Poston 160 Thermostat



Just ordered a Poston Enterprises 160 thermostat, it came in a A/C Delco Box. I called GM Dealer and they had no listing of the part #. Installed it hoping it was a 160 anyway, but the damn thing is still running at 180. I have the poston chip which is suppose to turn on the fan at 170 and the fan never shuts off cause it wont stay under 180. :confused: Note the chip is suppose to be for a 160.

Ps.- I ordered the thrasher chip.
If you still have the original radiator in your car, it is probably pretty plugged up with crap...A 160* thermostat isn't going to help if the rad. won't cool properly...
It should of been stamped 160 on the termo. And just because the thermo is 160 does not mean warmed up it is going to stay there at all. Even on cold nights my car will not go lower than 167.
Now if you have an aluminum radiator we have a different scenario.

What are you reading the temperature with? (scan tool, mechanical gauge?)

And the 170 fan turn on is really to low, the 185 is plenty. As your seeing it will be running at every light and idle, and only turn off when you get over 35. So I would get a different setting so that your fan lasts the summer or atleast 5,000 miles.

Now, when you start the car, do you notice a temp drop around the 160 mark? Usually they will go over the temp alittle like 4 or 6 degrees, but you should see a noticeable drop in temp due to the cold sitting water. Then you can see the termo opening around the 160 mark and know its not your termo, but most likely your radiator.
Yeah i figure it was the rad, what should I do flush it like 20 times, I checked it with the scantool, it stays around 170 usually, and it wasnt stamped on the bottom of it. HAw can I change the fan setting if the chip controls it, I am changing to the thrasher anyway, do you know when the fan kicks on with that chip???? thanks so much
You should try a good flushing, but most likely there is just alot of sediment on the bottom of the radiator from the water and age. So the next step after the flushing is to get it recored for around $120.

But if the scan tool is around 170 cruising, that is good. For now I would just flush and specify the fan setting in the chip when you order it.