Hello. I have checked with this board a time or two since late last summer on cooling system snafus I have had, and I may have dodged a major bullet with this one. I don't think I have suffered major engine damage yet.

Earlier I was told the coolant temperature gauge is not linear and will show the needle in the middle of the range unless extremely hot. I mentioned I had never heard the cooling fan come on and asked whether that was normal. I was advised it would normally only come on under heavy stress.

Today after shutting down, I heard a hissing. I popped the hood and noticed that I had no coolant in the reservoir, and that the floor had a sizeable pool, the driveway where I had idled for a couple minutes with the AC on had a nice puddle as well.

I tried to add distilled water to the reservoir just to get something in there, it went immediately into radiator via the bottom hose. It has probably added to the leakage which is going on now, coming from under the water pump, on the spark plug side of the engine, right next to the heater pipe. There is a 10mm nut right next to where the fast dripping is coming from. What has failed here? I had noticed a little bit of weeping around the water pump recently, and I know this means that the water pump may be going, but I did not expect such a failure as this, I only expected it to increase weeping until replacement.

Anyone ever been in this situation before? I have looked at the FAQs and they discuss the same area, but I thought I would pick the collective brains of the enthusiasts out there. Any chance the coolant was getting very hot (I didn't notice the gauge) and due to a faulty thermoswitch a seal or gasket blew?