I have Corvette c6 standard 2009 .When I am driving my car fast like 100kmph or above coolent temperature stays normal around 90°C and if i stop over or drive slow at i.e 50kmph or leave my car idle while engine is on then the coolent temperature goes above 125°C over heating messages will come to dashboard and water boils out from reservoir..
please tell me how can I fix this issue

 

 

I agree, check the fan operation. It might also be a burnt wiring connector which apparently is common. Do not allow your engine to overheat as that's a quick way to rack up some big expenses

 

How to check the raditor fan.

Start the car cold with the A/C off, and the radiator fan should not be running.

Now turn the A/C on, and this should turn the fan on.
Hence AC heat exchanger coil is in front of the radiator, and the fan comes on to draw air through the heat exchange coils, even when the car is idling/sitting still.

If the fan does not come on, then check the radiator fan connector on the passenger side, back of the radiator. Hence most of the time, this connector is the problem when it pulls a "three mile island melt down" from someone turning the fan on more with a retune.

Red dot is on the connector,
Attachment 48334002


And unplug it to make sure that the connector is clean, and not burnt up.



If the connector is melted to hell, then with the motor off, reach so you can touch the fan, and spin it by hand. If the fan will free spin by hand, then bank that the problem was the re-turn bring the fan on too much isntead.

Stock fan OEM settings,
Attachment 48335485

If when you spin the fan by hand, it feels like the bushing are grabbing/binding (instead of free spinning), then the fan motor bushings are toasted, so not only do you want to have the fan setting readjusted in the tune so the ECM is not bring the fan on so much, but you will need to replace the fan motor as well.

As for modding the upper connector to solve the melt down problem there with a better connector, all your doing is moving the problem farther down line, and will end up melting down the PWM and it connector next.



To sum it up, if your trying to hold the motor under 190* with the motor seeing a load, the only way your going to pull that off is with a better raditor and fan unit instead. The stock raditor and fan is designed to only hold the motor around 210* and over driving the fan to hold the motor at a lower temp just ends up with the fan/PWM/connectors burning up instead.