Hi any comments appreciated,1996 Legacy 2.5 4cam auto estate temp gauge going up to hot then down to normal,heater coming and going expansion tank level was fine but took couple of litres in rad drove 200 miles home heater fine and temp gauge didnt move stopped for fuel 5 miles from home then ran hot back to home,then when cold topped up again.
No water in oil loss of power or obvious steam from exhaust.
Radiator cap not sealing ??
Thermostat not working ???
Am I on the right track and is the thermostat easy to replace or remove
Regards Derek

 

Hi, sounds like it could be getting airlocked, might have a leak hence having to top it up. Sounds like when its topped up it runs okay, when it stopped the pump may have got airlocked. I had similar issue with a previous impreza, turned out to be a leaky rad letting coolant out & air in. Also had similar issue with honda civic recently, which turned out to be airlocked after changing the rad. I could tell as when it was on the drive, ran it up to temp and when revving it a little i could hear gurgling in the heater core. Cured it by topping up the rad direct via the top hose and a bit of squeezing of hoses etc

As for the cause of the leak, my first guess would be the rad, but its just a guess

 

There are a couple of possibilities that you need to investigate here. Thermostat, Airblock are 2 of them - absolute worst case scenario it could be a head gasket problem.

Check if the cooling fans are cutting in and out when they should do and also check to see if the heaters inside the car work OK. Quickest and easiest way to rule out a head gasket would be a sniff test which most garages should be able to do for you fairly quickly and cheaply.

 

Fans are cutting in fine cant see any visable rad leaks heater nice and toastie,the temp was rising whilst going up hill so obviously under load and maybe not enough water for the pump to work,thinking the airlock is the prob water pump fine I think will expell water when rad cap off,is the thermostat easy to get to and remove havent looked that far yet Thanks Derek

 

Head gasket's gone, happens all the time on those.