Evo Temp Gauge Fluctuating?

[Deza3000]

Okay so here's the scenario:

cold starts: (first symptom)

- When warming up the car i notice the temp gauge going up slowly, however when i turn my steering wheel, it dips back down to cold (only a minor movement, so i ignored it)

Under heavy driving: (second symptom)

- While cruising on 40ks per hour, i downshifted @ WOT to join the road, and noticed the temp gauge drop from its normal position (roughly around the middle) all the way to cold, then slowly started climbing back up again....

Starting to worry me now, i dont know if its a bad thermostat, lose connection, bad water pump or bad radiator...however if it was the radiator then i would of fried the motor a long time ago. I dont want to fry the gaskets if it is the water pump. Not too sure, anyone have any insight?

The fluctuation usually happens when i push the car. Under normal driving it seems fine....for now, (although ive just noticed it today, yet to see if it acutally fluctuates while crusing)

Note: just changed my radiator to a brand new one, old one cracked.

[GTR-N1]

Usually the temp needle on the EVO sits just below halfway.

Is your reservoir full, but the rad is down on coolant?

If so, there's a leak, maybe a small one from a hose or at the top of the intake manifold.

Is there a puddle underneath where you park it?

Water pump perhaps if there is.

Are the rad hoses firm whilst idling?

After the rad was changed, was the system bled of any air?

This is what I suspect most of all, because further bleeding may need to be done on the 2nd day.

[Deza3000]

Usually the temp needle on the EVO sits just below halfway.

Is your reservoir full, but the rad is down on coolant?

If so, there's a leak, maybe a small one from a hose or at the top of the intake manifold.

Is there a puddle underneath where you park it?

Water pump perhaps if there is.

Are the rad hoses firm whilst idling?

After the rad was changed, was the system bled of any air?

This is what I suspect most of all, because further bleeding may need to be done on the 2nd day.

The rad was still hot so i couldnt check it today, a bit dark now so ill have a look tomorrow afternoon. But so far there is no leak and no puddles. Also no sign on white stains in the engine bay so i guess i can cancel out high pressure leak. The Rad was changed 1 month ago..roughly. It was also flushed, it was done by Revzone in ringwood.

Happens every time i throttle, doesnt go above the normal temp, only below, so drops all the way to "L" then goes back up just under the middle, as you said. Im starting to think either thermostat or air in the system as you said.

Do i just turn on the car and open the rad cap and let it warm up to bleed the air?