Heater and temp issues

[chilledawg]

Hi Guys, first post here!

Before I begin I have done a lot of searching on this and haven't been able to find anything specific that looks like the same issue my car is having, so..
I was just after a bit of advice on an issue I've been having with my 05 GT at the moment, I recently went on a long drive and when I arrived I noticed the temperature gauge was reading very high, I let the car cool and checked the coolant in the radiator to find it was empty, so I filled it up and drove it again only to find the gauge would read high again after a little while, I tried to do the old trick of heater on full and windows down however the heater did not blow any hot air out, but when I had to accelerate the heater would turn on and the temperature would drop slightly, then at idle the temp would raise again. I've now checked the coolant again after a few days and the radiator is still full, there's even some coolant in the reservoir. I can't see any leaks and all the radiator hoses appear fine, the thermal fans do turn on properly at idle and air is being blown around but still sometimes (most of the time really) the temp gauge reads high.

It just seems odd that this issue only seems to happen some of the time though, yesterday for example I drove to and from work with the temp gauge reading correctly the whole way. So does anyone know what might be causing this? a possible broken water pump or a blockage in the cooling system? But both of those issues would make me think this should happen every time I drive the car

Any ideas, questions or suggestions would be greatly appreciated guys

regards

[Robbks]

your heater core is blocked
Subaru's run ALL the coolant through the heater core
and when it blocks up you cook the engine and root the head gaskets

whip off the hoses through the firewall to the heater. and plug up the engine ends
get a garden hose and blast out that heater-core from both directions numerous times
marvel at the amount of brown sludge coming out
re[peat until you can get no more brown crap out
then slowly re-fill and over-fill the heater-core to make sure you get any air out
then re-fit the drivers side hose to the engine, keep filling the core to make sure you get any air out
then re-fit the other hose

run the car up to operating temp and put some revs on it (2500) and listen for any water-fall noises from the heater-box
if the noises don't clear the you'll need to follow the procedure i've posted a heap of times before for bleeding the air from the cooling system
otherwise, drive and enjoy.

if ti still overheats, you may have other issues
dodgy thermostat
blocked radiator
failed water-pump
or blown head-gaskets

[chilledawg]

Thanks for the reply Rob I'll see if I get time to do that this afternoon, any tricks on getting to the heater hoses? last time I had to get under the car the plastic tray was a real pain to get off

[Robbks]

heater hoses are at the top passenger side of the firewall
just pop the bonnet