Yesterday I had my radiator upper/lower hose replaced and the shop put in the green stuff. This morning I used a flower watering pot and washed away some of the grainy-looking things near the water pump and powersteering resevoir area. Just in that location and not much water too. Today I was going to go pick up some M-B coolant, and what do I see? The dreaded CHECK ENGINE light. I drove around the block and then turned off engine. It was still there upon start-up.

The car has 104k and had a major tune-up at around 90k (this included an $$$ O2 sensor!). It can't go out that soon!

Questions:
1. So, is there any connection between this CE light and the rad. hose service?

2. Can I still drive the car with the CE light onwithout damage to the engine?

3. Is there a DIY way to turn off the light, assuming it's minor?

Thanks.

ps
Shop said it will change out the GREEN stuff free provided I bring my own coolant. I just need a gallon, right?