just wanted to put in something. i live in texas where the temperature soars to amazingly high temps! anyway i put a switch i bought from autozone and did the fan switch dealie with the stock sensor down by the passenger side front of the motor. i love it. now i can turn it on in traffic or at the drive thru! auto cool baby. ive never had a problem with my car overheating its weird maybe im just lucky. i just didnt think the stock fans coming on at 220 was a good idea. another ??? when does engine go into open loop?? i think its called when your cars done heating up?

 

I love having a switch to manually turn the fans on, too. It never hurts to have that option.

Your car goes into closed loop when you car reachs certain predetermined parameters are met. Your car goes into open loop when the car is first started, and then closed loop operation once the car heats up and certain other things happen. One of the parameters (if I remember correctly) is that the coolant temp has to be above 160* for the vehicle to go into closed loop, I can't remember the other ones right now. Once your car goes into closed loop, it should stay in closed loop.

 

Dont you mean open loop, cuz I thougth in the closed loop the coolant is circulated through the engine, in open loop the coolant is sent to the radiator and back through the water pump into the engine!!! I could get the terms messed up, but thats what the "how stuff works.co" said about cooling systems. Now, I heard people say that our cars go to open loop at 160, but thats not totally true since we dont have any restrictors on our thermostats. ( I could be wrong again, but I am trying to figure it out) So, I guess from my reasoning the CPU goes to open loop at 160 (much better car response than anything lower) and, depending of your thermostat, it goes into open loop when thermo opens!!. Now I found a problem in the cooling system. Most of our cars allow some air into the system, and air being lighter than the water raises up and it does collect right under the thermostat. Air is not such a good heat conductor, although it does conduct it, and instead of your thermo opening up at 180 it opens up at 220 when that air reaches the 180temp. If you think about it, a little restrictor to let that air out during closed loop is what our cars need. A little hole in the thermo always does the job. In the winter however, due to the nature of our cars and their poor heating up ability a normal 180 thermo should do the magic since it does heat up the engine to 190-200!!
Also, if you ever get a chance to drill a little hole and test it you will notice that the temp will not raise up to 220 and than drop. It will go to its designated temp and than stay there!!! Check it, its amazing. I think that the little hole along with a good cooling system is the key to keeping these cars cool!! You can tune your prom and get it to run at 180, but if it has air in the system its a problem!!!
I think I am making some kind of sense here, let me know!!
I've replaced the whole cooling system became a pro at backflushing and I tried everything, so this is what am seeing.
Now the fan switch you are talking about really does help, but dont turn it on early either cuz, unless you are just sitting, it will limit somewhat the airflow that could be coming in without the fan in its way!!!
Once again let me know if I am hitting some points here!!

 

I understand what your saying, and pretty much everything you stated is true, I just think some of your terms are mixed up (I'm not claiming to be an expert, either, though). "Open loop" and "closed loop" refers to whether or not the computer uses input from the oxygen (O2) sensor. Open loop is when the computer runs on a preset program until the car heats up, because O2 sensors work better at higher temps. Closed loop is when the computer uses the O2 sensor as an input to alter certain things, like fuel delivery, air/fuel ratio, idle speed, etc. once the car heats up.

The thermostats in our cooling systems do open and close, but it's generally not referred as "open" or "closed" loop. The thermostat remains closed when the car is cold, so the car can heat up quickly, and then the thermostat opens at a certain temp (depending on what temp. you buy like 160, 180, or the stock 195), so the car can stay warm, but not overheat, of course.

So, basically, open and closed loop operation of the computer AND the opening and closing of the thermostat are related and work together (to heat the car up quickly so the car can operate as efficiently as possible), but they are different systems.

All of this is what I have come to understand over the years.

 

Ya, makes sense. I probably have them mixed, but I am sure you know what I mean.

Now, I have to recomend to all the guys that are having a problem with cooling system. If you temp is getting to 220 or higher and than drops down you should drill a very little hole on your thermo. Belive me it will not do that again!! It will go to its temp and stay there, just like the newer cars!! Also, if the hole is small you dont have to worry about not warming up, cuz it will and it will warm up as fast as if you did not have the hole! I tried many thermos and many different ways, only thing that has truly worked was that hole on the thermo. I highly recomend it!! Try it at least, if you are still skeptical!!

It works!