2005 SV6 issue

[Mattt]

Hey guys and gals.

I've just recently noticed a very concerning issue with my SV6. The temp gauge is starting to rise very high and the heater is also playing up.
I suspect they are somehow related as they both started happening at the same time. The heat issue isn't an issue when I'm sitting at 110 on the freeway generally, although 140 was the speed that managed to bring the temp down to a 1/4. Anything below this speed and the temp will rise to anywhere from 1/2 to 3/4. I've stopped before it got any higher but I know it will rise again.
The heater issue is basically that it often wont work on start up, it'll blow cool air, even after the car had heated up. Usually a bit of a rev will smark it into action and then it'll be ok.
Just a few minutes ago i was coming from 100 to 60kmh and the heater just switched back to cool then back to heat which i found very strange.

Now I'll be honest, I have very little clue when it comes to cars, so from what i have described can anyone give me any idea as to what is the issue I'm facing?

Thanks in advance

[Duz108]

Could be thermostat for both problems, vzs also have a tendency for the water pump to fail. Check that you actually have coolant still, as if the pumps dead it will be leaking

[Munz]

i thought that the heater won't work on start up cause the engine is still cold - unsure live in QLD never gets cold enuff for heater

[Mattt]

Thanks for the replies. There is plenty of coolant so hopefully that eliminates a broken pump. Water levels in the engine were quite low so i out roughly 2 litres in to fill it up. Will drive it out to a garage and see what they say.

Munz, you're right, its generally cold on start up however it usually heats up as the engine gets hot, mine stays cold even when the engine has had time to warm up.

Thanks for the help guys

EDIT: Had a look and noticed a lot of water missing from radiator. Topped her up and she is working fine. Now the fun task of locating the leak

[Mattt]

Ok so this morning the car had lost a litre of water from the engine. Now looked last night and this morning and there was no sign of a leak on the concrete below. Any one have any idea where the water could be leaking? Very concerned as to where 3+ litres of water has vanished to

[impulsive]

look for signs of the color of your coolant on your engine bay, or perhaps even white crusty marks

[heyitsEnricoPallazzo]

Is the coolant overflow full?

Are you bleeding the cooling system properly?

Are you using proper coolant?

[Luke52]

Take off the drivers side engine cover, and look for a leak around your heater tap.

Mine was leaking for months before I noticed it, but there was never any coolant on the ground under the car, it was just dripping onto the exhaust manifold and evaporating, leaving the whire/red crusty, gooey marks that Impulsive mentioned.

Also, check/change the radiator cap. Common problem for us VZ owners.

I had this exact problem a few months back. Car overheating, coolant disappearing, heater not working properly...all fixed by changing the rad cap.

[crazy2009]

Had same issue only 3 months ago waterpump and seals replaced all good now not cheap fix was apprx $600