Torque Specs for Thermostat Housing Nuts (5VZ-FE) - 14 Ft-lbs?

alphyn

alphyn

New member
****** RESULTS *****

14 ft-lbs appears to be the correct torque spec. However, thermostat bolts are very soft and do not have the tensile strength required to hold much more than 14 ft-lbs of torque and will easily snap in a designated spot allowing you to remove studs without removing the water pump. Studs will snap at less than 19 ft lbs. So, you are in danger of snapping them if you are using a 3/8" torque wrench, especially one made by Craftsman between the years of extremely shitty production and extremely shitty shitty production. Makes more sense to use a 1/4" torque wrench and convert to 168 inch-lbs.

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Looking for sanity check here!

I've busted 4 thermostat housing studs (3 new, 1 reused) trying to torque to 14 ft-lbs. I feel like the following scenarios are happening:

  1. 14 ft-lbs is not the correct torque spec.
  2. My Craftsman Torque Wrench is inaccurate and a complete POS.
  3. Toyota has changed spec on studs and 14 ft lbs is no longer the correct spec.
  4. A curse has been laid on me because I will be replacing my 4Runner with a manual transmission Bronco in 5-years and supernatural powers do exist.

No idea what's going on. Studs seem to be made out of a really soft steel so are prone to stretching indefinitely below 14 ft-lb reading on my torque wrench. Thankfully, Toyota planned for them snapping and set a break point outside the water pump housing so I didn't have to redo my timing belt and could remove them with a stud extractor.

Has anyone else had this prob or can provide guidance? I'm about to pick up new torque wrenches because my crappy Craftsmans are pissing me off for other reasons. Getting some shiny new ICON ones from HF today.
 
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Gonna take a stab and say something was wrong with the studs already in some way. 14 ft-lbs is nothing and the steel would already have to compromised to fail at such a low level of force. Something COULD be wrong with your wrench but this is what I'm leaning towards.
To that effect, why are you using a torque wrench for 14lb torque value? Just use your hands. That's like screwdriver level.
 
Yes, 14 ft lbs is correct.
If you're using a 1/2" torque wrench that might be the problem.
They're not as accurate at the low torque settings.

As Devbot suggested, by hand should work well for those.
 
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Devbot said:
Gonna take a stab and say something was wrong with the studs already in some way. 14 ft-lbs is nothing and the steel would already have to compromised to fail at such a low level of force. Something COULD be wrong with your wrench but this is what I'm leaning towards.
To that effect, why are you using a torque wrench for 14lb torque value? Just use your hands. That's like screwdriver level.
Click to expand...

Oh, you know. Pursuit of accuracy and trying to do things right :rofl:

I doubt it's the bolts and I'm leaning more towards my torque wrench being way off - I don't have a torque wrench calibrator to check. I agree, 14 ft-lbs isn't exactly a herculean amount of force and should be pretty straight forward. All bolts were new from Toyota and all broke at the same spot with approximately the same amount of force applied. One bolt? Sure, could be an outlier. Not with 3 new bolts, no way.

I'm also wondering if thermostat studs are designed for more stretch, acting more like a spring than as a firm clamp. Steel used is super soft. Maybe they're not able to hold past 25 ft-lbs and force I'm applying is (obviously) beyond their tensile strength. I've been seeing a lot of threads where people are breaking them off. That's why I was wondering if there was an updated torque value, too.
 
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alumarine said:
Yes, 14 ft lbs is correct.
If you're using a 1/2" torque wrench that might be the problem.
They're not as accurate at the low torque settings.

As Devbot suggested, by hand should work well for those.
Click to expand...

It's a 3/8" drive with 10-75lbs range. Sure, at the lower range there may not be the best accuracy. I'd still expect it to be within 40% of values (14 lbs +/- 6 lbs) but I wouldn't expect it to be so far off I'd start shearing bolts, or that bolt shear tolerances would be so close to torque specs mentioned.
 
