need help overheating true or fals

[Henry0313]

hey hows it going i have a 91 mr2 n/a
I took it to a mechanic it has been 2 weeks and he story is tht my fans are not turning at the temp there suppose to turn on.
He told me they turn on late after the temp original temp its suppose to turn on.
He told me he has to reprogram the computer dont know which one, but that he has to reprogram it for the computer could tell when the fans should turn on and stay on for the fans wont start at the temp when its over heating is this true or false

[MrSo0h0o]

i would check the thermostat to see if it is stuck open or closed.

[MR2Jedi]

Didn't you change your thermostat a little while back?
I think thats BS.. Theres a sensor that tells the the fans when to kick on. I think I would test that before I started paying someone to reprogram my ECU.

Though I had a '92 N/A , besides regular maintainance, I never did anything else to it. So I'm not all that familiar with it(plus I got rid of it in '95).

[Henry0313]

yea i did and the thermostat its ok

[TAZZX2]

Please correct me if I'm wrong but arn't the rad fans ran off a temp sensor switch at the rad (you unplug it and the fans run constant) So if they are turning on late wouldn't it be because the temp sensor is reading wrong and not problem in the comp... Maybee replacing that sensor would fix your prob.

If your reading hot and the fans arn't coming on double check that you don't have an air bubble in the cooling system. If air hits the temp sensor for the gauge it will shoot up but the coolant won't be that hot. Try rebleeding the system, grab a ir/laser thermometer and watch the temp with that untill the thermostat opens. With such a long cooling system it can take a while for the therm side to warm up to the point it opens. gl

[4DMR2t]

Just to start off, to reflash your ecu because of your radiator fans don't turn on is just ridiculous. I suggest never bringing your car to that establishment again.......

Now, there are a number of things that can cause your fans not to turn on....... And to completely diagnose the problem, we'd need more information from you.

First thing I'd do is unplug the temp. sensor at the radiator. When you unplug the sensor, the fans should run at high speed all the time (with the ignition on, of course). If the fans turn on, that's a pretty good indication your fan control circuit is functioning properly........

Try this and we'll go from there........