I was driving my FD on a beautiful day yesterday around 85 degrees and sunny. After an hour of driving with normal temps my coolant buzzer goes off and temps go off the guage on my autometer temp guage and the stock guage. I pulled over and let it cool down immediately! 1/2 hour later I drove the final 2 miles to my house and let it cool down again. I topped off the coolant level and drove it today for 3 miles and the temp goes off the charts again in 5 minutes!

I suspect my thermostat is stuck closed. What do you guys think? Do I need a new thermostat or could it be something else? The car runs perfectly otherwise.

 

maybe.

when you say top off the coolant. Did you notice that you lost alot of coolant?

Did you double check that nothing is stuck (like a plastic bag) in the front opening? Can you tell if both fans are coming on?

 

make sure that your radiator cap is working. If it sticks open, you will spit all your coolant out thru the overflow tank, and empty out your coolant. I had the same thing happen to me, highway driving and the temps went soaring along with the low coolant buzzer. I have a high milage engine and was thinking that the time had finally come and that my engine had finally died. Over the past few months I was having to add coolant and thought a coolant seal was failing, so when the buzzer went off and the temps skyrocketed, I thought the time had come. A few days later my frined told me to get a new radiator cap and see what happens. Well I did and I have not had to add any coolant since. I'm hoping that the cap was the problem and not my water seal.

 

Thanks guys.

7- nothing stuck in the radiator and fans are running great.

overkill- I replaced the radiator cap recently. I do have to add a little coolant every 3rd or 4th trip. Yes, it spit out the overflow when it overheated. My overflow is full so I think I have a leak in my air separation tank hose. During cool down it does not suck the coolant back from the overflow.

But that does not explain the skyrocketing temps after 2 miles.

Anyone know what the torque settings are for the T-stat housing? I would hate to strip them out upon re-install?