Leaking from head bolts

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PatrioticMopar

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Hey all,

I once again come to you seeking wisdom. The Duster project was ready to be started for camshaft break in. When doing a final prime on the oil pump, I noticed some antifreeze drips under the car. I have tracked the leak to a couple of head bolts on both sides.

This 318 motor came with the car when I bought it and had just been rebuilt. It is a 1972 LA engine. I am assuming they did not use thread sealant on the head bolts. So my questions are...

1) Does anyone know specifically what head bolts access water jackets on the 318 LA?

2) Can I remove the headers and just thread seal one bolt at a time, or do I need to tear it down to the heads to sequence the torquing?

3) Will the head gasket need to be replaced after breaking the original torque and seal on those head bolts?

thanks in advance!
 
I would pull one at a time honestly. I can't remember off the top of my head which bolts aren't blind. Why do you need to remove the header? Just pull the valve cover, remove the rocker assembly and redo the head bolts. Make sure to drain the coolant first.
 
I don't believe any of the head bolts go through the water jackets on the LA engines. Truthfully, I've never used sealant on the head bolts and never had an issue! I'd make sure the leaks aren't coming from the header bolts because they do go into the water jackets. 65'
 
Check the date on the block. I forget what year it started, but Chrysler went cheap **** and removed a bunch of metal from the blocks. When they did that, the head bolts were no longer blind like they should be and they broke through to water.

Pull any head bolt (or a couple) and stick a piece of wire down the hole. If it doesn’t bottom out, you need to pull them all, apply sealer and install them.

If you have an early block and it’s leaking from the head bolts you have other issues, because those holes are blind.
 
I don't believe any of the head bolts go through the water jackets on the LA engines. Truthfully, I've never used sealant on the head bolts and never had an issue! I'd make sure the leaks aren't coming from the header bolts because they do go into the water jackets. 65'
I was always under that assumption too, but I've heard several people say that a few of the head bolts aren't blind. Like you, I've never put any sealant on the bolts and haven't had a problem with them.
 
Check the date on the block. I forget what year it started, but Chrysler went cheap **** and removed a bunch of metal from the blocks. When they did that, the head bolts were no longer blind like they should be and they broke through to water.

Pull any head bolt (or a couple) and stick a piece of wire down the hole. If it doesn’t bottom out, you need to pull them all, apply sealer and install them.

If you have an early block and it’s leaking from the head bolts you have other issues, because those holes are blind.
He said it was a '72. The odd thing is, my '89 block and my '68 block don't have sealant on the threads and neither leaks. But that's interested if it is breaking through to water.
 
I've seen 318s from all years from the 1970s onward with blind head bolts and wet head bolt holes. Most have been open in the deck towards the valley but some have been open on the exhaust side of the head. I think it was more which plant they were being cast at and when more than it was a corporate wide policy on iron reduction. I have noticed it is always in higher dash numbers (coring mold revision) blocks than in lower numbers. Most have been -12 and higher.
 
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I don't believe any of the head bolts go through the water jackets on the LA engines. Truthfully, I've never used sealant on the head bolts and never had an issue! I'd make sure the leaks aren't coming from the header bolts because they do go into the water jackets. 65'
This discussion has come up before. SOME 318's have SOME wet bolts

I was called out for "faking" this photo. It is not a fake

mt1r93-jpg-jpg.jpg


I don't believe ANY 360/340 has wet bolts.
 
Taking a good look at this. I am in the process of rebuilding my '72 318.
Off topic, I also know what it is like to be called out as BS. I said that my choke heat stove worked just fine on my six-pack. I have Trick Flow heads, no path for exhaust crossover. My choke works just like it's supposed to thankyou.
 
I would pull one at a time honestly. I can't remember off the top of my head which bolts aren't blind. Why do you need to remove the header? Just pull the valve cover, remove the rocker assembly and redo the head bolts. Make sure to drain the coolant first.

The flange on the header prevents me from putting a socket on the exhaust side bolts unfortunately
 
I've seen 318s from all years from the 1970s onward with blind head bolts and wet head bolt holes. Most have been open in the deck towards the valley but some have been open on the exhaust side of the head. I think it was more which plant they were being cast at and when more than it was a corporate wide policy on iron reduction. I have noticed it is always in higher dash numbers (coring mold revision) blocks than in lower numbers. Most have been -12 and higher.
Good to know... I’ll look through my old photos for the block number on this one. I know it decoded to a 72, but don’t remember anything else
 
But I will likely be disassembling lol

Asking as we had a 340 leaking from the heads last summer. Cometic MLS were used. We pulled the heads, put felpros on it and stopped leaking. My brother builds vintage Cosworth racing engines (70’s formula 1, F2 and the such) and only uses Cometics, he recommends putting a little RTV around the water ports on each layer of the gasket, along with copper coating the mating faces. If bolts are into wet ports, thread sealant is necessary when assemblying...
 
Asking as we had a 340 leaking from the heads last summer. Cometic MLS were used. We pulled the heads, put felpros on it and stopped leaking. My brother builds vintage Cosworth racing engines (70’s formula 1, F2 and the such) and only uses Cometics, he recommends putting a little RTV around the water ports on each layer of the gasket, along with copper coating the mating faces. If bolts are into wet ports, thread sealant is necessary when assemblying...
Thanks for the info... I’ll be putting sealant on all these little bastards lol
 
This discussion has come up before. SOME 318's have SOME wet bolts

I was called out for "faking" this photo. It is not a fake

View attachment 1715708571

I don't believe ANY 360/340 has wet bolts.

Yup. It's a random thing. And yes, I have seen some 360s with wet head bolts, but not a 340 as of yet. So far, every 318 I've seen had wet head bolts.

I would pull them one at a time and seal them with red high temp RTV and put them back and re-torque them one at a time. You'll never have them leak again. However, you'll want to drain the coolant completely and blow dry each hole with compressed air first.
 
Yup. It's a random thing. And yes, I have seen some 360s with wet head bolts, but not a 340 as of yet. So far, every 318 I've seen had wet head bolts.

I would pull them one at a time and seal them with red high temp RTV and put them back and re-torque them one at a time. You'll never have them leak again. However, you'll want to drain the coolant completely and blow dry each hole with compressed air first.
Thanks :thumbsup:
 
Double check to make sure it’s not the header bolts.
Do one head bolt at a time. Remove one , clean it , seal it , Torque it. Next one .....
no prob
 
Yup. It's a random thing. And yes, I have seen some 360s with wet head bolts, but not a 340 as of yet. So far, every 318 I've seen had wet head bolts.

I would pull them one at a time and seal them with red high temp RTV and put them back and re-torque them one at a time. You'll never have them leak again. However, you'll want to drain the coolant completely and blow dry each hole with compressed air first.

Rather than RTV, I'd use liquid Teflon pipe thread sealant, blow dry is a good idea, be careful of blow back
 
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