Over heating issue driving me nuts
 

I have had an issue with my car for a few weeks which pointed to the thermostat. I was losing coolant also.
The temp guage was bouncing up n down between norman and red. The fan was coming on at to speed and then staying on for a good 5 to 10 mins after engine turn off
So i swapped out the old stat and housing for a genuine mgr one. Topped up the coolant. That was tuesday. Ran it for about 15 miles. Topped it up wed and thursday morning. Car ran with no issues.
Checked this morning and coolant is at correct level in the header tank.
Also installed new engine temp sensor.
Get 2 miles down road if that. Fan kicks in. I listened for it to cut out as per usual. It doesn't. The temp gauge then rises a fraction. Then bounces between normal and 3/4 mark.
What else can it be?
coolant if fine. New stat. No leaks or air locks as fan gets red hot on economy.
Fan is now coming on as soon as engine turns on and takes ages to go off.
Could it be the guage its seld sending mixed messages?



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A few years ago i had similar with coolant loss and fan staying on when parking up -this is what alerted me - turned out to be a failing IM gasket - however did not get any temp gauge issues. If i am losing coolant and the reason is not obvious i get her on ramp at a local garage and do a coolant pressure test - in the case of the failing IMG it took nearly an hour on the ramp before it started leaking visibly - when the engine was good and hot.

i am not losing coolant now

Thats what happened to me - i only lost coolant when the engine had been running for a while - on short journey's no coolant loss - only when the heat of an engine under load caused the IMG to leak - hence it took an hour of running on a ramp before the leak was evident.

img is ok as it was only replaced in December

Don't assume, check!
Which model do you have?

Hi, what is the I.M.G. please?

Inlet Manifold Gasket

Engine Temp sensor faulty or more likely wiring thereto, the engine thinks it hot when it isn't. Try a different sensor as they can be faulty when new.

You also need to run the on board temp display in the IPK to show the actual temperature the sensor is recording, the temp gauge is not accurate staying at the nine oclock position from 75 to 115 deg.