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Where are the 318 gurus? coolant leak!

J

Jordan L

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Hello,

Just picked up a new to me 68 Coronet. She runs great, been sitting for a while, and after the drive home, I noticed a coolant leak. While working on cars and motorcycles are not new to me, but id like to ask the 318 gurus here before I dive in.

Seems like its leaking from this bolt? is it a wet bolt and goes into a water jacket? if so, what are you guys using? RTV sealant? Teflon tape? Or is there a rubber gasket behind this bolt?

It's leaking on the passenger side head too, same bolt as well...at least it looks like it, but not as bad as driver side. Hoping this isn't too big of a deal

I was trying to find a parts diagram for the 318 so I could take a look but no luck

Thanks for the input

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Those are suppose to be press in freeze plugs. Those are aftermarket type expansion plugs I believe. You can get the 1968 parts book from MyMopar.com under tools and references.
 
Yup thats one of those temporary fix freeze plugs. Time to put a brass one in. At least its up front where you can work on it. Once you remove the rubber plug look inside see how clean it is. Now might be the time to back flush everything before putting a metal plug in. Make sure there are no gouges in the surface area where the fp sita. Get some Indian head gasket shellac put a light coating on the lip of the plug and drive it home. Usually an old socket that fits inside of the lip is sufficient to install it. Trick is to set it evenly in the hole.
 
Do you guys have the size off the top of your head?

I found a freeze plug kit for the 318 on summit but doesnt include the head freeze plugs, the ones i need
 
1 5/16" i believe. Local parts store should be able to get you a couple without buying a whole kit
 
Get the brass "deep" ones.

Better seal, and last longer.
 
It is either 1" or 1.25", I would have to check tomorrow at work. But, do get RID of that rubber POS for the correct plug. The other thing I see that disturbs me, and might not be noticed by most people, is the heat tab. Just above the corrugated hose, on the block plug is what we call a heat tab. After we (machine shops) perform work, most of us apply a heat tab that is designed to melt out the center (lead) above 265 degrees F. You can clearly see the inner circle whick means the motor has overheated at least once, and melted the center out. Likely the leaking freeze plug was replaced after the overheat, with the rubber POS. Hope this helps...
 
69Bee said:
It is either 1" or 1.25", I would have to check tomorrow at work. But, do get RID of that rubber POS for the correct plug. The other thing I see that disturbs me, and might not be noticed by most people, is the heat tab. Just above the corrugated hose, on the block plug is what we call a heat tab. After we (machine shops) perform work, most of us apply a heat tab that is designed to melt out the center (lead) above 265 degrees F. You can clearly see the inner circle whick means the motor has overheated at least once, and melted the center out. Likely the leaking freeze plug was replaced after the overheat, with the rubber POS. Hope this helps...
Click to expand...

If your looking for a 318 Guru then you have found one. Dave knows these engines inside and out.
 
Last edited:
69Bee said:
It is either 1" or 1.25", I would have to check tomorrow at work. But, do get RID of that rubber POS for the correct plug. The other thing I see that disturbs me, and might not be noticed by most people, is the heat tab. Just above the corrugated hose, on the block plug is what we call a heat tab. After we (machine shops) perform work, most of us apply a heat tab that is designed to melt out the center (lead) above 265 degrees F. You can clearly see the inner circle whick means the motor has overheated at least once, and melted the center out. Likely the leaking freeze plug was replaced after the overheat, with the rubber POS. Hope this helps...
Click to expand...

Cool let me know the size thanks! Stop by my local auto parts store and they only had rubber ones...
 
As stated, 1.25", and respecting ColoradoDaves comment, I prefer steel as opposed to brass. If brass is not put in straight, it can become deformed and not seal properly, even to the point of falling out. The Pioneer number for a steel deep plug is EPC18, brass is EPC18B. A steel shallow plug is EPS110, and brass is EPS110B. Deep plugs help with alignment issues.
 
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