Coolant Problems

My 97 TC began leaking coolant. Symptoms were that of a bad heater core, with steam and coolant leaking on passenger side, but in the engine compartment, not in the cabin itself. I did however have the smell of radiator fluid coming in thru the vents, along with the initial "cloud" that told me it was probably the heater core. I put in a bottle of Bar's Stop-Leak, topped off the overflow and proceeded to run the car for 45 mins. The smell went away, temp. in car is fine, heater works just great (set controls for 90 degrees and it got nice and hot inside). Everything appeared to be working fine. No leaks observed, nothing to indicate that there was a problem. When I stopped the car and let it cool off, I noticed that the overflow tank was empty. I refilled the overflow tank with coolant and ran the car again for another 45 mins. this time idling it in the driveway. Lo and behold, the overflow tank was again empty. I'm now wondering: where's the coolant going to? I do not appear to have any leaks in the system; inside the car is bone dry, nothing leaking onto the driveway. I'm stumped. Any ideas?

Tks

JP

Forgot to mention: I also checked the oil to see if there was any infiltration ("milky-like appearance) and the oil appears to be fine as well.

You neglected to mention whether or not you actually checked the coolant level in the radiator?

After such a problem, you fill the radiator first, then the overflow tank.

With the information you've given so far, my guess is the overflow tank is trying to fill the radiator....

You hit it on the head. I needed to get the radiator full. The '97 appears to have a sealed radiator, so the only place to fill it is via the overflow tank. It took a few "refills", but it is now sealed. Thanks.