Yeah 14 ft lbs is nothing. When I replaced my TStat I used the German Guden torque guidelines on the inlet. It was getting dark and I had a long drive home.
 
If in doubt always calculate yourself from the Nm value. The ft/lbs are wrong in a few places, like the alternator tensioner for example. I have 4 different size Tekton torque wrenches and use them all.
 
And remember to store the wrenches at lowest value and NEVER LOOSEN stuff with a torque wrench if you want it to stay accurate.
 
repo said:
And remember to store the wrenches at lowest value and NEVER LOOSEN stuff with a torque wrench if you want it to stay accurate.
Click to expand...

Yeah, I've always stored them untensioned and never used them as a breaker bar. I have enough breaker bars. I picked up these Craftsman's when quality was at their lowest. Sears was shutting down mall locations and I picked these up at fire sale prices. I never had a reason to believe they were inaccurate until now. I've seen some good reviews on ICONs at HF so am going to crack open the pocket book and pick up a 3/8" and 1/2". Needed a new 1/2" because I have to tighten up the axle nut to 174 ft-lbs and my 1/2" "who knows how accurate" torque wrench only goes to 150.
 
alphyn said:
Yeah, I've always stored them untensioned and never used them as a breaker bar. I have enough breaker bars. I picked up these Craftsman's when quality was at their lowest. Sears was shutting down mall locations and I picked these up at fire sale prices. I never had a reason to believe they were inaccurate until now. I've seen some good reviews on ICONs at HF so am going to crack open the pocket book and pick up a 3/8" and 1/2". Needed a new 1/2" because I have to tighten up the axle nut to 174 ft-lbs and my 1/2" "who knows how accurate" torque wrench only goes to 150.
Click to expand...

Yeah the jumbo wrench (250 ft/lb) I can only remember using on axle nuts and I think the steering rack. It's nice to have though. I have a 1/4" in/lb one too which I use a 3/8 adapter and convert low ft/lbs to in/lb for more accuracy. The higher grade HF stuff is supposed to be pretty good. I think it pretty much all comes from the same factories in Taiwan regardless of brand. Basically USA > Taiwan > China in order of quality. The Tekton ones are nice and pretty cheap and are accurate as far as I can tell. Craftsman is actually making an effort to get their crap together now after they got bought by whoever. I've been buying a few Taiwan made Craftsman things because Lowes is close by.
 
Another thing worth investing in is a proper metric thread chaser set. I got one the other day after years and using a tap and die set to clean threads and cringing the whole time. Only about $30 for a USA made set.
 
repo said:
Yeah the jumbo wrench (250 ft/lb) I can only remember using on axle nuts and I think the steering rack. It's nice to have though. I have a 1/4" in/lb one too which I use a 3/8 adapter and convert low ft/lbs to in/lb for more accuracy. The higher grade HF stuff is supposed to be pretty good. I think it pretty much all comes from the same factories in Taiwan regardless of brand. Basically USA > Taiwan > China in order of quality. The Tekton ones are nice and pretty cheap and are accurate as far as I can tell. Craftsman is actually making an effort to get their crap together now after they got bought by whoever. I've been buying a few Taiwan made Craftsman things because Lowes is close by.
Click to expand...

I saw a tear down of the Snapon and ICON jumbos. ICON came out ahead in terms of consistency and accuracy. Tear down showed slight differences in design, but manufacturing quality was quite high.

I have quite a few Tekton tools and have been impressed by quality. I'd honestly go with them if ICONs weren't as highly rated. Plus, fastest shipping is next Tuesday. Trying to get my wheels back on this weekend and am feeling impatient, ha. Craftsaman tools are looking a bit better for sure. I have a few blown out ratchets I need to see if I can still get lifetime warrantied. I haven't looked into it. My main 3/8" Craftsman ratchet died on during this latest wrenching foray.
 
repo said:
Another thing worth investing in is a proper metric thread chaser set. I got one the other day after years and using a tap and die set to clean threads and cringing the whole time. Only about $30 for a USA made set.
Click to expand...

