overheating problem, maybe some suggestions please?

I know its not a Honda or Acura, but maybe someone could give me some suggetions/help, all combustion engines work similar right, so please help...
my car cools itself fine, no problem, fan works perfect, all fluid levels are fine, new water pump, not losing any fluids, changed the thermostat 3 times currently using a fail safe 160 degree thermosate, flushed the radiator, made sure everythign is sucking and pulling fluid like it is suppose to, and nothing seems to work...from 0-45 mph it stays right at the midway point, the minute i stomp on the gas to either race or merge onto the freeway, or cruise down the freeway at 60+ mpg (which is a steady 2500-3k in 5th gear, i know its geared low) it goes to the 3/4 mark sometimes a little more than that, i turn the heater on and it goes down a little, but not to the midway point...i turn the heater off and it goes back up to 3/4 or hotter....
Think an allumium radiator may cure the problem for better cooling, or maybe a head gasket? I have not lost any power at all, but runs really hot on the freeway....since i work and live in a small town...i don't have to use the freeway but i like to go racing 2 or 3 nights a week, and it would be nice to be able to travel the freeway and race....
Thanks for your suggestion
if you have any question you can email me at [email protected] or post here i will check in periodically...
Again thank you for any help/suggestions

i think yout problem is that you drive a geo. if i recall correctly, those cars arent supposed to go over 45 anyways. j/k :D . i would say try switching the radiator out, even for one thats the same as stock. and aluminum one would work also, but i am guessing that would also be more expensive than getting a normal one. also make sure the little fins on the radiator are clean. a head gasket isnt going to do anything for you to cool the car down. the other thing you might try is cleaning the motor. if there is a bunch of crap all over it, it cant dissipate any heat on its own. good luck.

Here is a pic of my engine...not coated, just polished out by hand...

I'm not going to now <-----------Looks at signiture

maybe i should change that...you now its all fun and games...hehe...not hurt feelings?

Make sure that the gauge and temp sending unit are working properly before you waste your time with anything else. My '88 civic did the same thing when I first bought it, and the problem was that the temp gauge was failing. If you plotted gauge reading vs coolant temp, it would have looked something like this:

180 F Cold
181 F Warmer
182 F Warmed up
183 F Warmed up
184 F Normal
185 F Normal
186 F HOT
187 F Off the gauge
188 F... off the guage


If you have a service manual for the vehicle, it will likely give a chart showing sending unit resistance vs temperature. You can use a multimeter to see what the sending unit is telling the gauge. If the sending unit is saying "temp's fine" and the gauge is saying "too hot," then you know it's the gauge.

Here is what I have on the temp & voltage...

http://geocities.com/chipman_13/sensor-trbl-shoot.html#TA

"Noth'in like Induction..." ;)

-Ryan-

what percentage of coolant and water mixture did you put in the radiator?

My guess is you put coolant way more than water.

Coolant is not used to cool your engine, most people think putting more coolant in will make their car run cooler, this is not ture. It is a chemical used for "anti-freeze", so your radiator won't freeze up during the cold days.

Water is the real substance that doing most of the cooling for your engine.

Hint--it's summer right now, so how much water should you put in there?

Going to colder stat, putting on a different rad, ect... Is just trying to hide/mask the problem. Sooo, doing those things are really not solving the problem....

Have you tried a new rad cap...?

Might have it checked with a "sniffer", it should tell you if the head gasket is leaking...

"Noth'in like Induction..." ;)