I had a 93 900S years ago. Great car. One of the quirks of owning a Saab is the diligence required in maintenance. If you check your owners manual it will state that the coolant needs to be replaced annually. I don,t remember the coolant required but do not deviate from the manufactures recommendation. Those motors have a lot of different alloy parts in the water side and no one coolant can protect them all, so Saab says to replace the coolant annually in order to keep the corrosion inhibitors working.
Now, back to the problem. I too had a head leak. I discovered it on a Wednesday but couldn't doing anything about it until Friday. I put some of that stop leak crap in for the mean time and it worked! Friday night comes around and I roll into the garage and wait for the motor to cool. A few hours later I had the head off and slung under my arm walking down to the machine shop around the corner. The head had a small warp in it (it happens easily with a blown head gasket, so take care) and the shop milled the head flat taking .008".
The next morning I picked up the head and a new gasket and put it all back together. I reused the head bolts. After reassembly the cold cranking compression was within a PSI of all cylinders (before disassembly the number 3 cylinder was lower by 15 PSI).
Back on the road that car was super spunky. The slight mill work gave it a small bump in compression and it showed. That car was a blast to drive again. However, when winter came around, My heater core was plugged up with what I suspect was that stop lead crap.
And unfortunately, changing a heater core on a Saab 900 is a bigger pain in the ass than pulling the head.
Just some food for thought,
Skippy
