It is possible with some types of torque wrenches themselves, however the torque required to undo something isn't necessarily the same as the torque that was required to tighten it. If the bolt for example was greased before tightening and then left allowing the grease to dry out it could make a huge difference. Slightly random fact here, when the molybdenum disulfide and copper slip greases came into use on ships (long before my time) there were issues with tie bolts failing regularly on diesel alternators due to the torque readings being given for "dry" threads and surfaces and engineers slapping the new grease on to aid in disassembly. The torque readings were right but the bolts were overtightened causing premature failure.
In my professional experience when equipment must be assembled to a prescribed torque and initially assemble did not record the torque, they loosen off and tighten the bolts/nuts/fittings and recorded torques. On the small projects I've been involved with this can mean a weeks of work. Given the time and expense of this I a guessing there is not a way to accurately measure the torque of an already seated nut/screw/fitting.
I was more thinking of investigating a failure as opposed to assembly torquing of bolts, screws e.t.c. certainly backing off and re tightening with a calibrated wrench is what I'm used to.
As previously mentioned, loosening a screw or bolt requires far mess torque than tightening it to a specific one. So the only way to know would be to loosen and retighten. Iness you need the tube fittings? They're usually just hand tightened, although the EK ones I have have a allen key in the mddle to aid tightening, so you could torue wrench them.
Could be either, if machine assembled the driver will be set to a torque value but the accuracy would be up for question and if hand assembled it depends on the person assembling the item. It's surprising how many people over tighten even when using a correctly set torque wrench (the lower the setting the easier it is to over torque something especially with the clicky wrenches). As Bloody_Pete mentioned a leak test would be a better option as it's not just torque values that could cause a leak, damaged seals, damaged threads, cracked components and even misshaped parts could be responsible.
Back to your first post, these leaking block is it from the fitting or the block assembly? To muddy the waters a little further, this article from Parker seems to imply that a static o-rings provides best duration performance when highly compressed, provided they can be installed with out pinching or other physical damage issues. This is contrary to my understanding, but that might be more due to my teachings being based on dynamic o-rings (for example within a tap).
I guess it's like anything else: they could lead due to a wide variety of reasons, which are so innumerable that you'd drive yourself round the bend worrying about all of them. If you do a leak test then you'll know if your block leaks or not, and that's about as certain as you're going to get really.
Likely no. But you could always ask the manufacturer for their test procedure. If they have a good procedure they should be happy to let you know as it is good PR. Is each unit individually tested vs spot checking 1 out every x units? I have not bought a water block in a while, but the last one I bought was individually pressure tested to 80 PSI or some such number, well above operational conditions. Bonus marks to anyone who can name the brand. bawjaws has the best advice. And if you are really paranoid, repeat the leak test as part of the annual maintenance.
