Trouble after new water pump and t-stat

2002 C2 Getting home the other day, I noticed a horrific screeching sound which i found to be grinding and shaving of metal between the water pump pulley and the motor mount bracket. Old pump was hard to get out as the pulley was sticking out about half an inch farther than normal and touching the mount bracket. I did a lot of raising and lowering of engine (on floor jack) and used a pry bar to really push the motor mount as far as I could to finally wedge it out. Old thermostat came out with no problems. The thermostat wasn't showing any issues, just replacing it since i was there. Installed new water pump and low temp thermostat. After pouring a gallon and a half of coolant into the overflow tank, I realized that it wasn't diluted. I'm not sure how bad this is, but I just added a gallon of water to the system (I emptied about 2 1/4). One more admission; while i was trying to figure out a way to get old pump out, I removed the lower idler pulley and, even though it didn't feel/sound bad, I removed the bearing covers and packed them with some grease. Afterward, it didnt turn as freely, but I figured it would be ok and work itself out. When I went to start the engine, there was a loud screeching noise similar to the original water pump pulley sound and the engine did some major sputtering. I tried pushing on the accelerator and it made no difference to the sputtering. I took off the airbox and could not see any issues along the belt and pulleys. It has been raining outside and the car has been sitting for about 6 days while I waited on parts. I let the car sit while I ate dinner and came back to try again. I left airbox off, but kept maf connected and started engine again. This time, short screech and small stutter and then somewhat regular idle (every few minutes there might be a quick jump in idle that only lasted half a second). I noticed that coolant level light was flashing and there was no temp reading, but then saw the message for temperature indicator failure. I was worried new thermostat wasnt working, but after the engine warmed up I saw the coolant level go down in the overflow tank (that's when I added the water). Am I right in thinking that means the thermostat was opening up? I'm considering the screeching sound to be a lubrication problem in a pulley due to the long sit in the rain...did I mess up the idler pulley with the grease? While the engine was idling, I did notice the tensioner pulley was vibrating a lot (about 2mm), but I wasnt sure if that is normal or not. I wasn't sure where the coolant temperature sensor was, but now have a good idea and will look at it in the morning. Any ideas on what else could be causing the failure indicator with the temp gauge not moving at all?

How did you bleed the system?

First remove the belt and see if it sputters and screeches. If not, replace the pulley and check all your work. There is no reason the engine should sputter after that so you may have forgotten to plug something in or alternatively pulled something loose when raising and lowering the engine.

Quotes source post: 14503246

I didn't totally bleed the system, but drained fluid from the drain plug in addition to what came out of the hoses going to the pump and thermostat. I replaced the fluid when i put in a new overflow tank a few months ago, so didn't think a full bleed was necessary. Going back out now to look for anything disconnected and try without belt.

So, went out this morning and started engine after removing belt. No squeal. No sputtering. Started again after putting belt back on...no squeal and no sputtering. Maybe things were just sticking after sitting for a week in the rain? Looked over the temp sensor and felt for any movement or looseness. Nothing wrong with it that I can feel or see, but temp gauge is still not working and light is still flashing. Going to replace the sensor, just in case. After idling a bit, the coolant level went down and i added more water. Assuming thermostat and water pump are working normally, but not going to drive it until I know I'm getting a good reading on the gauge.

There have been cases of people using the wrong pump assembly with the 996 - I think it's the 997 pump - where it appears to fit fine, but in fact the impeller contacts the block when the pump is fully installed. Maybe this isn't the case here, but I'd double-check the part #...