I was driving to the store today and when I got back to my car from the store I noticed a puddle of coolant under my car. When I was driving the coolant buzzer didn't go off but when I checked my coolant level it was substationally gone. Is my engine toast?

 

How did you check the coolant level? If there was still some in the overflow then the buzzer wont go off. It wont go off until the radiator gets about an inch or so low. Did you notice the temp gauge over half?

 

Are you referring to the level of the coolant in the overflow bottle? If so, that is not necessarily a problem. You need to check the coolant level at the filler neck. If that is OK, then just locate and repair the leak and you should be good to go.

 

your water level sensor could be gone maybe that's why it didnt alert you you can get one from atkins or mazdatrix for around 30-40 bucks

 

What kind of RX-7 is it?

If it's an FD it's not a good thing for this to happen. As long as your coolant temp gauge stayed normal you have a chance of no damage.

 

Ok try topping off your coolant at the neck of the radiator. and then turn it on and let it run. Watch! look under in behind tubing and anywhere you can see.. then once you find out what is leaking try to see if its because a tube is loose or cracked or summing else. I had the same problem before. It isnt to hard to fix. you can do it yourself.

 

check the water pump if u havent changed it lately and your hoses migth be a tiny hole but when heats thats when it gushes