This has been a nightmare for me. I have a 2000 S4 Automatic. Everything was running fine until I decided to change the spark plug. Because it was dark, for a moment I thought I saw something fell in the spark plug hole cylinder 1 (front driver side) but I thought it was nothing.

I ran the car and it was fine for about 5 minutes, then it start rattling, thumping, and other weird noises occurred. The car has loss of power until 5,000 rpm but it got hot fast. I finally did a compression test after it was in storage for 2 weeks. It appears to have 0 PSI in cylinder 1 (front driver side) and the rest of cylinder 2,3,4,5, and 6 has 175-182 PSI.

I was told that the engine may not be worth rebuilding because it may need to be x-ray for any cracks.

Does anyone have any ideas if this engine could already be shot and not worth rebuilding?

I found an engine for $1,550 with 60 days warranty. It's a long block less the turbo's, alternator, starter, and A/C compressor.

Rebuild or Replace, which is probably wiser to go?

 

ouch.... sorry to hear that.... if your mechanically meclined i would recomend taking off the cylinder head with the 0 compression and take a look at the piston and piston walls... the stock pistons are forged and may have made it through the battle... the valves on the other hand are soft and bend easily when something gets in there(or piston hits them from broken belt...) so take the head off and take the head to a machine shop to have the bent valves replaced.... probably cost you 500 or less for evertything including all new gaskets... i'd say it's worth rebuilding most likely... if you've got a hole in the piston that's gonna take a bit more work and a new used engine with warranty would sound pretty good.... GOOD LUCK!