So just for my curiosity, let'* say the engine is warm and the coolant has cycled a bunch of times so it'* all cycled through the engine and is warm. if I'm driving on the highway, how many degrees cooler is the coolant that is cycled in than the coolant cycled out (195 degrees)? In other words, how far does the needle typically drop in an air free system?

Also, what temp are fans supposed to kick on?

I am not sure the exact temp, but I believe the temp gauge would bottom out around 190* to 195*, but I also believe the fans wait until about 215* to come on low and 225* for high. You can also turn the A/C on (assuming it works) and when the compressor is running, the fans should be on high was well. Not sure on the exact temps, as I am blessed with only an idiot light to tell me I just blew it up.

But wouldn't it be frustrating if that light didn't come on to tell you why you blew up??

Sounds like I still have a little air inside. Life has been worse. At least no removing parts or draining coolant for this fix. I'll have to check them out with AC on. Thermostat didn't open when system wasn't pressurized (first time, tight fit, probably a bit of silicon holding out also - had rad cap off to attempt to get air out). Temp hit like 200 and coolant came bubbling out real quick. Turned her off, waited, took for a drive and everything worked fine.

My temp gauge is still dropping to about halfway every time I hit 195 and the stat opens. I've let the thing run with the rad cap off for 20 minutes but the level never drops. I started squeezing the hoses towards the end of it too. I can't seem to find any air in the system. I opened the bleeder screw a few times also and coolant came out right away, no bubbles.

This has to be air right? The system heats up nice and quick. Sometimes it gets up to 200 or so before it opens, but it always does. What'* the best way to get the air out without taking the thermostat back out? I unfortunately did not fill up the manifold before dropping the new stat in, so I'm sure that'* the cause of the problems.

Usually, they recommend drilling a small hole in the thermostat to let air through even when it is closed, and if possible, try and bleed the system while the car is on a hill or ramps or something, so that the engine/radiator is the highest point. I noticed the behavior you described though in other cars, and attributed it to normal operation. The coolant in the engine heats up enough to trip the thermostat, then the thermostat opens, and flows all of the nice cold coolant that has been just sitting in the radiator, through the engine.

Yes, I've read about the hole drilling. I personally don't feel like this is the best solution because there is always coolant flowing through the thermostat now. I understand it'* a small amount, but if this were the solution they would manufacture the thermostat with a hole, right?

I may have to try raising the front of the car as you suggested. I don't think this is normal. I agree the needle will drop when it opens, but this is dropping 30-50 degrees if it is reading correctly. It heats back up quickly, cycles again, same thing. I drive thirty minutes each way to work so I would be surprised if there was any coolant at 150 after a half hour on the road under normal operation. Maybe I'm just used to my car operating with the old thermostat and this seems odd because it'* different

I pressure tested system and found a leak at a heater hose, could this have been sucking in air out causing this problem some other way?