Thanks. I just pulled the belt,same result. Turned the key starter engaged but couldn't turn over the engine. When this happened I did not notice any warning lights on oil pressure normal,temp. normal,no over rev,no high speed. Just a short trip maybe 1 mile, barely warm.Do you know of unusual engine seizing? Only 115,600 miles. I'll try to turn the crank today before I pull the starter.I must say the starter got some abuse when I had the problem with the fuel pumps and the water temp. sensors. I had to crank the car to the point of needing a jump and then recharge the battery a number of times. The starter kind of sounds like it might have a "flat spot". As always, thanks for your help.I'll let you know of any progress.It's really frustrating cause I like this car.

 

To update this file. The engine would not turn over,the starter would engage and try to turn but couldn't.(new battery) So I pulled the plugs and tried to crank it over,no luck. Put a wrench on the crankshaft nut and tried to turn over the motor,no luck. I tried to turn in both directions ,no luck.I only had a 14" breaker bar with no extension. As a last attempt I tried the starter again. First and second tries the same,it engaged but wouldn't turn.ONn the third time it turned over freely. Tried again,turned over again. So,put the plugs back in and it fired right up. Sounds good right? WRONG. Now I have a loud knock that came out of no where. Piston,bent valve ? Don't know yet. The engine was frozen what could it be????? That's the big question before I surrender and take it to a mechanic.
At this time I must give credit to "chassis221"for his excellent assistance.He correctly diagnosed my fuel problems, I replaced the temp. control sensor and it fired right up.He suggested (and I hope he's right),that a car of my vintage might have dropped some carbon and that's causing the noise. His suggestion was a quality fuel cleaner,which I've done. Now it's wait and see. Any other thoughts or experiences ?????

 

I have the same problem with my 1997 SL500. Battery is dead in 1 to 2 days. Does anyone have any similiar problems? Any solutions of where to begin? Seems like something is draining the battery pretty quickly.