If you mean take the car on the street, he CAN'T drive the car with just water in it. He lives in NY and they are having freezing weather. Why risk cracking the block.toyomoho said:Sounds like the mechanic put a leak sealant into the coolant. This stuff can cause headackes for the cooling system and the cars owners, I don't recommend it. You are doing the right thing by flushing the cooling system. Attempt to flush the block also. If you can't finsh in time before class, just run the car on plain water until you can get all the garbage out of it. Once clean, drain the system and fill with distilled water and coolant.