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- Jul 10, 2026
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My daughter’s 2009 Outback 2.5i non-turbo overheated twice out of the blue over a 1 week period.. The first time the car was parked as soon as the overheat was detected. It was towed to a reputable garage where they could find no issues with it. The second time the radiator blew after only about 6 or 8 blocks of driving and while she was getting it parked. The same shop wanted $1400 for a new radiator, hoses, thermostat, and coolant before it could do any more diagnosis. She declined as she just put $3K into unrelated work a few weeks prior. They had tested for bad head gaskets the first time one week before and they tested good then.
I installed a new Denso radiator and a MotoRad SuperStat. The car runs excellent but since I wasn’t sure about the cause of the issue I did not want to waste coolant and refilled it with distilled water. I went through the burp process and continued to let it run for 45 minutes without the gauge going above normal temp. The primary fan did come on once then off once in the 45 minutes. I had used a spill proof funnel and reached the point where the liquid stopped falling in the funnel, but I never stopped seeing bubbles. Thinking it was head gaskets I let it cool for about an hour before starting it again. After cooling, the level in the funnel had dropped about 1 inch, and when it was started there were no bubbles for several minutes but they did start after warming up.
My research showed that the normal operating temp for the coolant should be well below water’s boiling point. Water boils quicker than coolant but I believe it is better at transferring heat. Since it did not bubble at startup but waited until it was at operating temp can I assume the distilled water is boiling at the cooling port surface without the system coming up to temp? Or could the head gaskets be leaking once the engine warms up? I can put my nose right into the funnel but I don't smell any discernible combustion smell. I’m trying to figure out the problem without spending a lot more money. Any advice would be appreciated.
She spent $4K on head gaskets, timing belt, water pump, thermostat, tuneup, and fluids right after buying it 60,000 miles ago. $1K on tires this past year, $3K just weeks ago, and now this. It now has 170,000 on it. She is about ready to walk away from it.
I installed a new Denso radiator and a MotoRad SuperStat. The car runs excellent but since I wasn’t sure about the cause of the issue I did not want to waste coolant and refilled it with distilled water. I went through the burp process and continued to let it run for 45 minutes without the gauge going above normal temp. The primary fan did come on once then off once in the 45 minutes. I had used a spill proof funnel and reached the point where the liquid stopped falling in the funnel, but I never stopped seeing bubbles. Thinking it was head gaskets I let it cool for about an hour before starting it again. After cooling, the level in the funnel had dropped about 1 inch, and when it was started there were no bubbles for several minutes but they did start after warming up.
My research showed that the normal operating temp for the coolant should be well below water’s boiling point. Water boils quicker than coolant but I believe it is better at transferring heat. Since it did not bubble at startup but waited until it was at operating temp can I assume the distilled water is boiling at the cooling port surface without the system coming up to temp? Or could the head gaskets be leaking once the engine warms up? I can put my nose right into the funnel but I don't smell any discernible combustion smell. I’m trying to figure out the problem without spending a lot more money. Any advice would be appreciated.
She spent $4K on head gaskets, timing belt, water pump, thermostat, tuneup, and fluids right after buying it 60,000 miles ago. $1K on tires this past year, $3K just weeks ago, and now this. It now has 170,000 on it. She is about ready to walk away from it.