I would also add the goop to a hot, running engine, to make sure it gets distributed as well as possible. Dumping it into a cold, still header tank is probably less than ideal. Pre-mixing with coolant would also seem to me a good idea.
Regards,
Ray L.
More informed people than myself may disagree but this sounds like a “stretch”-pun intended. For one thing the nut would have to not yield (turn) before the breaking point of the stud.
IMO it depends on if Andy’s 1969 Series II has the long stud or short stud engine. If long stud then there is certainly the possibility of corrosion of the studs in the water jacket reducing the strength of the studs. If one of the older short stud engines not so much of a worry.
Have you seen what happens to the studs in an XK engine after many years, particularly if coolant is not well maintained? Some are reduced to less than 1/4" diameter, making the VERY easy to break.
Regards,
Ray L.
I have seen some terrifying pictures but, to snap one means that it would only withstand less than the torque applied to stud nut which, I haven’t looked but, must be between 40 60 lbs as a WAG. The nut doesn’t get corroded to the threads, does it?
and if it’s going to snap at 60 lbs, isn’t it likely to fail all by itself, imminently?
I can understand snapping a stud when it is galvanic stuck in the water jacket and you are using a lot more than 60 pounds to try to unwind it.
Probably true but the way I see it is, better to let it fail by itself than advise someone to torque without them knowing the risks.
The head bolts are, IIRC, 1/2", which gives them a recommended torque in the 41-57 ft-lb range. A 1/4" bolt, OTOH, would have a recommended torque only in the 6-7 ft-lb range. The tension load on a head bolt is very nearly constant, with only a small cyclic load due to the engine running forces. Even a badly corroded bolt will still have considerable ability to maintain tension but will be much more susceptible to failure when torqued. So, it might hold just fine if left alone, but fail the instant you try to twist it. I think anyone who has removed the head from an old, poorly maintained XK can vouch for this - they will often find several head bolts shear off as soon as they attempt to loosen them.
Regards,
Ray L.
Are you sure the leak is from the cylinder head and not from the intake manifold??
Dennis 60 OTS
Thanks to everyone for your advice. Prior to posting I did re-torque the cylinder head to 58 ft lbs in the correct sequence without incident. (My car is an early S2 VIN 1R25536, Eng 7R3247-9). Is this short or long studs?
Ray L, I’m leanig toward Prestone because I use their antifreeze. Do you have a part # for the Prestone Super Stop Leak or photo of the container? There are lots of different products on the market and I’m somewhat confused.
Thanks Andy
Oddly, they now seem to have several stop-leak products, for different functions:
I have no experience with any of these, but I would trust Prestone, and just pick the most appropriate for the problem I’m trying to solve.
I’m sure any of the Barr’s products are fine as well.
Regards,
Ray L.