I tried Thermogasket as a last ditch effort to save my 1990 Dodge Spirit from the scrap yard. The symptom was that the temp gauge was reading at the high end of the range, even though the engine was not that hot. A tune up shop confirmed the presence of exhaust in the coolant.
I tried Thermogasket, using their "freezing tempurature" procedure. This involves making three 50 mile trips with an hour in between in a single day, as opposed to keeping it in the car for 400 miles. This is supposed to cure the repair. I would have had to wait until spring to the 400 mile route.
Anyway, at first it looked like it was working. The gauge dropped to the middle of the normal range. I took it on the three 50 mile mile trips. On the interstate, the gauge read only to the first line in the range. I thought that my problems were over.
I came home, flushed the system with water as advised, and re-filled with the anti-freeze/water mixture. I even replaced the thermostat, as it took some time to open during the start of the third trip. I then took it on a test drive. As soon as I did, the gauge moved to the far end of the normal range, just like it did before.
They claim to have a 92% success rate. It is almost like the anti- freeze disolved the repair that was in place. They have a money back guarantee, which it looks like I will be using.
Any opinions welcome.
Thanks,
Kirk Matheson