Retorque cylinder head bolts

[Peter Orban]

Interesting talk about head bolts, we are doing a head gasket on my son's car, a 91 Golf.

The Bentley manual for the Mk2 Golf/Jetta, like the one quoted here for the Audi, mentions that one can reuse the head bolts. (Same part number for a '87 4kq and '91 Golf head bolt.)

If the torquing process means stretching the bolts to the yield point why would VW/Audi ever suggest not to replace the head bolts? 
BTW, VW/Audi never mentioned that those are stretch bolts...

Thanks, Peter

--- On Fri, 10/15/10, quattro-request at audifans.com <quattro-request at audifans.com> wrote:
...
To add to the confusion, in the Bentley book there is some notes, page 15.13
:
 
Caution : do not retorque cylinder head bolts at first service or again
after repairs.
Note : It is not necessary to replace polygon head bolts when making engine
repairs. Bolts can be reused. However, new bolts are to be used in sets
only.
 
So, maybe the holes in the block were not clean enough to keep the clamping
force ? However, the block was cleaned in a caustic tank and prepped by a
reputable shop. More, we installed the head and all exhaust plumbing on the
engine while it was in my shop. We then installed the complete drivetrain
from under the car in a single step.
 
Any ideas to prevent this loosening to happen on the upcoming rebuilt ? I'm
a bit tired of pulling the head on this car, since it is such a big task to
do it in situ with all the plumbing attached to it. 
 
Louis-Alain