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Coolant from exhaust header stud bolt

OzCharger69

OzCharger69

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Hello Mopar family,

I am hoping you can help me with a bit of a headache coolant leak. I had quite a few coolant leaks from the header bolts. I took them out and re-installed with thread sealant. That took care of all of them bar the one seen in the video. I pulled it out again, reapplied the loctite thread sealant for a second time and torqued it down. I let it dry for 5 days before putting coolant in and the leak is even worse now.

The threads are clean and undamaged. I am thinking of installing longed bolts because the stud bolts are fairly short. Any ideas?

 
Studs don't really get torqued. Does the hole have a crack? Those head threads should be clean and dry. Use high temp thread sealer, though it's in a water jacket, it is next to an exhaust port. I use a Permatex product. Not in the shop to give you a number.
 
I watched your video and that looks like a pretty serious leak. I think the longer studs are a good idea and I would give that a shot. Like Bird says, above, I think there might be a crack in in the head.
 
Looks like you are using bolts.
I use studs in all the holes but one.
I use orange RTV on the threads.
 
Yup one of my pet peeves with Mopar heads, what mental midget decided to have exhaust bolts strike water is beyond me... kinda like the guy who designed square nuts :fool:
If you cleaned the threads really well and applied some sealant and it still leaks then it is a good chance you've got a crack around the threads. If so it's a great excuse to pop on some aluminum heads and forget about it. Not sure what the availability is for some stock heads in Australia but with the cost being competitive for some aluminum heads verses cast iron I'd opt out for some light weights unless your interested with keeping stock appearances. Loosing 100lbs off the nose of your car can't be all bad...IMO
 
Last edited:
Many thanks for all your replies.

I'll clean the threads really well and try longer bolts. That failing, I'll dig deeper.

Aluminium heads sounds very appetising too.
 
Loctite is not a thread sealant. Try some Permatex one or two. If that doesn't work throw a teaspoon of instant porridge or a few ounces of Bars block sealant into the radiator and give it a bit of time to do it's thing.
 
Back in the day when ‘67 HP closed chamber heads were the hot ticket, I broke off a stud flush on one of the heads. I took it to a guy that burned it out with a torch. Then it leaked like hell. I took it to another shop and the machinist drilled it out, and tapped it for a pipe plug. He then tapped that fresh and with anti seize it never leaked again.

Btw… I used header bolts with the 12 side head. I imagine studs would work as well with anti seize.
 
I have fixed minor leaks just by installing the original exhaust manifold stud.

The leak you have is a little worse, but I would still try it.
 
I wrapped teflon thread tape on mine and then applied RTV sealer to the outside of the tape.
Worked out good.
 
I'd remove the header and do a close inspection of that hole. If it has a crack you might be chasing your tail. If it is cracked you might be able to repair it in the car.
 
steve340 said:
I wrapped teflon thread tape on mine and then applied RTV sealer to the outside of the tape.
Worked out good.
Click to expand...

I used teflon tape on my header bolts as far back as the 80s...... never had a problem

I put that sh!t on everything :D
 
Permatex #2 never totally hardens. It's almost like pipe dope. No silicone, more of a tar substance. It's been around a lot longer than me.
 
The thread sealant I used was for a high temp application

Loctite 592 High Temperature Thread Sealant 50mL

The studs I have look short to me, 3/8" long. I have longer bolts and I'll try that first and if that fails, the headers are coming off.

WhatsApp Image 2024-05-11 at 19.09.41_8d63700d.jpg
 
The water jackets should have studs, do you want to.go through this process every time you remove the header?
 
Headers are off. The threads look good to me with no cracks. I added a few pics, maybe someone can spot something I'm missing?

At this stage I suspect the culprit is the second bolt from the front. Longer Bolts on the way.

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