a fair amount of antifreeze on a hurried removal.
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It was pressure tested on the bench, not run tested. They never even installed a water pump. They have a machine that will turn the crank and read cylinder pressures etc. There definitely was no liquid anywhere in this block except assembly lube until I dropped it in.
 
No one that I’ve ever heard of has sleeved 8 holes on a 318, at that point you’d just get another 318 block. (Factory x or r blocks stamped 318 need not apply). I think you mean bored when rebuilt which could still mean it has a cracked cylinder.
 
is that gasket still on there? if so, then the "sleeves" you're thinking that you see are just the fire rings of the gasket.

pull that mess off and let's see some better pics.
 
AJ/FormS said:
Check the head then, they have been known to crack. To pressure test the head, you sorta need to take it to an engine shop which has a fixture to do that quick and easy.
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I am dropping the head off at a local machine shop tomorrow morning to have them pressure test it.
 
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