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The old partnumber was, 7518335. But now you can only get the newer one which is 5955794.
The head bolts is what brought me to this site almost two years ago.
I decided to try to install a new set of bolts in a 900 that I did a second headgasket job on. The first gasket failed after about 70K miles and I thought to make it "extra" good the second time.
Well, I got the new funky looking bolts from Saab and installed them.
When applying the second stage torque to the bolts, 80Nm (59 lbf ft) Three of the bolts started to give way before the torque limit was reached, I continued to turn the wrench for a little longer, but finally had to stop when I felt that it was getting easier and easier to turn.
When I got the bolts out, they had a radical waist line about where the head meets the block.
I ordered a new set thinking I got a bad batch, but it was the same. Several of them failed before the second stage was reached.
That's when I started to do some research. Surely the dealer hadn't heard about any changes in torque limits, and no one on the board at the time had any concrete answer.
It was with the help of Tom Townsend that I finally found out that infact, Saab had lowered the torque specs on the new bolts and also made it clear that NO ADDITIONAL oil is required on the bolts when new, because they are precoated with some Molybden grease on surface.
With me pre oiling the bolts in old fashioned way, I actually lowered the friction of the threads and bolthead to the point where the second stage torque was more than the bolt could take.
And now suddenly from 97 and up, you can read on the NG900 and 9-3,9-5 board about failing headgaskets or weeping gasket and retorque heads recommended by the dealers.
Hmm? I just wonder?????
I did do a test where I cleaned the new bolts and holes in engine with brake cleaner, and applied the old torque specs. It actually works and felt good. But as soon it was additional grease on the bolt, it failed almost 50% of the times.
So that's why I recommend to throw away the used "new style bolts" and get new ones Even though you can only get the new style, it must be better than an almost overstretched old bolt.
Or go to a junkyard and salvage some old style bolts and reuse them.
Which are much more stronger.
posted by 66.229.128...
, Sat, 7 Dec 2002 10:41:56
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