Haha! Yeah, that's me. I have a tap and die set I use to clean threads. Nothing like gingerly rotating them back and forth, little by little as you feel the crunchiness. I'll look for a proper thread chaser set. Every bolt I take out from my 4Runner I clean up or replace regardless of where it came from. Either I drop it in rust dissolver or give it a quick pass through the appropriate die. Over the years I've just been too annoyed trying to stick janky bolts in janky holes. Better to spend a little bit more time cleaning them up than having to deal with problems later.
 
alphyn said:
I saw a tear down of the Snapon and ICON jumbos. ICON came out ahead in terms of consistency and accuracy. Tear down showed slight differences in design, but manufacturing quality was quite high.

I have quite a few Tekton tools and have been impressed by quality. I'd honestly go with them if ICONs weren't as highly rated. Plus, fastest shipping is next Tuesday. Trying to get my wheels back on this weekend and am feeling impatient, ha. Craftsaman tools are looking a bit better for sure. I have a few blown out ratchets I need to see if I can still get lifetime warrantied. I haven't looked into it. My main 3/8" Craftsman ratchet died on during this latest wrenching foray.
Click to expand...

Interesting, I'm going to have to go check out HF. Haven't been there in years but I still use some Pittsburg tools I got ages ago when my only vehicle was a quintessential poor guy Suzuki Esteem, which was an amazing beater car tbh. Their floor jacks are from the same supplier as Snap-on or something like that too. Between Menards, Northern Tool and HF I'm spoilt for choice here as a tool cheapskate :bounce:
 
I would definitely try using a 1/4 inch torque wrench if possible. Snugging it up and going by feel slowly would be better tbh.
 
repo said:
Interesting, I'm going to have to go check out HF. Haven't been there in years but I still use some Pittsburg tools I got ages ago when my only vehicle was a quintessential poor guy Suzuki Esteem, which was an amazing beater car tbh. Their floor jacks are from the same supplier as Snap-on or something like that too. Between Menards, Northern Tool and HF I'm spoilt for choice here as a tool cheapskate :bounce:
Click to expand...

Hey, I know you from somewhere...

20200408-saul-10.jpg


Just picked up both the 1/2" and 3/8" ICON torque wrenches at HF and was curious what the reading would be if I retested some other bolts I torqued to 14 ft-lbs with my Craftsman torque wrench. The 3/8" torque wrench is rated from 20-100 ft-lbs and clicked slightly after one of my test bolts rotated 10 degrees. So, I'll assume it was tightened to slightly less than 20 ft-lbs of torque. Very unscientific.

This means the thermostat studs have a tensile strength under 20 ft-lbs of torque and you're going to be busting studs all day long if you torque them more than 25% of recommended spec. Tensile strength isn't measured in ft-lbs of torque, but if someone wanted to do the math calculating stud diameter, thread incline and ft-lbs of torque applied you could come up with the proper yield strength calculation.

In other words, if you're using any torque wrench with a standard of error greater than 25% you are in serious danger of snapping thermostat studs. I believe @%1;mbtim uses a 1/4" torque wrench and converts ft-lbs to inch lbs in his timing belt vid, which would minimize margin of error. So, don't use a 3/8" shitty torque wrench like I did. Your repairs will be delayed and your wife will look at you funny as you stare into your engine bay as you curse at things that keep on breaking.
 
alphyn said:
In other words, if you're using any torque wrench with a standard of error greater than 25% you are in serious danger of snapping thermostat studs.
Click to expand...

if your torque wrench has an error of 25%, it deserves to be put out to pasture as a breaker bar. i can't put serious $$ into a really legendary torque wrench, so i got one off amazon, an eTORK. i tested it against the three other analog torque wrenches i have, and one digital, and interestingly even the HF one that i've had for 15 years that i had to rebuild after it cratered, were all within a couple pounds of each other at 83 ft-lbf. the eTORK arrives with an individual testing spec, both referential to the testing standard and the 'within %' spec for the unit.
 
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