I remember this one well. The party was resting with the gnomes during S4 and needed help with some clay golem damage. The DM put a 17th level scroll of healing with the gnomes to solve the problem (I don't think it was originally there). The gnomes were not going to turn over the scroll for free, so we were off to hunt some norkers.
We got totally hosed at the temple. Several characters were down to single digits and we all loved that our party was rich in fireballing magic-users (as they were called in the day). I think we had an elf fighter/magic-user, a dual class cleric/magic-users, and a pure magic-user.
We fell back from our initial asualt and took a week to heal up. Yes, a week. We were pretty badly damaged and cleric light. In addition, a few new characters we rolled up. including a dwarven thief.
When made our second assualt during another session, the DM had taken all the appropriate monsters from under the temple plus a bunch of recruits from the mountain giant and turned the first room of the temple into a blood bath. We barely won that one and had to retreat again. The new dwarven thief was not so lucky, now replaced with a gnome cleric/illusionist.
Third time was a charm against the humanoids and we finally broke into the lower temple. There we found a bunch of stuff we didn't know what to do with as well as a horrible shadow demon that possessed our cleric and then our ranger. Most of the party died in the confusion, including the gnome cleric/illusionist.
The few survivors limped back to the gnomes. Another week or so went by, and the party boosted its ranks with a few more gnomes (ie, new PCs). This time we killed the shadow demon, retrieved the bodies of those we wanted to raise from the dead, and called it good and proceeded back to the caverns of S4.
A very good time. We missed a lot of the stuff in the temple because we were too busy dying, but I think the ranger got a 19 Con out of the deal (great for 1e). Of course he then died and was raised, so he ended up at even, and he was the one healed of the golem damage. The rest of us ended up universally worse off. Worst side-trek ever (from the characters point of view).
The entire party would retire shortly after finishing S4, due mainly to too much character turn over started by the Forgotten Temple.