Driving to work this morning and noticed the temp needle was very high then it would drop and go high again, suspected a sticky thermostat.
Got the car home and noticed there was no coolant in the overflow and the radiator needed over 1 litre to top up, so looked like coolant loss more than thermostat, topped it up and now is okay, so started looking for the leak.
No oil contamination, but noticed that the heater hoses and the bottom hose where it attaches to the water pump had green powdery residue (on the ends after the clamps) indicating very minor leakage past the clamps, and there was puddles of green fluid in the indentations of the geabox housing indicating quite a big leak under pressure.
Looks like the leak is coming from the water pump area.
Pump and hoses are under 2 years old.
Do you think replacing the water pump is the first step??
And....does anyone use a sealant when fitting hoses or just rely on the clamps to provide a seal??

how new is the radiator cap

try this

remove all the hoses and clean the green corrosion bits off

and clean inside the pipes where the corrosion is also

then fit the hoses back on with good clamps

look for coolant dripping out of where the waterpump 0 ring is---- going into the block

just a quick one, make sure your fan is turning on too. I've had problems before where i'm sitting at the lights and the fan hasn't cut in (be it a relay, switch, whatever), and the temp gague has risen right up..i haven't noticed until i go to take off at which point i pulled over to discover i had 1.5L missing from the radiator. Boiled over real easy, straight out the overflow.

I know you said it was leaking, just sharing experience ;)

CHANGE YOUR FAN RELAY!!!!!!!! exactly what happened to mine last year. avoid the trouble of rigging the head off to replace the gasket and change the relay stat!

CHANGE YOUR FAN RELAY!!!!!!!! exactly what happened to mine last year. avoid the trouble of rigging the head off to replace the gasket and change the relay stat!

if you were talking about me, yeah i got it fixed straight after it happened.
incidentally as a temp fix you can just leave the a/c running, they have a separate relay for the fun, and it still turns on.

Just to not start a new thread id ride this one..

My 3rd gen has been doing this too, while driving last saturday the temp needle rose to 3/4 then back down to a little bit over halfway.. Then sometimes randomly it would go up and back down again. Never back down to normal just a little bit over.

Today drove it and was fine. But might have been because i didnt drive for long enough (takes 10 mins to get to work).

Would this have anything to do with my heater core problem (cracked, leaking coolant)??? I've ordered the part and hopefully comes in soon so i can get that fixed. Btw radiator coolant is topped up, no loss there. does that mean that im not leaking coolant?

I read another thread about mechanics adding problems to cars.. Hoping the mitsu dealership didnt wack on a cracked heater core to get money out of me (they were asking for 1000 to fix), who knows these days.. I would have payed them too if it wasnt for me coming on here.

If it was heater core it's about $600 - $700 to fix. Dealerships are too pricey go to mechanic.

Yeah madmagna has contacted me about that, was just wondering really what the go with the temp gauge was, like if its due to my heater core leaking coolant or if its another factor?

You may have had an airlock in the system if the coolant level got low, this then bled itself when the thermostat eventually opened.

When you change coolant, you generally bleed the cooling system to stop this.

In Kempowens case, from memory most hoses were new and there is no "green stuff". Could be radiator blocked but again I highly doubt it.

One issue is that when the head is cold it may test ok but when warm it seeps thus coolant loss