Hey gang-

This weekend I installed a thermostat for the first time (on a 1996 F150), as preventative medicine, as I have 96,000 miles on it and this is the first or second thermostat (I can't remember). I used a Stant. It seemed to go well. I did notice different dashboard gauge results, though. On my previous thermostat, once the truck was warmed up, the temp gauge tended to stay exactly at the halfway point all during driving, regardless of the season, whether A/C on, et cetera. With the new thermostat, once the truck warms up, the temp gauge it will hit at almost the half point and then regularly go down to the 1/3 point and bck up to the halfway. I read that air in the cooling system can cause lower readings (i.e. the temp sensor/sender reads cooler if no coolant on th sender)

Q1: Stants are good, yes?

Q2: Is it normal for a given model to have a characteristic, ideal temp gauge reading (i.e. halfway on mine with a normally functioning system, original thermostat) ?

Q3: Is the fluctuation normal?

Q4: How can I properly purge any air in the coolant? Run engine with the reservoir tank open to "burp" it? Run engine with the radiator cap off?

 

I changed my therostat a couple months ago in a 97 4.2 V6. I put a 180, I think, and the temp is doing what it did before. Normal. I squeezed the top hose to help get the air out. I'd say let it go awhile to make sure all the air gets out and see what is happening. It could also be the cooler fluid going past after the therostat opens? Good luck.

 

Get the air out by filling it up, as you did, warm it up good, and then let it completely cool down, let it set overnight if possible. Then the next day open it up and it will probably take another little bit of coolant.
I work at a shop and what I do on coolant flushes (not enough time to do what I described above) is fill it up and start it without the cap on, fill it up once more when the water pump sucks in what it can with the stat closed. I cap it off and let it warm up then shut it off and feel the cap, if it is hot then there is pressurized coolant touching the cap, if it is cool(which it normally is) pull off the cap and top it off. There will be no more air in the system this way. Don't forget to fill up the reservoir.
I have never had a problem with a thermostat, from expensive to stants, there all ok as long as they are the right temp setting.

 

I spoke with my mechanic recently when we decided to flush the coolant system. He wanted to make sure that I did not touch the thermostat, due to the fact that our computers are dependant on the factory settings. The computer will not regulate for after market thermostats... I don't know what ford says about thermostat replacment, but make sure your computer is interpriting accurate reads.


Can anyone elaborate on this further???

 

thanks all