Why bother disconnecting the fan at all - it is an electric fan and should only turn on when it needs it like at that long light. You only have 1 gallon of coolent in that engine too so it can heat up pretty fast and needs to be properly cooled plus the plastic radiator may have problems if you get it too hot too often.
With mileage that low I would be looking at a new exhaust from autozone and checking the MAP sensor hoses - there was a recall that added a bleeder to the MAP sensor - they basically added a T fitting to the hose between the MAP sensor and the intake manifold and let some air flow through an orifice to prevent moisture from collecting and freezing in the lines in colder weather. Make the hole in the orifice smaller - it's a pin hole in a plastic coupling along the firewall running towards the center of the car and the MAP sensor is in front of the heater high up on the firewall.
Getting hot like that isn't going to help you at all no matter what, but even worse if you are OBD 2 because once you go above a certain temp the ECU goes into a 'limp' type mode where it pulls ignition timing and enriches the fuel mixture the help the engine run cooler.
If you do run a hotter thermostat consider running a higher pressure rad cap too. If your car is anything like mine it's on the edge all the time when it's at full operating temp, and that's because I have a 16psi cap.
Trying to run hotter because you guys said its good for FE and I believe you guys =). I want to hit 40 mpg, I been close a few times.
I disconnected the fan and it was doing great on my regular commute to work. My job is mostly freeway then 3 stop lights. Temp went a little higher then normal but nothing scary. So I was thinking of taking it off compeletly to save some weight since my Metro is like 55 horsepower and I got rid of a good 80 pounds already.
Anyway, today I was just running some errands and it was 80 degrees. Things were looking normal even stop light to stop light until I hit a long light. Then it got this hot.
Is that too hot? Im having second thoughts about ditching the fan now.
When I got on the freeway the temperature went down to normal in under a minute. When I dont get lights more then 1 minute long its not too much hotter.
I do have a WRX style scoop in the mail and Im going to make it functional so once I have that in I'll see if it lets enough heat out in heavy traffic. If not then I guess the fan has to stay.
Derailing my own topic for a second. I've seen big improvement in MPG replacing the distributor cap,spark plug wires and spark plugs. I think everything on this car is original and I was wondering how much my o2 sensor,fuel filter and pcv valve is holding me back. Also if you have a metro where the heck is the PCV valve and fuel filter?
I wouldn't get rid of the fan completely. My cooling fan quit working as it should, it no longer cycled on and off when it should have. I just wired it to a toggle switch on the inside of the car and the only time I ever have to turn it on is when stopped for something like a red light on hot day. Be sure to put an inline fuse in the circuit. This will keep your temperature up and also give you cooling when needed.
One of my fan sensors doesn't work right (I replaced two of 'em) and the fan won't shut off, so I disconnected it last summer. It's overheated about 3 times (learning curve) at lights or in rush hour Atlanta, but no damage because we got off or got going. I was thinking of the switch and a stern lecture to the wife!
$1000.00 in parts can save you HUNDREDS in gas!
Why didn't you just turn on the heater on full blast?
I just changed radiators on Wagonstein a week ago. The radiator that was in it was designed for a 2.0L 4 cylinder. The car has a 3.2L cammed and turbocharged V6!! In rush hour traffic, with the cooling fan running constantly, engine temps would climb. When it would hit about 225 degrees I'd turn the heater on full blast and I could watch engine temps drop down back to a normal 210 degrees.
Now I've got a larger dual core/dual pass aluminum radiator. The cooling fan rarely comes on now unless stuck in traffic at long traffic lights, and even then it no longer runs constantly. Maximum engine temps are now also down to 201 degrees.
So maybe if you installed a much larger radiator with a VERY small fan. Have that fan conneted to an automatic switch set to say 220 degrees. But, also have it connected to a manual switch in the cabin so you can turn it on if you know you are about to be stuck in traffic, or idling for long periods of time. And as a last resort, you can turn on your heater to remove heat from the engine.