Bought this car in January with 141k miles on it, two previous owners. In February, had a mechanic friend of the family inspect the car and he sealed the coolant with Prestone (saying what it was before) and added a half pipe of alumaseal because he saw what he thought might be coolant leaking from the head gasket ( very small, not even a drop). In May, I noticed the coolant level was a little low, but I didn’t have the Subaru coolant on hand, so I didn’t do anything about it for a month or so. In June, there was a near overheating event where the needle was almost in the red, I think around 103-104°C. Checked the coolant level once it was cool enough and it was low so added some blue Zerex coolant to seal the radiator. I had also bought a new radiator cap a few weeks ago. No more overheating, but the radiator still sags when I check it cold. However, the overflow tank is full and when I remove the radiator cap I hear a sucking sound. If I understand correctly, coolant expands to overflow when hot and is supposed to reabsorb when cold. So my guess is there’s a leak somewhere that’s letting air into the system instead of coolant from the overflow tank, or the radiator cap isn’t working properly (I checked by squeezing the spring and it seems fine). It might have something to do with this debris in the driver’s footwell, which I don’t think can come from road water. Could it be a heater core leak? It doesn’t feel damp in there after driving and it doesn’t smell like coolant, and the heater works when I turn on the hot air, so I don’t think it’s plugged in. There is also a screeching sound now behind the dashboard, and has been for several months. Would it make sense that the heater core could allow air into the system when it cools down, explaining the radiator not recharging and the pitch noise? Below are some pictures I took to illustrate the situation.
Foot Rests:
Full Coolant Overflow Tank:
Radiator cap seal interfaces:
Radiator cap:
I can see the top of the fins, it happened after only a few hundred miles of driving (no I don’t have white exhaust).
I checked the return hose that goes from the tank to the radiator and I can blow air through it so it’s not blocked. Not even puddles on the ground. Am I missing something? Is it alumaseal? My ungodly mix of coolants?
Thank you in advance!
