Mr. Wilson wrote:
Fair enough. I was referring to the cylinder head leaks. And I also have no problems with ARP head studs. Yes the OEM bolts are torque to yield. I'm sure there is a lot of money invested in R&D with any upgrade/performance part. Well aware of this. I have worked on these Liberty CRD engines since they were introduced to the American market in 2005. Yes I am a CDRJ technician. And I have also had quite a few heads off a CRD liberty in the last 10 years. Along with sprinters and cummins. And not one time have I had a problem with OEM head bolts. Now I'm sure there are better parts and designs. I'm not downing head studs. I have installed them. They work well. And head gasket thickness is relevant when doing a cylinder head job. You should always use the same thickness as the old one unless you are replacing a piston and liner. Then you will need to measure the liner height. Might be why people are having problems with coolant leaks after a cylinder head service. That's all I'm saying. I'm simply giving out the information that I've learned by the training chrysler has givin me and the experience I've had working on them.
If you're using the same procedure as the factory, perhaps since you are a human, and not a machine, you are applying more even torque to the head bolts (or am I mislead that the factory uses a machine to torque these heads?). But, if not, and you're only as good as the factory procedure, or the TTY bolts, then I think you will find that they will leak, just like the factory ones, it will just take the same 80-180k miles that the factory torqued heads have taken.
Some of the factory ones have lasted until roughly 200k or so, and maybe some never leak, so unless you've worked on large numbers of them, then you may never hear back about any failures, or maybe they haven't racked up the miles yet
Do you use the factory degrees method? I would think that if a guy figured a suitable ft/lbs of torque, that they might last a good deal longer than the factory, at least under light use anyhow. I'm very unconvinced that the factory procedure applies even torque. And then there's the crappy bolts.