is there a certain optimal temp range where head bolts should be tightened?

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Old 01-05-10, 03:25 PM
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is there a certain optimal temp range where head bolts should be tightened?

My Dodge appears to have "blown" another head gasket when temp hit 20 below the other evening. Before this, engine temps were going up to H (before plummeting back to normal in seconds, after being at H)on the dash temp gauge - from an air bubble. I was concerned when that occured - but not overly concerned, since I never smelled hot coolant nor oil smells under the hood when it hit that mark, nor did the oil pressure on the oil gauge drop, which to my recollection happens when oil gets thinner due to the excessive heat. Nor did the engine ever stumble or feel like it was slowing down, from excess friction on the cylinder walls, from the pistons expanding. But I still had in the back of my mind that perhaps where the heat was occuring could cause uneven overheat, causing head warpage, possibly.

But this thought also occured to me: I bought the car used from this guy who said a new head(it looked like it too!) was installed about 10,000 miles before I bought the SOHC 4-banger Dodge. It now has only about 25,000 mile on that gasket. I have seen and actually have saved in my possession 2 blown head gaskets out of a 2.2L and a 2.5L (same head/gasket). Both of these rotted the metal cylinder ring built into the gaskets, on cyl. #1 and #4. What a bunch of junk! But antifreeze sitting in the engine can cause acidity that can work on these ferrous magnetic rings, along with the one side of the gasket touching cast iron, while the other side is touching aluminum. Not a very good combination of things here, if you ask me. A disaster by design, if you ask me.

But it still seems unlikely that after only this many miles that those metal rings inset in the head gasket would have rotted already. So I am thinking that if say the backyard mechanic that did the job tightened those head bolts to specs when it was 90 out, and the block and head were say larger in size.....that then when it got down to 20 below, perhaps the metal shrunk, and the head bolts are no longer crushing the gasket as good anymore.

The guys I just saw at the auto parts store did not buy my theory. So I am asking you guys what you think. I may try to retorque down the head bolts. But what can be trickly is you can get a false number read when the bolts are corroded in place or otherwise have goobered up threads that would increase the resistance to be tightened (Haynes Manual even talks about this). I would likely have to back out the bolts at least some, to get a feel of their ability to freely turn, and then retighten, to avoid a false read. And tighten them when it is like 0 out, because the weather we are having right now is what I'd be having in my ice-cold garage. Brrrr.
 
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Old 01-05-10, 05:37 PM
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'most' engines of newer design use a 'torque to yield' head bolt. it is a one time use head bolt.
the ring around the head gasket should be 'stainless' & not rott.
 
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Old 01-05-10, 06:43 PM
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Couple things running through my head, please bear with me.........Ecman says 2.2/2.5 .....so this ISN'T a fairly recent engine.....I'd still double check the one time use head bolt theory.....BUT .I'd definitely check the head for true........AND the BLOCK....just to be sure. Another last thought for the evening...........EGR.......If the valve is stuck closed, you get a cyl head overheat condition which may cause early demise of the head gasket...........That's my thinking for the evening sirs!!!
 
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Old 01-08-10, 03:13 PM
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Originally Posted by newtofta View Post
'most' engines of newer design use a 'torque to yield' head bolt. it is a one time use head bolt.
the ring around the head gasket should be 'stainless' & not rott.
So I wish they were. And if they ARE stainless, they are not stainless enough. They looked like a tin can buried in a farmer's backyard dump for 50 years.
 
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Old 01-08-10, 03:33 PM
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Originally Posted by wrench47 View Post
Couple things running through my head, please bear with me.........Ecman says 2.2/2.5 .....so this ISN'T a fairly recent engine.....I'd still double check the one time use head bolt theory.....BUT .I'd definitely check the head for true........AND the BLOCK....just to be sure. Another last thought for the evening...........EGR.......If the valve is stuck closed, you get a cyl head overheat condition which may cause early demise of the head gasket...........That's my thinking for the evening sirs!!!
Most interesting about the EGR theory.

On these stretch bolts, does one see any problem that if say they were torqued true to specs(when that shadetree mechanic did the head job) but then for whatever reason overheated and stretched more - that me loosening them, and then retightening would hurt? Or, maybe spend the $30 or so and buy new headbolts and change them out? Giving me the chance to chase the threads and make sure they get to the proper torque?

Sure is odd how the leak can come and go. I noticed some weeks back actually, before the obvious occured(billowing blue white smoke), that the upper hose puffed out under high pressure only a few minutes after idling the car! I thought then that that was abnormal. It is. That right there is the sign of a blown gasket or crack or warp. THEN I added a stop leak that says on the bottle it will permanently seal even large radiator, gaskets, head leaks, etc. So I dumped that in. Then I noticed that sometimes the upper hose would not get puffy until many miles down the road.

Right now what I do is relieve that pressure whenever I park somewhere for a while, in hopes that if the engine starts out not under that pressure and is warmed up, that the stop leak may have a better chance of staying jammed in the leak spot.

Days ago when this first occured, and before I added the stop leak, the engine misfired on one cylinder when I started it up cold. It did that 2 mornings in a row. Each time, the misfire went away in a matter of a few seconds. SINCE adding the stop leak, and doing what I do to collapse the puffy hose(by backing off the radiator cap partially, carefully, when hot, and squeezing in on the upper hose at the same time), it has not misfired.

A few mornings ago, it actually drew coolant back out of the reservoir, filling up the radiator to the top!(the way a closed coolant system is supposed to work) - which would indicate that at that moment, there could not have been a leak. I am always quite fascinated by unusual maladies like this.
 
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