I don't recall that conversation with David specifically, but I
imagine that I advised him that the trouble with retorquing diesel
head bolts is that some of them often get very dirty, changing the
friction coefficient, and hence the relationship between the torque
reading and the actual clamping force. More friction would mean that
you had to apply more torque to get the same clamping force. If you
marked the position of the bolt on the head before loosening it, and
retightened the bolt to that same point or further, you at least
wouldn't be making the bolt looser when you were done.
The proper way to get an accurate retorque would be, after loosening
the pressure cap, removing each bolt, cleaning the threads with a die
and the holes with a tap, blowing out the hole, and relubricating the
threads before reinstalling the bolt to the correct final torque, and
moving on to the next one. Of course very high accuracy may not be
critical. I can't prove that it is. An additional advantage of
removing the bolts is that you can see if they are TTY or not by how
far up they are threaded. And if the first one is not, you might
want to order up a set before proceeding, and replace the old bolts
as you go. If they are, you can reuse them.
If the gasket is seeping coolant to the outside of the block by the
turbo you may beat the leak by just tightening a few bolts in the
lower rear corner of the head. Look for coolant stains down the side
of the block.
Generally I have found that if you have coolant loss over a period of
weeks or months, only gradually worsening, and it is overpressurizing
the coolant, that it is more likely a cracked head than a head
gasket, on the grounds that the gasket, once it begins to leak
combustion pressure, will fail completely fairly soon and cause
massive leakage, where a crack grows slowly.
Happy New Year to all
Brian Holm
At 02:47 PM 12/30/2007, am864u wrote:
>When I re-torqued earlier this year Brian Holm advised not to do
>it. It ended up being fine.
>Big concern for you with the later motor is if you have stretch
>bolts, Brian R and I have the
>earlier 4 cyl diesel without the stretch bolts. You cant reorque
>stretch bolts.
>Since I had already started, I continued with the best advice I
>could get, specifically
>completely removing each head bolt individually, cleaning them (I
>actually re-inserted the
>cleaned bolt to get more dirt out of the hole and cleaned them
>again). Then dip in motor
>oil and torque.
>
>I would be patient and wait for a couple more folks to chime in on this.
>
>best
>
>David Shuman
Brian Holm, Parts for Peugeots
at Peugeot Holm, since 1969
2120 Maple Hill
Plainfield, VT, 05667
802-454-7132, fax -1310
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