If head gasket was gone would temp gauge rise
 

Been reading so much into my smoke problem and im ****ting it incase its the head gasket, temp gauge never moves so would it if it was the head gasket?

depends where its gone

Get a sniff test done. Should confirm if exhaust gasses are present in the coolant

and if it is i take its very expensive fix

rebuilding mine at the moment. coolant coming out by battery on boost. car never over heated but defo a problem that needed to be fixed before it got worse.

mine smokes out of exhaust and some comes out bonnet scoop but doesnt happen all the time and when it foes its always at idle and when cars been run for quite a while

Overheating can be a symptom,might even be possible to see bubbling in the expansion tank. Easiest and best way is to get a sniff test done

My 95 WRX hg failure manifested itself as a rapid temp rise (almost into red) after about 10 mins but would then disappear. (Note, I was only travelling 15 mile journeys at the time).

I originally put it down to loss of coolant (always had to top it up when I got to work). Then realised that the loss of coolant was due to pressurisation caused by breakdown of HG allowing combustion gases into coolant.
Bubbling up in expansion tank on idle once warm.

But as has been said, the sniff test seems to be the best test.

White smoke = water issue

Blue smoke = oil issue

Black smoke = fuel issue

A engine can overheat and the temp guage read normal.

Air lock or lack of coolant flow or blockage can prevent circulating coolant passing over the sensor, giving a false reading.

Secondly the guage has a massive hysterisis in the "normal" range. "Normal" is actually between 80 degrees and over 100degrees. Usually it will stay in the mid way position right up until around 102degrees, then suddenly and quickly shoot into the red. This is the case with most modern cars; There is no mid-way reading on teh guage between normal and overheating, even if it looks like there is.

The only way to accurately confirm the engine coolant temp is with a laser thermometer on the water jacket, thermostat housing or heater hoses (heater on full heat, fan on minimum, A/C=off). EOBD diagnostic live data will give a direct reading of what the temp sender is "seeing" (assuming coolant is circulating).


Anyhoo, as mentioned many times; sniff test on the header tank will detect head gasket issues very easily.

been diagnosed as turbo is at fault

Nice easy warranty claim then :-)

So was it excessive black smoke then?

blue smoke.

black smoke is over fueling.