2006 legacy 3.0 spec b overheating

[Nate_zr132]

Hi guys, so for those of you who don't know I picked up a legacy estate 3.0 spec b at the end of august. On my back from the dealer into full time ownership and about a mile from home noticed the temperature had started to rise very close to the red, this happened while on an uphill stretch and it was the first time I'd noticed anything untoward on the journey. Have driven it a few times since on shortish journey's and the same thing happens on uphill stretches.

Weird thing is it settles back to halfway or just below when the car is going downhill and fluctuates a little between hot and cold when on the level. Have had a look on various forums already without coming across this kind of issue being written about.

(Copied the below over from a thread I have uploaded in a fellow legacy forum. Not chronologically accurate) 

So a small update to my rather confusing issue. Drove my car around locally today and found she behaved mostly perfectly, again the temperature rose when travelling uphill under load. Had a couple of occasions where I was sat stationary in queue's of traffic that happened to be on hills and had the car in neutral - no issues. Placed the car in D and applied the throttle the temperature rose.

Other than these small uphills had no temperature issues even when driving the car at a steady 50-60mph for one stretch. Pulled off some quick overtaking manoeuvres to overtake some slower cars on my ring road (approx 20 up to 40/45mph) and the temperature rose again before settling back down as soon as I went back to cruising.

 

I took the car out again tonight (06/09) and she behaved impeccably on the way out to food. Held a steady 50 on cruise control with no rises in temperature, no fans on when stopped. On the way back from picking up food she held a steady 50 on cruise control again with no temp rises and only started to rise in temp when going uphill.

 

All suggestions welcome, if some discussion gets going then even better for me :)
 

[Bren]

Mine did this too, though it's a lot older and I got mine dirt cheap as the seller was honest about it. Also had a slightly lumpy idle in N but not D. I looked through the service history and noticed it had missed the heads re-torque and camchain tensioner replacements. Also noticed that the overflow tank was filling up but not siphoning back to the radiator so my guess was a head gasket issue pressurising the system.

Am still waiting for the mechanic I use to have time to fit it in. In the meantime I flushed the cooling system and for 2 weeks ran it with just water and the Subaru recommended coolant additive which turns out to be re-packaged Holts Radweld Plus. I started with half a bottle and added another bottle and a half incrementally as I couldn't see the point in just pushing it all out the overflow tank. No climbing temperature or lumpy idle  issues in a thousand miles since including long uphills fully laden with the family on board and a boot full except once in a while it will need a small coolant top up (maybe half a cup) when I also add a small shot of the additive .

I normally use a bike so don't rely totally on the car except when it's icy or snowing.  If I was in your shoes I'd pop back to the dealer and get them to take it for a run with you to get the problem acknowledged and ask them to get the cylinders pressure tested to eliminate head gasket issues while you're still under the protection of the sales of goods act unless they gave you an excellent warranty.

Good luck with getting it sorted.

Bren