Ok I know there have been a few threads around about heater cores going, but I'm pretty sure mine isn't the heater core because I am not losing any coolant and I have pulled back the carpet in the passenger footwell and it's all good.

Whenever I have done a decent highway drive (I do gold coast to brisbane and vice versa a couple of times a week) or when I put my foot down, I get this nasty coolant smell that fills the car and I'm stumped as to why. Sometimes it happens and other times it doesn't but it happened for the first time last week and I started ****ting myself because the smell was really bad and my temp started to rise but only to about 10 oclock, and after I pulled into the shops and started driving again 20 minutes later it didn't creep up at all.

Everytime it happens I pull over and top up the coolant but it always seems to be full, and like I said I've checked the footwell carpet on the passenger side and there are no signs of leaks so I'm pretty much stumped.

Any ideas?

Any evidence of coolant leaks under the bonnet? Check all hoses and esp little hidden buggers near inlet manifold and heater hoses etc. Check thermostat housing gasket, and maybe check lower/underneath motor in case water pump seal going? (water pump in valley at drivers end of engine - behind timing belt covers).

When you say "top it up" - are you able to add ANY coolant, or always find it full? Are we talking radiator cap or overflow/expansion bottle you are checking?

Do you think the smell originates inside the car, or being sucked-in via air-con? Next time you get smell, turn air-con off or to re-circ setting - see if that varies the intensity of smell - at least you can guestimate if potential leak is inside or outside the cabin.

If temp guage is rising, I'd be searching recent (or any) threads about overheating and following some of the tips and checks in those threads....... Coolant does a good job and if you can smell it, it must be a sign of something amiss. Best trace it down and fix now to minimise risk of damage.