Exhaust Manifold Stud Sheared

[jimynick]

As several members have said, heat needs careful application. The secret to it is to apply a lot of heat in a short time to minimize the heat soak to the head. If you're not comfortable doing it, perhaps the best thing would be to take it to an exhaust shop, where they change/remove studs on a daily basis. They'll use a cutting tip or rosebud to max the heat and run it around the stud until the immediate area goes dull red and then you have to move quickly before it cools too much. They shouldn't charge you too much- $50 max would be my guess and it's a lot cheaper than buying torches/tools and then, still screwing it up. Good luck. 

[jforest1]

An update--I don't have any heat tools nor experience with them so in this case I'm gonna take it in to an exhaust shop with some pros in it that can remove it without fear. 

I, on the other hand, have nothing but at this point.

On the other end of this problem is replacing the hardware.  I've run into an issue where after running it for about 15 minutes and driving around, I've got coolant leaking out between the transmission bellhousing and the engine and dripping down the flywheel cover.  I checked both engine plugs where I drained the coolant and they are dry, so I've got to assume its because one of the studs that goes through the water jacket isn't in tight enough.

1st question:  if coolant is leaking through from the studs not being in far enough, what is getting wet now that doesn't normally and how do I alleviate?  mainly looking for direction here because as a I have no clue.

2nd question:  how tight is too tight?  I saw 120 inch/lbs in the maintenence manual, but am only now considering that might be for the bolts but not the studs themselves.  I need to double check, but I'm pretty sure the middle, unthreaded section was just proud of the engine head...

JF

[72cudamaan]

Another method that works extremely well is to heat the stud cherry red for about 45 seconds, as
soon as the stud dulls to a dark red, apply bees wax(not paraffin) to the stud. The process is this. When you heat the stud it expands.
 As it expands, it disrupts the rust formation. As it cools off, the heat will draw the bees wax into the threads.
You use bees wax as it has a higher melting point and better lubricating properties than paraffin. I have used
this method for close to 20 years with tremendous success. If you apply paraffin too soon, then it will just melt off and not be drawn into the threads.

[72rtchallenger]

An update--I don't have any heat tools nor experience with them so in this case I'm gonna take it in to an exhaust shop with some pros in it that can remove it without fear. 

I, on the other hand, have nothing but at this point.

On the other end of this problem is replacing the hardware.  I've run into an issue where after running it for about 15 minutes and driving around, I've got coolant leaking out between the transmission bellhousing and the engine and dripping down the flywheel cover.  I checked both engine plugs where I drained the coolant and they are dry, so I've got to assume its because one of the studs that goes through the water jacket isn't in tight enough.

1st question:  if coolant is leaking through from the studs not being in far enough, what is getting wet now that doesn't normally and how do I alleviate?  mainly looking for direction here because as a I have no clue.

2nd question:  how tight is too tight?  I saw 120 inch/lbs in the maintenence manual, but am only now considering that might be for the bolts but not the studs themselves.  I need to double check, but I'm pretty sure the middle, unthreaded section was just proud of the engine head...

JF

there are freeze plugs on the back of the block,that tend to rust out over the years,,of course you have to pull the tranny to access them,hope its not the problem but keep it in mind,and there is a freeze plug on each end of the heads,check those first for leaks,as far as the studs leaking ,if you have had the old ones replaced now you should be able to visually see if there is a leak after letting it warm up

[jimynick]

You don't need to torque the exhaust studs in the heads. Double nut 'em and run 'em in until they stop (assuming you're using oem studs) and give 'em a 1/4 more turn. Don't forget the thread sealant/teflon tape. Beg or borrow a straight edge and check the manifolds for flatness and have them fly-cut if over .030" approximately, warped. Use a good quality gasket and the stated torque specs for the manifold. The manifold studs have diddly to do with the coolant leaking out the back of the engine and as mentioned, you probably have a leaking frost plug in the rear of the block if you've determined that there's nothing blowing back to mimic the symptoms. Look at the good side, the exhaust will be a whole lot easier to work on when the engines out. 

[jforest1]

Look at the good side, the exhaust will be a whole lot easier to work on when the engines out. 

 

JF

[jimynick]

I hear ya buddy, I hear ya! But, and I mean it, better (by far) to find that leak now, rather on a dark, rainy night on the outskirts of B*tt F*** Idaho after the engine kaks due to coolant loss!

[jforest1]

Clinging to hope, I went ahead and removed the exhaust manifold and sure enough the rear passenger-side stud was not in far enough.  Because the front of the car was up on ramps, it ended up dripping down farther back than would be expected.

I'm pretty sure, at least, to be confirmed when I drive it around next and get the engine hot.

JF

[jforest1]

Confirmed no leak. 

I'm actually bowing out of this one and taking it to an exhaust shop to have them removed by someone who's done it a million times rather than my 0 for 0 record. 

I'll live to left-hand drill another day when I have a lower-cost item to try it on.

JF

[jforest1]

Ugh.  The leak came back and in a bad way!  Worse than ever and definitely the freeze plug on the block.   

JF

[72rtchallenger]

  ouch man