Are new headbolts REALLY necesarry?
11-07-2006, 02:51 PM
#1
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Are new headbolts REALLY necesarry?
My girlfriends cousin is going to replace my blown headgasket on my 95 3.0 and he swears that new headbolts aren't necessary. I'm gonna let him do it, should I insist that he use new headbolts or let it go? Paul Oh yea he is a toyota tech.
11-07-2006, 03:03 PM
#3
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Absolutely YES.
Once you install a set you'll understand why. Torque to 33, then turn 90° and turn another 90°.
My torque wrench was reading over 112ft-lbs and clearly stretching the bolts.
They are torque to yield and do yield when you torque them down.
Do not under any circumstances reuse.
Once you install a set you'll understand why. Torque to 33, then turn 90° and turn another 90°.
My torque wrench was reading over 112ft-lbs and clearly stretching the bolts.
They are torque to yield and do yield when you torque them down.
Do not under any circumstances reuse.
11-07-2006, 03:03 PM
#4
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I reused mine, twice. First time after spinning a rod bearing, second time after blowing a head gasket (not because of head bolts, because of water pump failure). Never had any problems with reusing the bolts personally.
Edit:
Disclaimer: Though I am an idiot, it was the parts guy at the local stealership that told me new ones weren't necessary. Had I known they were, I would have used new ones.
Edit:
Disclaimer: Though I am an idiot, it was the parts guy at the local stealership that told me new ones weren't necessary. Had I known they were, I would have used new ones.
Last edited by Bassinfool; 11-07-2006 at 03:05 PM.
11-07-2006, 03:08 PM
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Well he is a toyota tech and claims it's not necesarry, although from what I've read on here it seems it is. I tried tellling him last night to use new headbolts and he assured me it wasn't necesarry. I'm leaning towards calling him and asking him to use them again but I don't want ot bug the guy about it before he fixes my car you know
11-07-2006, 03:13 PM
#6
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engbldr head bolts are like $30...
for the amount of time involved seems like really cheep thing to skimp on given what happens if they dont hold (like they are known to do an reuse)
for the amount of time involved seems like really cheep thing to skimp on given what happens if they dont hold (like they are known to do an reuse)
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11-07-2006, 03:59 PM
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Absolutley replace TTY bolts, they are designed to be used only once. It has something to do with stretch and compression (and to conpansate for temperature, contraction/expansion). Back in the day (before Torque To Yield) most heads required a re-torque after a certain mile/hour usage for the same reasons. If your tech refuses to use new bolts see if he will redo the job when (not if) it fails. For Free.
11-07-2006, 05:03 PM
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yea I called him tonight and left him a message....I'm gonna call him back in a few days, I told him last night that they were torque to yield but he said it didn't matter, He works for Toyota you'd think he'd know about it. On the other hand he told me that at the dealership all they do is replace the headgaskets and put it back together to the tune of 1500 bucks go figure
11-07-2006, 05:44 PM
#12
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the head bolts are torque to yield meaning that they are designed to be stretched to the point where they wont return to their origional form. All tty bolts should be replaced when removed. Its worth spending a few extre $ to save yourself many hours of work on down the road.
11-07-2006, 05:56 PM
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yea I know, it's just that I'm not doing it myself, My girlfriend's cousin, who happens to be a toyota technician is gonna do it. I dropped the car off last night and mentioned the need for new headbolts but he said I don't need them. It's gonna be a pain in the ass to convince this guy but it seems like I have to.
11-07-2006, 07:11 PM
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are you paying this guy to do this HG job? if so I would demand that he uses new bolts or like what dublin said will he replace the head again if it fails free of charge for the parts ect.
it is your truck and if he cant under stand that you dont want to take the risk down the road I would find someone else to fix it or help you fix it.
my.02 cents
it is your truck and if he cant under stand that you dont want to take the risk down the road I would find someone else to fix it or help you fix it.
my.02 cents
11-07-2006, 07:36 PM
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I'd change the headbolts. I don't know the exact theory behind why they use torque to yield bolts, but here's what's going to happen if you reuse them. When steel is stretched (or strained as it's called in engineering) past its yield point, you experience something that's called strain hardening. That means that the steel actually gets stronger. When you re-use your bolts, you actually have stronger bolts than your old ones. When you torque the headbolts up the specified torque, everything is the same. That extra quarter plus quarter turn will cause the same elongation or strain of the headbolts as before, but because the steel is stronger, the bolts give a higher downward force on the head. That means more force and pressure on the new headgasket, and I guess, it will make the headgasket more prone to breaking.
This is all just derived from my general engineering knowledge, so any additional info or corrections are very welcom.
This is all just derived from my general engineering knowledge, so any additional info or corrections are very welcom.
11-07-2006, 07:44 PM
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How much are you spending on the head gasket job?
$1300 for parts and labor?
So, when you're spending $1300 (or $300 for that matter) whats wrong with an extra $30-$50 for the peace of mind that new headbolts cost?
Sure, the Toyota tech's going to recommend reusing the head bolts if you're looking at the cost of OEM head bolts ($300 or so), but you can get headbolts that are just as good from engnbldr...
$1300 for parts and labor?
So, when you're spending $1300 (or $300 for that matter) whats wrong with an extra $30-$50 for the peace of mind that new headbolts cost?
Sure, the Toyota tech's going to recommend reusing the head bolts if you're looking at the cost of OEM head bolts ($300 or so), but you can get headbolts that are just as good from engnbldr...
