I have a 2001 Pontiac it over heated while I was driving it and I pulled over and put some water in it. It won't start back. It cranks and spews coolant back out.
Engine damage is already done, have ti towed to a shop of your choice to confirm head gaskets or a head problem. This job can be performed by an independent shop so you don't need to spend money on dealer prices to have it fixed, but it still won't be cheap.
Putting water into an overheated and still hot car can destroy the engine. You have probably warped a head or cracked the engine block. I would junk the car as it is old, but not a classic or a car of great value.
Another alternative is putting in another engine, new, rebuilt, or even used.
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