hot idle

[sawman]

I noticed today that when stuck in traffic the temp gauge going up significantly (it normally barely moves once up to temp) on my H6 outback. When on the move things cool down quickly, and the fans are cutting in. I am waiting for it to cool off a bit before investigating the coolant reservoir I am not seeing any obvious coolant leaks.

Any thoughts? head gasket? knackered rad?

I have been praising its reliability all week......

[texaxile]

Airlock?.

Going on Impreza systems, they have to hold a vacuum in order for the coolant which goes into the expansion tank to return after the car is turned off. I had a small leak on mine which meant the coolant went into the tank but didn't return (previous owner thought it was HG). When I sorted the pinhole leak the system needed to be "burped" by squeezing the air out of the hoses as the engine was running with the upper coolant reservoir cap off.

I understand that Subaru's are known for this occasionally, but of course on a formerly functioning system the air has to be introduced by way of a leak somewhere.

The leak was in the upper reservoir but at the back, so the coolant was dripping onto the manifold and evaporating causing a coolant smell in the cabin.

If it's an HG check the expansion tank for small "champagne" bubbles (occasional large bubbles are perfectly normal) during idle and load, plus of course coolant levels, mayonnaise like mixture on dipstick and filler cap.

Could also be a bksed thermostat, stuck half way open, not unknown on any vehicle.

[sawman]

cheers, I'll investigate more tomorrow, a quick look shows a low level of coolant in the reservoir, so maybe there is a leak somewhere, there aren't any tell tale drips on the drive. no sign of mixed fluids.

in addition to the rapid rise of the temp needle when getting stuck in traffic, the cabin heater seemed pretty week today (usually it gets toasty pretty quickly - one of the benefits of slurping all that petrol!)

[texaxile]

Without wanting to confirm or deny, sounds suspiciously like a blockage or airlock. My heater was the same, throwing out lukewarm air when set at 30. There's a good guide on scoobynet and a good few on youtube for burping the system, and afterwards following a top up mine was absolutely fine.

If it is a thermostat then they're about £15-£25 quid for a genuine one on Ebay (For Impreza - I think they're a shared component) but check the coolant you need, because I think it has to be genuine subaru £22+VAT per gallon from dealers). I have looked for an alternative but there's no definitive options as far as I could see. No idea about replacing them though.

Hope it's an easy fix!.

[leefee]

Is it the last of the old shape up to 2003 ? They seem to have a habit of HG at around 100k, the newer ones for whatever reason ime don't..
I have had 3 of the older ones over the years that have had HG issues at around 100k. symptoms were all, the overflow bottle filling up and the car overheating at idle... I was convinced each time it was just a blockage, or air lock.... it never was....

[sawman]

I havent managed to explore any further as yet, but on a 20 minute run in slow traffic yesterday, no ptobs, today after 30 mins dual carriage way and 10 minutes in crawling traffic the needle made its way to the bottom of the red zone.

Will have a good scout around tomorrow

its a 2007 92k on the clock, I really hope its not a HG issue

[sawman]

Diagnosis: small radiator leak - could have been worse, could have been better....

[74merc]

Nissens should have an aftermarket rad for not much money. I bought one for my Forester from JD motorsport via ebay.

[sawman]

all sorted now - should be good for another 100k miles,